26 multi-kiloton nuclear sized explosions detected in Earth’s atmosphere since 2001

The biggest threat to humanity, far bigger than global warming/climate change, is about to get bigger, much bigger

chelyabinsk-asteroid-fireball

The chelyabinsk asteroid fireball, a “near-Earth object” (NEO), an asteroid (likely made of rock) between 15 and 20 meters across (about the length of a school bus), which just happened to arrive in the same place as planet Earth that morning. The mass of the object was about 10 thousand tons. It struck the atmosphere moving at about 40,000 MPH (more than double the speed of the Space Shuttle).

A press release from some former NASA astronauts on the current asteroid impact threat to earth, based on data on in-atmosphere detonations since 2001, gleaned from a nuclear weapon detonation detection system has yielded some startling numbers.

The threat is 3 to 10 times higher than previously predicted. The data will be presented at the Seattle Flight Museum, Tuesday April 22, at 6:00pm PDT.

Just last night, another fireball was seen over Russia, caught on a dashcamera. See video.

Now it becomes apparent why this press release is important.

This Earth Day, Tuesday, April 22, three former NASA astronauts will present new evidence that our planet has experienced many more large-scale asteroid impacts over the past decade than previously thought… three to ten times more, in fact. A new visualization of data from a nuclear weapons warning network, to be unveiled by B612 Foundation CEO Ed Lu during the evening event at Seattle’s Museum of Flight, shows that “the only thing preventing a catastrophe from a ‘city-killer’ sized asteroid is blind luck.”

Since 2001, 26 atomic-bomb-scale explosions have occurred in remote locations around the world, far from populated areas, made evident by a nuclear weapons test warning network. In a recent press release B612 Foundation CEO Ed Lu states:

“This network has detected 26 multi-kiloton explosions since 2001, all of which are due to asteroid impacts. It shows that asteroid impacts are NOT rare—but actually 3-10 times more common than we previously thought. The fact that none of these asteroid impacts shown in the video was detected in advance is proof that the only thing preventing a catastrophe from a ‘city-killer’ sized asteroid is blind luck. The goal of the B612 Sentinel mission is to find and track asteroids decades before they hit Earth, allowing us to easily deflect them.”

In partnership with Ball Aerospace, the B612 Foundation will build, launch, and operate an infrared space telescope to find and track the hundreds of thousands of threatening asteroids that cannot be tracked with current telescopes. See the mission pager here

Read the press release at:http://b612foundation.org/news/b612-press-conference-on-protecting-earth-from-asteroid-impacts/

h/t to reader “Mac the Knife”.

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148 thoughts on “26 multi-kiloton nuclear sized explosions detected in Earth’s atmosphere since 2001

  1. Eeeeeeek!
    No seriously though…these little fellas have been doing this since for ever. We mustn’t confuse the ubiquity of camera phones etc etc with increasing frequency, we’ll be seeing lots more of this type of thing.
    As for tracking big ones then doing something about them before they hit…I think this is what you might call a ‘Hollywood’ type solution to the problem. i.e. fantasy.
    When a commercial jet the size of several houses can disappear radar controlled, satellite monitored air-space. I don’t hold out much hope for our technology being able to track smaller faster objects approaching our spherical planet from the corners of the cosmos!
    Good to know that we’re thickening up the atmosphere with added CO2 though, most of those bad boys will burst and burn up long before they ever hit the ground!
    And what about the weather in Murmansk…?

  2. How much Asteroid deflection capability would the annual global warming mitigation budget buy?

    Time to stop that fantasy, and spend money where it is really needed.

  3. I’m sorry Charles Nelson, but you don’t know what you are talking about. Comparing an aircraft that can change course to evade detection and an unguided rock that must follow the rules of orbital mechanics is just silly. Plus the rocks we are really concerned about are a bit bigger than even a 777. We can find and track these objects with the technology that we have now. And if we work at it, we could have the resources in place to deflect one within a few decades. And since a large meteor is a REAL civilization ending event, we must do it.

  4. “And since a large meteor is a REAL civilization ending event, we must do it.”

    1. It won’t be such an event in a hundred years, since we’ll have plenty of people living off Earth by then (or have wiped ourselves out).
    2. The odds of a city being destroyed by a meteor in the next hundred years are minute. The odds of civilization ending in the next hundred years due to a meteor impact are barely worth thinking about.

    As with ‘Global Warming’, the cost of preventing such an impact would be far more than the likely cost of doing nothing. Few possible impactors could have more than local impact, and so little of the Earth’s surface is built on that most of the others would hit relatively uninhabited areas.

  5. “actually 3-10 times more common than we previously thought. The fact that none of these asteroid impacts shown in the video was detected in advance is proof that the only thing preventing a catastrophe from a ‘city-killer’ sized asteroid is blind luck”

    Given that the last extinction level event from one was 65 million years ago, I’m not going to lose much sleep over the infinitesimally small probability of one occurring within my comparative eye-blink of a lifespan.

    And really – does anyone think we’d stand a chance of deflecting several hundred thousand tons of metal hurtling towards us, as this stage of our technological advancement? “Armageddon” it ain’t.

  6. The two largest ground strikes in the past ~100 years have been in the region of Russia. And now two events in less than 12 months in the same region. Strange.

  7. > The biggest threat to humanity, far bigger than global warming/climate change, is about to get bigger, much bigger

    No, no – the threat remains the same (per capita), It’s merely the perception of the risk that has narrowed and gone up.

    It does make me wish that we had spent a little more time getting some of us off this basket. A planet is a great place to evolve, but it’s a lousy place to preserve a species.

  8. http://www.mapsofworld.com/russia/distance-calculator/chelyabinsk-to-murmansk.html

    hunter says:
    April 19, 2014 at 4:10 pm

    > The two largest ground strikes in the past ~100 years have been in the region of Russia. And now two events in less than 12 months in the same region. Strange.

    Umm, Russia is big. http://www.mapsofworld.com/russia/distance-calculator/chelyabinsk-to-murmansk.html says the recent events are 2000 km apart. Murmansk is near Finland, Tunguska is at longitude 90°E.

  9. Calculate effect of asteroid impact in your neighborhood:

    http://www.purdue.edu/impactearth

    Frequency data prior to the study referred to in this post:

    http://rsta.royalsocietypublishing.org/content/363/1837/2793.full

    For objects greater than 1 km, forming craters greater than 20 km, we use estimates of flux based on the terrestrial crater population by Grieve & Shoemaker (1994) and Hughes (1999, 2000), and from the NEO population by Rabinowitz et al. (2000), Stuart (2001), Morbidelli et al. (2002) and Harris (2003). To fit these data, rather than simply taking the best-fit power law, we can also use the SFD of lunar craters as a guide. Neukum et al. (2001), Werner et al. (2002) and Ivanov et al. (2003) have demonstrated that the overall shape of the NEO and Main Belt asteroid mass distribution (Rabinowitz et al. 2000; Stuart 2001; Morbidelli et al. 2002) is similar to the cumulative SFD of lunar mare craters (the Neukum or Hartmann Production Functions—NPF or HPF). In addition, NPF and HPF curves are used in crater counting studies to date surfaces of all ages throughout the inner Solar System. Given a maximum factor of 3 error in any particular region of the HPF/NPF curve (Ivanov et al. 2003), we use this curve to fit the large NEO and terrestrial crater dataset. Although other fits to the upper atmosphere data are possible (Bland & Artemieva in press), we note that the resulting curve is a close fit (within a factor of 3) to virtually all the available data. This analysis suggests that we can expect the impact on Earth of a body sufficient to form a 10 km crater once every 200 kyr (craters on land will be formed by these objects every 690 kyr). Bodies big enough to make a 20 km crater will hit every 600 kyr; 50 km events will occur every 3 Myr; 100 km events every 13 Myr; 150 km events every 38 Myr; and 200 km events every 80 Myr.

  10. Darby, compared to Win8, Vista was great.

    If you have decades of warning, it doesn’t take much to deflect. The equivalent to a hand grenade exploded in the vicinity, or an Estes model rock engine worth of thrust. However, just because we now realize there are more doesn’t in any way make the threat any greater.

  11. That rate is approximately 2 per year.
    If the U.S. occupies about 2% of the worlds surface area and the meteor re-entry locations are totally random then the probability is not all that high. Something in the order of once every 50 years or so a kiloton yield impact should occur over U.S. territory. (yes I know the U.S. is not the world just working out a representative example.) In my 60+ year life time I can recall several nationally publicized fire ball events over the U.S. that had blast pressures significant enough to rattle windows rouse people from deep sleep. How many of those were actually Chelyabinsk class events which simply occurred in remote enough areas they did no damage to human structures?

    The hidden message here is that previous estimations of the likelihood of larger bodies striking the earth (Tunguska class events) might also be an order of magnitude lower than reality.

    The most recent “known” crater forming impact of significant size is the Barringer crater impact which is estimated to have occurred about 20,000 to 50,000 years ago. A couple other much smaller cratering events have been documented in the middle east deserts and Peru if I recall correctly. Events which only left craters a couple meters wide. Who is to say if a Barringer class event impact at sea would even be detected and recorded in the recent historical record unless it occurred close enough to a populated area for the flash to be seen or the impact tidal wave to have been recorded as associated with a meteor impact.

    Even the smaller meter wide crater events could cause a very bad day locally if they struck critical facilities, like dams bridges or occupied sky scrapers.

    It is simply good emergency management to consider well known hazards which are inevitable. We plan for 100 year floods, and 50-100 year earth quakes, why not 100-1000 year meteor impacts?

    As above, a much more productive use of funds than expenditures to deal with a fantasy threat from a temperature rise that occurs every morning between 8:00 and 8:30 AM in most habitable areas of the globe.

  12. makes me wonder…..since all this crap is constantly falling on the earth

    Is it really making it bigger?
    Messing with the rotation, orbit?
    That and sediments, raising sea levels?
    …anything?

    How much space stuff is actually falling on us?

  13. …Since 2001, 26 atomic-bomb-scale explosions have occurred in remote locations around the world…

    NO! This can’t be the case!

    I was told that the science was settled on 4 atomic bombs a second. Why has it changed?

  14. A city killer might strike, but since Sodom and Gomorrah we haven’t seen one. As far as “End of the world as we know it” sized asteroids– I’m more likely to get a date tonight with this month’s Playmate of the Month than we are to get hit with one of those things. 65 million years, and Jupiter helping to clean up the place… don’t lose sleep over a “planet killer”.

  15. I believe the threat of falling spacecraft remains larger than that of meteors and asteroids. If not, at least falling aircraft could give the space rocks a run for their money, not to mention ICBMs.
    –AGF

  16. Very bad things are going to happen to a lot of people in the next 100 years. Gearing up to deflect an asteroid is ludicrous, both for the cost in resources and time away from more promising ventures……food and energy. It is expected we will watch the asteroid traffic patterns, but only in the way we look at weather. You get out of the way, if you can, and if you can’t then one of those very bad things is about to happen to you.

  17. Geological evidence show earth has been hit by large meteors (5 km diameter) every 10 to 20 million years. The last big hit was 35 million years ago. We are overdue to be hit again. NASA has mapped out the trajectories of < 1,000 big Near Earth Objects in the asteroid belt. There is still < 100 NEOs in the asteroid belt that can hit earth. However, NASA has not searched the Kuiper belt which has over 100,000 objects and the Oort cloud which has over a trillion objects.

  18. BTW these large meteors can cause tsunamis higher than the Empire State Building. We have never seen this kind of catastrophe since man evolved from apes.

  19. “…our planet has experienced many more large-scale asteroid impacts over the past decade than previously thought… three to ten times more, in fact.”

    Have any alarmists made the claim that climate change is causing more asteroid impacts? If not, it’s just a matter of time.

  20. Louis
    Have any alarmists made the claim that climate change is causing more asteroid impacts? If not, it’s just a matter of time.

    Absolutely – model projections predict that global warming shall cause the atmosphere to expand as it heats, increasing the risk of dragging meteors down onto our heads.

  21. CodeTech says:

    April 19, 2014 at 4:38 pm

    Darby, compared to Win8, Vista was great.
    ====================================

    Google “Classic Shell”, Makes W8 look like W7 or even XP. Much easier to live with W8 now.

  22. Dr. Strangelove says:
    April 19, 2014 at 5:11 pm
    “We are overdue to be hit again.”
    ======================================
    Not necessarily. No matter how any heads you toss, chances of next tossing tails remain 1/2. Asteroid collisions would first need to be shown to be of non-random frequency to make such a claim, and your 35mya collision goes against the usual 100my or so frequency claim. –AGF

  23. See Judith Curry yesterday, or the add on wrap she says she will post soon.
    Some things are so improbable they are not worth insuring against. The 2014 March Madness perfect bracket is a great example where Warren Buffet made money at ‘asteroid’ expense.
    Please do not take this bog in that direction.

  24. A very large impact on land would do us some serious damage. A very large impact in the middle of the Pacific ocean, would cause some serious ripples that would travel right around the world taking out every thing in it’s path. Goodbye most of us. Has happened before.

  25. There were three different 5 km wide asteroid impacts 35.5 million years ago. There is no evidence that there was any impacts on the climate from these impacts. The data has 1000 year resolution here and there is no change in the numbers. It was not a good day on planet Earth during those impact days, but these were not extinction events.

    It looks like Earth has only been hit by the really devastating 10 km asteroids about 2 or 3 times that we know of. Obviously more than that, but there are no impact craters for the 10 km extinction level events other than 2 of them. The really really bad 50 km wide comet impacts don’t seem to have ever happened that we know about. Large comets coming in at faster speed are the biggest issue, potentially eliminating all life on the planet, including bacteria living deep in the crust.

    The question becomes what do we do about the large asteroids that we find. If it is 3 kms wide, do we just take the impact. Easier than 50 smaller impacts causing wide-spread devastation. We have to make sure all the parts miss the Earth. If it is 10 km wide, we better try to stop it. Only people living in mines for 5 years would survive this size. But we don’t want to turn a 10 km impact into 10000 smaller impacts. We still don’t know what the best solution is.

  26. The Descent Promenade of the Gods to Battle (transliteration)

    Think (i.e. remember hearing Les Préludes). I’lll add that as a bit of fun ;-).
    Ha ha

  27. Their claim that the threat from asteriods is ‘3-10 times higher than previously predicted’ is a data hockeystick.

    Sounds like a sales pitch to me.

  28. @Ric Werme 4:31 pm:

    hunter says:
    April 19, 2014 at 4:10 pm

    > The two largest ground strikes in the past ~100 years have been in the region of Russia. And now two events in less than 12 months in the same region. Strange.

    Umm, Russia is big. http://www.mapsofworld.com/russia/distance-calculator/chelyabinsk-to-murmansk.html says the recent events are 2000 km apart. Murmansk is near Finland, Tunguska is at longitude 90°E.

    The first part of hunter’s statement is more or less correct, if he was meaning Tunguska and Chelyabinsk. Many people made the same observation 114 months ago. Hunter DOES say, “and now the two most recent…”, so I think I am reading him right as to Chelyabinsk and Murmansk being the ones being “in less than 12 months.” (Actually 14 months, though…)

    You including Tunguska by name when he had not mentioned it is a bit off kilter (me, too). Between his tw0 events in 12 months [sic], Chelyabkinsk and Murmansk are almost on the same latitude (averaged to the nearest degree, they ARE), but 2400 km apart.

    That part is a bit freaky.

    For comparison’s sake Murmansk-Chelyabinsk are about as close as NYC to Oklahoma City; while Americans think that is not “the same region” many people around the world consider them part of America which is only about 5% of the land area of the world, so it might depend on one’s perspective. Chelyabinsk-Tunguska is about the same as NYC-Amarillo, just a bit further. with the same points being made about the 5% American “region” and perspective…

  29. I am surprised at the lack of knowledge of the work stemming from that of Clube and Napier exhibeted by those who have already commented. If they are correct, right now we are in a quiet period. Things were much busier in ancient historical time with the events of that period coming down to us as apocryphal legend.

  30. Larry Ledwick says:
    April 19, 2014 at 4:38 pm

    Thanks for adding perspective. We do not need an asteroid tax.

  31. Your readers, usually a perceptive bunch, are missing the connection to AGW theory. Abrupt climate change that heralded the Younger Dryas cold period, as discovered more or less by Wally Broecker of Columbia, is used to stoke fear that a silent similar “tipping point” may be approaching as a result of CO2 contributions. There might be something to that — if the Younger Dryas had not been caused by an asteroid or comet. The Younger Dryas Impact Hypothesis, if proven, would undermine the effort to portray abrupt climate change as a closed system phenomena. As your tormentors at Real Climate acknowledge here:

    “Think about it. If it turned out that rapid climate change events are caused by comets, it would imply the climate system is far more stable than we thought, that abrupt climate change events are not part of the inherent variability of climate during glacial periods. That would perhaps allay fears that we could be pushing the system towards an abrupt climate change in the future. On the other hand, it would also suggest that cometary impacts are far far more common than we thought. Now that would be news. Perhaps further research by Kennett, Firestone and others will indeed show that to be the case. We’re not, however, holding our breath. – See more at: http://www.realclimate.org/index.php/archives/2009/01/the-younger-dryas-comet-impact-hypothesis-gem-of-an-idea-or-fools-gold/#sthash.5vngrqLQ.dpuf

    I would note that they are still holding their breath despite dozens of additional confirmations since the blog post was written.

    I am a co-author of several of the important papers supporting the YDB hypothesis and we need all the support we can get. Climate skeptics are one of many important constituencies that need to wake up to mankind’s truly greatest threat. Arguing about AGW is like fighting about the radio station while we sit on the train tracks. Asteroids are not so easily blamed on politics or people.

  32. I hate to say it but I doubt anybody’s going to bother doing diddly squat about this because preparing for this would be a strict outlay of money without the ability to make any money. That’s the only reason our world saviors pursue the CAGW meme: It’s very lucrative financially and since that threat is virtually nonexistent it only requires nonexistent remedies, and a nonexistent remedy, by its very definition, is a vanishingly cheap thing to produce but, yeah can you charge for it – hence the financially lucrative aspect.

    As an aside:
    2900-7300 kilograms per year hit Earth. However, this does not include the small dust particles. Scientists also estimate between 36 and 166 meteorites larger than 10 grams fall to Earth per million square kilometers per year. Over the whole surface area of Earth, that translates to 18,000 to 84,000 meteorites bigger than 10 grams per year. But most meteorites are too small to actually fall all the way to the surface. Estimates for the total mass of material that falls on Earth each year range from 37,000-78,000 tons. Most of this mass would come from dust-sized particles. (This study was led by P. A. Bland and was published in Monthly Notices of the Royal Astronomical Society.)

  33. Just what we need … another science of disaster out to save us all.

    Let’s see if I’ve got the math down … 26 explosions since 2001 or 13 years, which comes to an explosion occurring once every six months on average.

    There go those darn skeptic alarm bells, such as … what happened every six months for millennia … we had blind luck all that time?

  34. . . . . . . .
    ~ The upper atmosphere incinerates the vast majority of small and medium sized space rocks that enter it.
    ~ Any remaining pieces would likely fall onto the oceans (71% of the Earth’s surface), or onto the deserts and arctic areas.
    ~ Whole sky surveys assure us that there aren’t any *large asteroids* in our neighborhood that we need to be concerned about.
    ~ Even if there is a large asteroid sometime in the distant future, mankind now has the ability to nudge it into a safer trajectory.
    ~ There is zero telescopic evidence from the Earth, and satellites, of any other large objects in the inner solar system.
    ~ There are many thousands of mostly amateur astronomers around the World who would advise us of any other objects.
    . . . . . . .

  35. “No one should be overly concerned about an Earth impact of an asteroid or comet. The threat to any one person from auto accidents, disease, other natural disasters and a variety of other problems is much higher than the threat from NEOs [Near Earth Objects]. Over long periods of time, however, the chances of the Earth being impacted are not negligible so that some form of NEO insurance is warranted. At the moment, our best insurance rests with the NEO scientists and their efforts to first find these objects and then track their motions into the future. We need to first find them, then keep an eye on them.”

    http://neo.jpl.nasa.gov/neo/target.html

  36. If this becomes the new scare there is an obvious benefit. Assuming that funding will be switched from the CAGW scam, the money that is wasted on asteriods is better spent as it does not have the green-left communism agenda attached.

  37. You mean…. That it is ‘much worse than we expected’?

    Puhlease!

    Blind luck has certainly worked darn well for millennia. Just what do we expect climate bozos er, mental midgets to that’s better than blind luck?

    Take a look at this picture ‘Asteroid Flybys’

    Take a close look at where Earth’s orbit is and where the highest density of object crisscrosses are. Earth is obviously our solar systems trash collector.

    For more amusement, fire up Google Earth and then start scanning for circular crater images. If you need a good place to start, start your searches around Sudbury, Canada and it’s near environs.

    I’ve looked extensively using Google Earth around USA’s mid-atlantic regions and can hardly locate any craters. When I compare that area to the Sudbury area with pock marks all over the landscape I have to wonder if there are trajectories that make certain areas of Earth more likely to be on the receiving end of space junk.

    Enjoy!

  38. One of the few things the IPCC did not claim for ‘global warming’ is that it caused more asteroid strikes. Presumably that must have infuriated Greenpeace and Friends of the Earth.

  39. Ahhh Folks?

    Before you all get your knickers in knot and do the chicken dance, may I remind you that there was a Bruce Willis movie in which he and Clint(?) saved the earth from just such a rogue asteroid?

    So in the event that such a possible disaster does arise, we have saviors waiting in the wings.

    No problemo! Hollywood will save us.

  40. Peter Miller
    April 19, 2014 at 8:20 pm
    says:
    “One of the few things the IPCC did not claim for ‘global warming’ is that it caused more asteroid strikes.”

    Don’t bet on it. Ok, it may not necessarily be the IPCC but there actually have been ‘scientific’ (a word with many definitions) studies claiming global warming causes more asteroid strikes. Here’s the reason: Apparently global warming causes a thermal expansion of the atmosphere thus making the Earth and its sky a bigger target for those rocky buggers as the Earth zooms through space. And I promise I am not making that up.

    Now, if I told you that global warming would upset the gravitational fields from the black hole at the center of the galaxy, that would be something I would be making up. But, then again, who knows? I’ve actually read theories that claimed global warming would make the whole planet blow up; as in pow, kaboom, ballooey.

  41. “Latitude says:

    April 19, 2014 at 4:39 pm

    How much space stuff is actually falling on us?”

    About 40,000 tons per year. Some ice cores have “space dust” in them that date back 30,000 years or more. So we can safely assume that ~40,000 tons has been falling to earth every year for as long as there have been modern humans living on this rock.

  42. “””””…..James the Elder says:

    April 19, 2014 at 5:34 pm

    CodeTech says:

    April 19, 2014 at 4:38 pm

    Darby, compared to Win8, Vista was great.
    ====================================

    Google “Classic Shell”, Makes W8 look like W7 or even XP. Much easier to live with W8 now……”””””

    Well after having to set up a new laptop computer with Win-8 on it, and having to do it in a French speaking country, so that someone who cannot speak, could use it to communicate to others, I wouldn’t recommend win-8 even as a means of dissipating electric energy.

    I spent almost a week erasing and removing some huge number of so-called “aps”, seems like about 400 of them, before I finally had something like an operating system that worked.

    But win- 8 is a product of sheer genius, compared to Bill Gates’ crowning achievement, as a business executive. That work is Micro$oft “Excel”, that evidently was written by a couple of white Orpingtons, tapping on a keyboard with their beaks, in response to being showered with organic rice.

    The “discipline”; and I use that term loosely, that acts as a substitute for mathematics, in Excel, is best described as “quaint”. It makes “common core” mathematics, something to lust over.

    The common number of about 3.14159265359..is addressed in Excel, as ….PI()….., and to write the simple Cartesian equation for an ellipsoid, one has to write :-

    power(x,2) / power(a,2) + power(y,2) / power (b,2) + power(z,2) / power(c,2) = 1

    You would think that a couple of chickens, about to be plucked for a 4H club lunch snack, would be inspired to come up with something more intelligent than that.

    And Gates has been peddling this packaged garbage for about four decades, and evidently still hasn’t hired anybody who is trained in mathematics.

    I think Win-8 was written, to use up M$’s remaining CDs and DVDs, in preparation for their going out of business sale.

  43. Well I repeat what I said on another thread, if a large object coming from the sun, can not be spotted until it is almost on us? THEN no government or maybe some would be stupid enough to,will let the people know that they are likely to die in a few days. Can you imagine the panic?
    Runs on banks, food stores, stealing and attacking people. They will only tell us when it misses us. But just wait now for another loony cult to arise like before, and people building shelters.

    I told one lady representing my insurance company, after I queried how much my house and contents has risen, and why. “Bushfire, floods and tsunami insurance” Well I said, ok, for the bushfire levy, even though it won’t happen here, floods, I don’t live near the sea or a river. But tsunami, come off it! I live 3,500 ft above sea level, and should that be effected it would have to be a big bleedin’ asteroid to crash in the TASMAN sea, and then non of us would need insurance any more.” She hung up on me, but I argued again, and they reduced my insurance $600 a year.

  44. I totally agree with Charles Nelson – “seriously though…these little fellas have been doing this since for ever. We mustn’t confuse the ubiquity of camera phones etc etc with increasing frequency, we’ll be seeing lots more of this type of thing.”

  45. This just another MMS thing they can grab hold of and run with. Next it will be asteroids cool the planet, probably do if they impact. Look at Russia last year.

  46. Asteroid or comet collision avoidance involves interception and deflection of a sizable object which has been accurately tracked and determined to be on a collision course with the earth. Threat objects are a few kilometers in size and would be deflected by detonation of a nuclear device of a few megatons weighing a few thousand pounds. The most stressing objects driving the rocket delta velocity requirements are comets which have an icy conglomerate structure and undergo unpredictable accelerations due to outgassing when they pass close to the sun. These unpredictable delta velocities can place the comet on a collision course with the earth on the outgoing leg of the comets orbit about the sun. Thus the warning time may be as short as 30 days or so. The velocity requirement starting from low earth orbit is about 60,000 ft/sec but the acceleration requirement is only about 1 ft/sec/sec. Given the large velocity requirement but low acceleration requirement (starting from low earth orbit) this would appear to be a good application of nuclear powered rockets. And, it is interesting to consider how the nuclear rocket power supply could be incorporated into the nuclear device payload. This mission will require not just Rocket Scientists but Nuclear Rocket Scientists!

  47. In partnership with Ball Aerospace, the B612 Foundation will build, launch, and operate an infrared space telescope to find and track the hundreds of thousands of threatening asteroids that cannot be tracked with current telescopes. See the mission page here

    They are going to do it on voluntary donations, no taxpayer’s money is involved. I like that.

  48. Russia has had another explode recently above Murmansk. I heard an astronomer from our nearby telescope in Cootamundra I think, (near Dubbo anyway, in the Warren bungles, (I am suffering low brain outage at this time) that they were removing grants for this type of observation and warnings against impending near misses. This was quite a few years ago mind you. He said, if a large missile was coming from the sun, we don’t have much time as we only have days we can detect it.

    Anyway have a nice Easter folks, my dogs are driving me mad as it is past their meal time, and I am hungry too.

  49. [ “The goal of the B612 Sentinel mission is to find and track asteroids decades before they hit Earth, allowing us to easily deflect them.” ]
    [ “The mass of the object was about 10 thousand tons. It struck the atmosphere moving at about 40,000 MPH (more than double the speed of the Space Shuttle).” ]

    Where’s Superman when you need him ?? (probably getting Lois Lane to polish his Kryptonite)

    We desperately need the IPAD (Intergovern-mental Panel for Asteroid Deflection) operators to plug in their APPS (Absolutely Pi$$ Poor Sh!t) & develop an ‘Al Gore rhythm’ so WE can make some money out of this….(having missed out on the AGW scam).

  50. “Well I repeat what I said on another thread, if a large object coming from the sun, can not be spotted until it is almost on us? THEN no government or maybe some would be stupid enough to,will let the people know that they are likely to die in a few days. Can you imagine the panic?”

    Well, a rock 1 km or more in diameter is unlikely because they are rare and because we have found over 90% of them:
    ” With over 90% of the near-Earth objects larger than one kilometer already discovered, the NEO Program is now focusing on finding 90% of the NEO population larger than 140 meters. In addition to managing the detection and cataloging of Near-Earth objects, the NEO Program office will be responsible for facilitating communications between the astronomical community and the public should any potentially hazardous objects be discovered. ”

    http://neo.jpl.nasa.gov/faq/#purpose

    So it was estimated there could be over 1000 space rock over 1 km, but there is a lot bigger than 140 meters.
    ” How Many Near-Earth Objects Have Been Discovered So Far?

    As of April 09, 2014, 10911 Near-Earth objects have been discovered. Some 862 of these NEOs are asteroids with a diameter of approximately 1 kilometer or larger. Also, 1465 of these NEOs have been classified as Potentially Hazardous Asteroids (PHAs). ”
    PHAs are rocks the cross our orbit.

    So I so odds favor something like 100 to 200 meter diameter rock, which if hit ocean [likely] will have global effects from Tsunami, but with hours of warning before it hits, would save many lives. It should take more than hour after impact to reach most of area it will effect. But it seems at moment it’s a good possibility such rock will have more than days of warning time.
    But if mean 20 to 50 meters- which will destroy a city with unlikely direct hit, seem unlikely we detect it before it impacts. There has been such smaller rocks which have been detected before they hit earth. But unless we track it for days before hand, even then it unlikely one know if it would hit city- one could only know what general region it will hit.

  51. Berényi Péter says:
    April 20, 2014 at 12:28 am
    I’m all in favour of pure scientific research.
    Such mapping would give us a better idea of the mechanism of the origin of the solar system.
    It may also help the science community gain credibility for pure research that my assist us to measure real threats.

  52. More money-grubbing. If a city has not been wiped out in recorded history by a space rock, it is not likely to happen in the next 100 years. By then, we will have something at hand to deflect the things. Don’t worry about it.

  53. We must act now. Just over a year ago we had this near miss. What if it his Washington? New York? San Fransisco? We must apply the precautionary principle and act now! It’s an insurance policy dontcha know.

    BBC – 15 February 2013
    Asteroid 2012 DA14 in record-breaking Earth pass
    An asteroid as large as an Olympic swimming pool has raced past the Earth at a distance of just 27,700km (17,200mi) – the closest ever predicted for an object of that size.

    It passed far closer even than the geosynchronous satellites that orbit the Earth,……

    http://www.bbc.co.uk/news/science-environment-21442863

  54. MarkG says:
    April 19, 2014 at 4:01 pm

    “And since a large meteor is a REAL civilization ending event, we must do it.”

    1. It won’t be such an event in a hundred years, since we’ll have plenty of people living off Earth by then (or have wiped ourselves out).
    2. The odds of a city being destroyed by a meteor in the next hundred years are minute. The odds of civilization ending in the next hundred years due to a meteor impact are barely worth thinking about.

    What if one hit the Sahara? Global cooling? It does not have to his a city directly. What if one hit the British Chanel? Tsunami? I don’t know what will happen but we MUST ACT NOW, JUST IN CASE! Just like with global warming.

  55. charles nelson says:
    April 19, 2014 at 5:52 pm

    What are the chances of a meteorite taking down a commercial jet?

    =================

    Zero. A meteorite is already on the ground.

  56. “over 90% of the near-Earth objects larger than one kilometer already discovered”

    Curious. How can you count that which you haven’t discovered?

  57. “26 multi-kiloton nuclear-sized explosions since 2001″? Meh. That’s nothing. “Climate science” tells us that we’ve accumulated the equivalent of over 2 billion hiroshima bombs going off on our planet since 1998, thanks to nasty, evil “carbon”.

  58. I had a punnet if cherry’s from Italy.
    There were 26 in it ,coincidence I thought.
    As that is the date of the day I was born.
    I ate the cherries and saved the stones.
    Throwing the stones at the back of an orchard I had planted.
    Of the 26 stones one flourished and has grow into a young tree.
    The tree flowered this year for the first time.
    I may get to cherry pick before being extinguished by an large rock from space.

  59. Asteroid impacts and solar-flares fit nicely to a Pareto Distribution, along with the Big Bang (as an extreme) and the Carrington Event.

    This Pareto Distribution is populated by Black Swans for those advocating robust infrastructure systems.

  60. Alan Robertson says: April 19, 2014 at 3:27 pm “…allowing us to easily deflect them. ________________ Sure.”

    Oh, well said, on many levels! The Jewish are being told to flee the Ukraine. George Santayana was a seer.

  61. As someone pointed out this is unlikely to get a lot of traction from the Global scare industry because the focus is so narrow it can’t be milked by too many hanger-on parasites. A large amount of the money would have to be used for actual physical material. Not nearly as profitable as intellectual constructs.

    On the other hand. I support the idea of instigating a large scale program to build the resources needed to detect and possibly deflect such perils. The reason is that the spin-off befits would be enormous.

    We are talking actual engineering, which almost has to result in real-world applications.

  62. agfosterjr says:
    April 19, 2014 at 5:36 pm

    Not necessarily. No matter how any heads you toss, chances of next tossing tails remain 1/2. Asteroid collisions would first need to be shown to be of non-random frequency to make such a claim, and your 35mya collision goes against the usual 100my or so frequency claim. –AGF

    ========================================
    I’ve read that impacts are more likely as the Sun passes thru the galactic plane about every 35 million years. Passing thru the plane (densest part of our galaxy) perturbs objects in the Ort Cloud as possibly the K belt too. Some of these perturbed objects make it to Earth. Hence an apparent lose link to a 35 million year period for big impacts.

    ===============================

    http://curious.astro.cornell.edu/question.php?number=402

    “The period of oscillation in and out of the plane of the galaxy (up and down) is about 70 million years. This means that we pass through the Galactic midplane about every 35 million years which some people have compared with the period between mass extinctions on Earth to come up with yet another doomsday theory.”

  63. Probably the best sci-fi treatment of this subject is Lucifer’s Hammer by Larry Niven and Jerry Pournelle, available on Kindle.

    The book deals extensively with both the pre and post event fun in a scientifically accurate way (mostly). In their case a comet is detected on a near miss trajectory. However, it comes out from behind the sun breaking up and the rain of fragments makes a really bad day for everyone. Widespread forrest fires, tsunamis, etc. The second half deals with the following years of very cold weather and how the survivors self-organize after the end of civilization as we know it.

    A great read.

  64. peter says:
    April 20, 2014 at 6:51 am

    On the other hand. I support the idea of instigating a large scale program to build the resources needed to detect and possibly deflect such perils. The reason is that the spin-off befits would be enormous.

    ==============

    It’s all good ’til Ernst Stavro Blofeld gets his hands on it.

    Throwing taxpayers’ cash at something with the belief that the payback will exceed the cost is naive at best. That’s not how investment works.

  65. Wouldn’t one expect the number asteroid impact threats to have decreased over geological timescales?

    Don’t the objects get used up while new objects are not being created?

    One less thing to worry about => the risk is self-eliminating.

    John

  66. That’s not news to those in the business of watching space. DSP has been seeing that kind of activity almost since it was implemented. And I do recall a news item from the 1970s that involved a civilian cargo aircraft flying between Tokyo and Anchorage. Somewhere out over the north Pacific Ocean they watched a mushroom cloud rise from the sea surface. Being unsure as to what it was, they circumnavigated it. Radiation test done after landing at Anchorage revealed NO radiological contamination.

  67. I can build a computer model to study the probably of asteroid strikes and the extent of the damage. It will settle the science. Please send money.

  68. The spin off technology from implementing a program for protecting ourselves from killer asteroids would benefit mankind in more ways than one. A mission sent to these things would not only involve diverting the trajectory of asteroids from a collision from Earth but also would supply the means for setting up facilities on high valued targets for resources extraction. Gaining control of asteroids is the natural next step for mankind if we are to safely develop the solar system and raise our chances for survival.beyond the confines of the Earth.
    Once a asteroid protection system is in place it would render nuclear war obsolete as it would involve orbital based high powered lasers that could also vaporize missiles before they could hit there targets. In saying this It is very important that this be a joint project between all governments of the world to avoid a global totalitarian dictatorship as a private entity would surely use this as a super weapon to force its rivals to submit to their power. I am expecting astroid defence to become more of a issue as NATO and its allies continues to squeeze Russia and China into confrontation as total nuclear annihilation is not a option for all sides. A private entity must not be at the controls of a asteroid defence system or we will be guaranteeing ourselves slavery into the space age.

  69. “In saying this It is very important that this be a joint project between all governments of the world to avoid a global totalitarian dictatorship as a private entity would surely use this as a super weapon to force its rivals to submit to their power.”

    Yeah, like the UN is doing a great job keeping Russia out of Crimea.

    And the U.S. has to get rides into space from the Russians.

    BWTM . . . Man Made Global Warming is a product of this joint project between all governments.

  70. Bill Ills says

    The question becomes what do we do about the large asteroids that we find. If it is 3 kms wide, do we just take the impact. Easier than 50 smaller impacts causing wide-spread devastation. We have to make sure all the parts miss the Earth. If it is 10 km wide, we better try to stop it. Only people living in mines for 5 years would survive this size. But we don’t want to turn a 10 km impact into 10000 smaller impacts. We still don’t know what the best solution is.

    You seem to assume that deflecting an asteroid must be a violent affair. This is not true if the collision is foreseen early enough. Then a gravity-tug mission is practicable which will not cause even the most fragile asteroid to break up0.

  71. tty says: April 20, 2014 at 12:48 pm “You seem to assume that deflecting an asteroid must be a violent affair. This is not true if the collision is foreseen early enough. Then a gravity-tug mission is practicable which will not cause even the most fragile asteroid to break up0.”

    Modus ponens much? Affirming the antecedent of early-enough. The technologic infrastructure to deflect a visible mass, let alone “gently” and accurately and remotely is not even practicably forseen.

    Compare and contrast the deflection of ISS-1 Blackhole in its failing orbit, or of the infinitely more valuable HST.

  72. John Whitman says:
    “Wouldn’t one expect the number asteroid impact threats to have decreased over geological timescales?
    Don’t the objects get used up while new objects are not being created?
    One less thing to worry about => the risk is self-eliminating.”

    It’s not that simple. Impact rates were very high early in the history of the solar system, but since the end of “the Late Heavy Bombardment” 3 900 million years ago impact rates seem to have been fairly constant.
    Generally speaking planets will ultimately “sweep up” objects that intersects their orbit. However the population of orbit-crossing objects is occasionally replenished by collisions between objects in the asteroid belt. For example we know that such an event – the breakup of the so called L-chondrite body happened about 470 million years ago, followed by huge wave of meteor impacts of every size on Earth.

    The last major generally recognized “impact swarm” happened near the Eocene/Oligocene border c. 35 million years ago when at least 4 major impacts occurred over a geologically brief interval (Chesapeake Bay, Popigai, Wanapitei and Mistastin).

    Similarly the population of comets is thought to be replenished at irregular interval by stars that pass relatively close to the solar system and perturb objects in the Oort cloud into orbits that take them into the solar system.

    It should be noted that we only know a very small proportion of even large impacts that have occurred. New craters – even large ones – are constantly being found on the c. 20 % of the Earth’s surface that is accessible.
    The major part of the Earth’s surface – the ocean bottoms – is constantly renewed, and is nowhere older than 200 million years, so the vast majority of all impact scars are long gone..

  73. bom says:
    April 20, 2014 at 8:24 am

    The devastating Chesapeake Bay impact, which sent a megatsunami washing over Camp David, was off by just 35 million years.

  74. Well, we have experienced the Tunguska event over Siberia only 100 years ago. Certainly “earth-shattering” had it been only a two kilometers closer!

    Then Jupiter got hit by the 26 comet remnants only 20 years ago.

    The moon gained a visibility-striking new crater only last year. City and state-sized blast zone.

    And now the last few.

    Yes. A city-sized impact IS likely.

    ——-

    SO, how to deflect a medium asteroid/comet?

    The “community” has a complete absolute “you can’t use a nuclear weapon” attitude based on their prejudices, but persistently claim that mythological wands like an ion engine (that does not exist) or a solar-screen “sail” or a “gravity attractor” would work. Somehow.

    Yet, none can criticize the simple fact that a close-burst nuclear weapon (or one bursting on the surface (not drilled underneath the surface as in the recent movies) would break apart the comet or asteroid, and what pieces remain would have a slightly different trajectory. Those pieces still impacting would be smaller, and more would break up higher in the atmosphere.

    A “best solution”? No.

    But better than magic wands fueled by unobtanium and fastened to a rapidly spinning huge mass by miraculenium to create forces on a spinning mass in space at distances further than Mars? Yes.

  75. If an asteroid HAS to hit a city, please let it be Chicago. Be sure to warn me first….

    Seriously, I think the devastation caused by a massive solar flare & CME event would be far greater and longer lasting than a single asteroid, unless it was a huge honkin’ one. I believe the likelihood of a solar flare/CME is very strong, considering the quiet sun we’ve enjoyed.

    Also, an asteroid would kick up a huge amount of dust, causing global cooling, so we’ll be happy to have all that GHG in the atmosphere under that scenario.

  76. RACookPE1978 says:
    April 20, 2014 at 1:54 pm

    Yes. A city-sized impact IS likely.

    ——-

    SO, how to deflect a medium asteroid/comet?

    =======================

    No city has had a significant impact in thousands of years. “A city-sized impact IS likely.” Yes, some time in the next 10,000 years. We need do nothing, as the odds are remote.

  77. Hmmm, what cities have been destroyed over the eons by these 26 multi-kiloton nuclear sized explosions? None I believe. Luckily, big cities represent a less than 1% area of the earths surface. But the prospect of a lethal sized asteroid is a possibility, and the funds spent on “climate disruption” would better be spent on “rocket technology” able to divert the trajectory of these killer sized rocks…

  78. Doug Huffman says:
    April 20, 2014 at 6:04 am

    “Oh, well said, on many levels!”
    _____________________
    You do realize that you are not hiding under a basket (bushel)…

  79. “Athelstan. says:
    April 19, 2014 at 5:23 pm

    The catastrophe that will wipe out humanity is unlikely to be man made – naturally.”

    ====================

    Yes, you are correct, it will be man made; it will for sure beyond any doubt be a result of robots that we build. In no less than maybe one or two hundred years our future robots will exterminate mankind just like in the movies except this will be reality not just special effects.
    It all comes down to survival of the fittest, that is the way natural selection has worked in the past, continues to this day and forever into the future. The good news is that these machines will survive any large-scale asteroid impact regardless of what such impact might do to the world’s climate, yes survival of the fittest for sure and as Athelstan mentioned, “naturally”.

  80. I’m all for spending a little money on identifying and tracking potentially hazardous asteroids, if we can get to the point where we know where they will hit. With sufficient warning, people might have some time to get the heck outta the way. That’s a whole lotta ifs though, and I’m not sure how much money would need to be spent to be able to predict an impact site.

  81. It sure makes that 350 PPM thing look insignificant. It just goes to show how
    important it is to have an atmosphere. The Moon is riddled with impact craters,
    while our atmosphere defends us against all but the worst of threats.

    It would seem to me that regardless of mass, the greater threat is an air-burst
    rather than an actual impact, for the same reason a nuclear air burst is more
    devastating than any similar device detonated at ground level.

    While an event over a major population center would kill a whole bunch of people,
    an air burst would mitigate any “Nuclear Winter” scenario. It would cause damage
    over a wider area, but with less atmospheric impact.

  82. Agfosterjy
    I did not say the probability of meteor impact P = 1. I mean the probability is higher now than in other periods. Let’s estimate the value of P = probability of big meteor impact this century. Using the observed frequency of once every 10 million years, we can assume the function is a random variable with central tendency to cycle every 10 million years. Since random variables follow the normal distribution, we can assign 2-sigma deviation = 10 million years. From the z values of the normal curve, we can calculate P when x = 100 million years or more and dx = 100 years. P = 8 x 10^-6 or one in 125,000.

    How likely is that? Let’s compare it to a natural disaster like typhoons. Haiyan was reportedly the strongest typhoon to hit land. It killed over 6,000 people in the Philippines. It is one of the most typhoon-hit countries in the world. About 20 typhoons hit the country every year. The typhoon mortality rate in the Philippines is one in 135,000. Therefore, earth is more likely to be hit by a giant meteor than for a Filipino to be killed by typhoons.

  83. Gamecock says: April 20, 2014 at 5:23 am
    “over 90% of the near-Earth objects larger than one kilometer already discovered”

    “Curious. How can you count that which you haven’t discovered?”

    Start counting, and cataloguing. At first all objects are new, then you will be rediscovering objects already catalogued. Your graph of NEOs larger than 1 km against time will rise steeply at first, and then the slope will decrease. Eventually you will reach a stage where you can fit a curve to the rate of discovery. With this curve you will be able to calculate the level of the asymptote to which the curve is rising – this is the total number of NEOs fitting your parameters. Presumably those who are doing the counting have fitted such a curve, and reckon that on their calculations the total number aklready discovered is more than 90% of the asymptote level.

    Mind you, they could be wrong, but I would say their chances are better that several orders of magnitude that the CAGW people are right.

  84. Correction: I was looking at one-tail z values. It should be two-tail. The probability of giant meteor impact P is one in 62,500

  85. Why the urgency to prepare for asteroid or comet strikes of low probability that we can do little about and of which we’d at least have some reasonable advance warning when we aren’t doing anything about catastrophic solar EMP events the probability of which appears astronomically higher, of which we’ll only have a couple of days’ warning, and for which we could prepare?

  86. George Howard over at CosmicTusk.com suggested some of us who’ve been looking at these things pop over here to some clarity.

    The first thing to say is that “multi-kiloton” is a bullsh**t term. Almost all of those were VERY low kilotonnage. A 1-kiloton object disintegrating (NOT EXPLODING!) high up near the top of the atmosphere is not in ANY WAY remotely city killers. Neither is a 50 kiloton one – as Chelayabinsk showed last year. So, we can rule out 50 kiloton “explosions” high up in the atmosphere right off the bat. Even Tunguska in 1908 was basically about a 10,000 long ton body that entered the atmosphere (20,000,000 kgs) – and it knocked down a LOT of trees, no easy task, and it MIGHT be called a city killer.

    As to the size of Tunguska’s blast and Chelyabinsk’s blast, almost ALL reports – including scientific papers – talk about the size of blast as the object entered the atmosphere. But as the meteors crossed the sky (see following) over 90% of the objects get ablated away. And the buggers do NOT clarify the BEFORE and AFTER conditions – IMHO an intentional exaggeration to draw attention and funding (VERY similar to global warming exaggerations). Thus, Tunguska is claimed to be a “megaton” sized air blast. Chelyabinsk is claimed in almost ALL reports to be a 500-kiloton blast. Those are based on size at entry, not size at “explosion.”

    HOGWASH. Reduce both figures by 95%.

    Tackling some comments, one by one:

    @MarkG April 19, 2014 at 4:01 pm:

    As with ‘Global Warming’, the cost of preventing such an impact would be far more than the likely cost of doing nothing. Few possible impactors could have more than local impact, and so little of the Earth’s surface is built on that most of the others would hit relatively uninhabited areas.

    The rest of the people here should know that this is basically correct, though the first part is not exactly true. Because the Earth’s atmosphere ablates (melts and then vaporizes) about 90% of the material of incomiong objects, not so much is left, and – as Chelyabinsk and Murmansk and many other bollides have shown, they basically disintegrate high up in the atmosphere. Chelyabinsk was 25+ km up, and only about 10% of the reported 500 kilotons was still intact when it did the big flare (disintegration). Without radiation, we could have Chelyabinsks all over the planet and all we would get is a lot of broken glass and cuts. That does not exactly constitute “city killers”. Chelyabinsk’s remnant meteorite weighed only 654 kg out of 7600 long tons (13,200,000 kgs) at atmospheric entry – a reduction of 99.5%. THAT is what we have, folks – a force field called the atmosphere. I will assume that the meteorite was 50% of the mass that flared (the big flare), so basically it was ~95% evaporated before that flare.

    And, in reality, that meteor did disintegrate over uninhabited land, though several villages were very nearby, especially Yetkul (Etkul) and Korkino. So the point is very well taken that the vast majority will miss cities.

    @YouSoWould April 19, 2014 at 4:04 pm:

    Given that the last extinction level event from one was 65 million years ago, I’m not going to lose much sleep over the infinitesimally small probability of one occurring within my comparative eye-blink of a lifespan.

    Before 2007 we all thought that, too. However, google the “Younger Dryas Impact Event” and you will find much about a VERY recent impact/extinction event – well inside the time of Man. Also, visit http://www.CosmicTusk.com – linked in the right-hand column here for articles, paper links, and commentary.

    Well over 30 scientists – in over 24 papers – are now on record as arguing that at 12,800 years ago an impact event occurred in North America – taking out perhaps as many s 32 species and also perhaps wiping out Clovis Man. Much forensic evidence has turned up on four continents that backs up their thinking. There is a small cadre of ill-informed and very conservative nay-sayers who keep on cherry picking the forensic evidence for flaws and who have come up with very little counter evidence. Most of what the contrarians have asserted has been shown to be categorically WRONG and poorly done science.

    The main solid argument against this impact event and its effects (the main one being the T+Younger Dryas stadial – the very last real ice age and one that has stumped biologists and climatologists for quite some time) is this: NO CRATER has been found yet. Why that should be an argument after only 1,2 or 7 years one cannot fathom, because it took 10 full years for that 65 million dinosaur killer’s crater to be found – and that wasn’t even by a scholar, but by an oil industry geologists who happened to already know about the evidence for the crater. THAT crater was 300 km across. The mammoth killer of 12,800 years ago should be somewhat smaller and appears so far to be in the Great Lakes region – but, nope, not found yet. But nobody is panicking about the lack of a crater yet. People are on it. Since it is smaller, it should take longer to find. In the meantime the forensic evidence keeps piling up.

    …more info in the next comment from me…

  87. I think I mentioned decades ago, living on a small farm near Tamworth, I was moon bathing (it is very refreshing) when the full moon is out and it is warm. I looked up to wonder at the skies, spotting the occasional satellite and suddenly there was a beautiful bomb burst (like a firework). It only lasted a few seconds. I wonder what it was, surely not the Russians (LOL) exploding bombs up there or a UFO being shot down? I asked someone years later what it was. He said a meteorite exploding when hitting the atmosphere. It must have been quite big though to make sure a display.

  88. Kiloton is a unit of measure for energy release. The Chelyabinsk event is estimated to have released approximately 460 kt of energy. This is mostly derived from air blast over pressures and the area covered. They used consideration of the altitude where the energy was released and well understood scaling laws from Nuclear weapons testing. Using altitude of energy release and overpressure area they resolve back to the equivalent explosive energy required to produce the same results under the same conditions.

    http://adsabs.harvard.edu/abs/2013GeoRL..40.3732L

    http://newsroom.ctbto.org/2013/02/18/russian-fireball-largest-ever-detected-by-ctbtos-infrasound-sensors/

    With 7200 buildings damaged and 1491 people injured from an event that occurred at an altitude of from 29.7 – 23.3 km and 40 km south of the city clearly shows that if it had been displaced only slightly so the peak energy release occurred directly over the city and at a similar or lower altitude it could very easily have caused “city busting” damage to most metropolitan areas of the world (depending some on the quality of construction and other factors).

    It was clearly a wake up call that these events are very possible. The Tunguska event leveling of trees demonstrates a huge release of energy. Tree blow down occurs at blast over pressures that are capable of totally destroying common residential structures. To achieve 90% blow down of coniferous forests you need effective wind speeds in excess of 140 mph which occur at blast over pressures of approximately 4.2 psi. Common residential construction is totally destroyed as a habitable building at between 3.5 and 5 psi blast over pressures. In short a modern city exposed to the same air blast as Tunguska would have effectively had all the conventional wood frame buildings destroyed, all windows blow out, all exterior doors blown into the building and many interior walls and roof trusses shattered over the area where total forest blow down occurred in Tunguska. The same winds would have also taken down most of the electrical distribution lines and poles over the same area.

    • @Larry Ledwick:

      “With 7200 buildings damaged and 1491 people injured from an event that occurred at an altitude of from 29.7 – 23.3 km and 40 km south of the city clearly shows that if it had been displaced only slightly so the peak energy release occurred directly over the city and at a similar or lower altitude it could very easily have caused “city busting” damage to most metropolitan areas of the world (depending some on the quality of construction and other factors).”

      Not quite so. The explosion was almost directly over Yetkul (Etkul) and Korkino, and nothing like city busting damage happened to them.

      As to your rebuttal of my air burst assertions, your first link doesn’t work, and the second one doesn’t even mention kilotons or megatons. THAT one (which I read way back in Feb 2013) talks about the moving object and its significant effects on infrasound detectors. They say they used the data to determine the flight path. Though the article talks about the “explosion” as being the largest ever detected, there is nothing in the article reflecting your own assertions about determining the blast force. They make a big point about it being a moving infrasound event. So it is an open question from that article as to where the 500-kiloton number came from. All articles I’ve ever read about the event (and that is many) talk only about the orginal size and the 500-kilotons. No mention has been included in any of them about the diminishing size of the object. If you have any, please point me to them. I am all ears.

      Perhaps the bad link does have something such as you assert?

  89. More alarmism- this time about “asteroids” which is a misuse of the term. Meteorites are not asteroids. Depleted comet heads are not, either. This post just stinks. There is a money angle to this, you can bank on it.

  90. To see the abstract you need to cut and paste the entire link, it has imbedded dots which wordpress improperly parses to break the link.

    The key sentence in the link abstract is:
    A preliminary estimate of the explosive energy using empirical period-yield scaling relations gives a value of 460 kt of TNT equivalent.

    The book “The Effects of Nuclear Weapons” Samuel Glasstone and Philip J. Dolan published in 1962, and 1977 gives detailed discussion of how the blast effects scaling laws were developed during the early nuclear testing series. It also discusses the characteristics of air blast and air blast damage and how that is modified by the altitude of the explosion.

    Damage range varies at the cube root of the energy release. The Chelyabinsk event with its documented structural damage is a valuable bench mark as it is one of the only significant events that has occurred near a modern built up city. With its low angle of approach the blast effects were spread over a considerable ground track. If it had by circumstance been a near vertical entry angle the same energy would have been concentrated and focused into a local area.

    What is more important though is how air blast characteristics vary with altitude. The Chelyabinsk event occurred at very high altitude where the energy yield is poorly coupled to air blast. If the structure of that bolide had retained its original form long enough to penetrate to a lower altitude before it underwent primary break up the energy released would have been much more efficiently been converted to blast winds and over pressure. At low enough altitude the blast wave interacts with the ground reflection doubling the blast over pressures near the ground creating a near vertical wall of reinforced blast pressures called the “Mach front” or “Mach stem”

    When the following ref talks about “scaled heights” they are referring to these scaling laws described in detail in “The effects of Nuclear weapons” where they determine a relatively simple scaling relationship between energy release and damage effects compared to a reference yield of 1 kt of TNT equivalent energy release at some fraction of height of burst or radial distance. These scaling laws can then be used to find the effective energy release from a damage effect at a known distance from an unknown energy release, or to predict expected damage from a known energy release at some distance, based on altitude and distance.

    This paper discusses the formation of the reinforced shock wave and formation of the Mach front/stem effect. Although a bolide does not have a fire ball in the same sense as a nuclear weapon detonation does it does emit a substantial portion of its energy as thermal radiation which at lower altitudes would cause serious thermal burns and the associated precursor effects mentioned in the following paper due to thermal heating of the air near the ground prior to the arrival of the shock front.

    http://www.dtic.mil/dtic/tr/fulltext/u2/a159214.pdf

    Bottom line is that air blast phenomenon from bolide explosions on break up are well within the range of air blast that have the potential to do extreme damage to large metropolitan areas. The would not normally be the “smoking hole crater” depicted in the movies because most objects break up at altitude, but could cause significant air blast and thermal pulse damage over a city wide area. It is only a matter of time that such an event occurs, and emergency planners should consider how to respond to that possibility.

  91. @Larry Ledwick –

    All relevant stuff. As far as they go.

    Four things they leave out.

    1. On a more vertical path, the air resistance and temperature rise happens more quickly, giving an entirely different and more steep temperature and pressure and turbulence curve – and a more sudden self-destruction curve. (In addition, all incoming bodies are not equal. Some are more fragile than others, some are more cohesive. This strongly affects the results.) I am surprised they did not address this and explain how it affects the height of the “explosion”. Which will happen? A lower “explosion”? A higher one? The same? I don’t know. That is their job.

    The body melts only a little at a time, on the front (leading) surface – not the entire body melting all together at the same time. The process of ablation is only happening in the front-most surface and only for a few millimeters at a time. “Fusion crusts” (google “fusion crust meteorwrongs”) on meteors only measure 1 or 2 millimeters – not much at all. When melted (ablated) droplets are pushed off the front surface by the air turbulence, they are quickly evaporated by the temperatures, evaporation very much accelerated by the velocity of the air blowing around the meteor (like a convection oven), which makes the process more efficient. The glow of a meteor is due to the evaporation of the molten droplets. We see only the outermost glow, of the front and sides (as the evaporated material flows around the outside and is quickly left behind). ALL of that glow is rocky/metallic material in gaseous state. That is material that is no longer part of the meteor. All of that material has expanded as it changes from solid to liquid, and then again to gas. The apparent size of the meteor is much greater than the solid meteor at any given moment.

    2. Contrary to most people’s beliefs, the meteor does not “explode” from something inside it, like an atom bomb or a conventional bomb. What appear to be explosions are moments when faults/cracks within the object cause pieces to break off. This suddenly exposed material makes for a suddenly larger amount of material being ablated into vapors. This happens when the internal strength of the meteor meets forces beyond its capacity to remain integral. That breakup spot is normally going to be at the front edge, because that is where the forces are greatest. The air, as you know, is massively compressed and heated by the velocity of the meteor pushing into the air ahead of it – and the inability of that air to get out of the way fast enough. It also induces massive forces upon the face of the object and massive turbulence.

    When such a breakup causes more surface area is exposed it means that we see what looks like an explosion. But there is no fuel inside to explode. ALL of the vaporizatino is on the front surface – NOT on the inside. If one defines “explosion” as rapid expansion – which is one of the scientific meanings of the term – it is all an explosion, but not in terms that people usually think of it. It is not from the inside out, but from the front side being melted and then vaporized. The entire ablation process is explosion, if viewed from the perspective of rapid expansion. (The infrasound article mentions this, that Chelyabinsk was a spread-out event, that they could read its passage through the atmosphere, because of this continuous “explosion”/expansion going on.) The flaring (three or four of them at Chelyabinsk) is the same process, only more so – when those chunks break off and more leading surface is exposed to the super-heated air.

    The final flare-up was apparently when the biggest fault within the meteor was encountered: The object did a final and large disintegration. The object found in Lake Chebarkul broke apart from the rest of it, or vice versa – when the internal faulting caused many smaller pieces to break off simultaneously, leaving mostly only the lake meteorite (454 kg) to continue the main path down to the lake. The rest was strewn around along the path – those didn’t ablate completely.

    3. As most people will realize when they think about it, most meteors/bolides that have been seen and/or videoed come in at shallow angles. Watch any video – the bolides are going across the sky with many looking like they are paralleling the ground. We are left with a question: Is this the norm, or is this some artifact of our times, of video cameras? Or a variable in time because maybe in some periods lower is more common?

    Most people also think that meteors come straight out of space and all are aimed directly at Earth. Even those who study them seem to always give 45° as the average angle of entry. I do not have the wherewithal to research this, but IMHO this is a wrong assumption. I don’t know where they get it, except maybe from simply assuming that there are 90 possible degrees and they assume that all those angles are equally represented. But there is nothing in the history of meteors that indicates that in the real meteor world high angle impacts are equally represented. All that are depicted in paintings of old show objects careening across the sky almost horizontally. In modern times this seems to be the case, too.

    Instead, I submit that low angle entries are by far the most common. Why would this be so? Because the Earth has a gravity well. This is the spherical region around the Earth that anything passing through will encounter sufficient gravity and be captured by the Earth. The faster the object, the smaller the gravity well, because they can whiz to the far side of the well before their path becomes a death spiral. The gravity well is associated with the escape velocity of Earth, and is similar in some ways to a Schwartzchild radius of a black hole.

    Since the gravity well is many times larger than the Earth, the “catcher’s mitt” of the Earth is much larger than the body itself. For NEOs, the target, then is not only the Earth, but it’s gravity well. When an object is caught within it, the object begins a death spiral, down to the Earth. This gives a lower angle to the object, relative to the surface. The object will “wrap around” the planet. It’s path will be a function of both its speed and how close to the center it was aimed when it first encountered the gravity well. Just as science fiction stories and NASA space probes talk about using a planet to “slingshot” around and gain speed, the meteors try to slingshot but don’t make it. That slingshot path is a very unforgiving path; a little miscalculation is disaster. That is what happens to most meteoroids (before entering the atmosphere). Their path wraps around Earth. This must, then, lower their angle of incidence with the atmosphere.

    Chelyabinsk was at about 20°. Carancas, a meteor seen to fall in Peru, a few years ago, had a calculated angle of about 67° – more than the 45°, yes. And it made it to the ground. SOME will be greater than the 45°. How many? I haven’t the maths to determine this. Perhaps someone else will do it. It is a function of the diameter of the Earth relative to the diameter of the gravity well. And then it is a function of how out from the center the entry into the gravity well is.

    The lower the angle of entry, the longer the object is in the atmosphere, and that means a long time to ablate (melt away) and become smaller. And the higher in the atmosphere the flaring (disintegration) will occur.

    All of that is good news, actually. Why? It means that if we intercept an NEO on its way toward Earth, that if we can blast it into smaller objects the size of Chelyabinsk or smaller, we will have one hell of a fireworks display (and perhaps a lot of windows blown out). The oft-pictured idea of blowing one big object apart only to end up with many city-killers may not be true, after all. There CERTAINLY is a size below which we could endure millions of such objects. What is that size? No one has asked yet, that I know of. I am asking now.

    Some of such fragments would be blown into more wrap-around orbits, inducing even lower entry angles. Some, though, would end up aimed more toward the Earth’s center of gravity, meaning higher angles of entry. That is where the doing the math on the steepness factor comes in – what is THAT largest size (given the specific relative velocity of the main body)? If we can determine that size, then our mitgation plans will have a greater chance of success.

    In any event, the greatest defense we have against city-killers is the atmosphere itself. How it defends us needs to be known to the highest level possible, so tht we can work to help it do its job.

    All those “multi-kiloton” “explosions” are our proof that we are HIGHLY protected, though not 100%. It DOES behoove us to learn how to make up the balance. I suggest doing it so that the atmosphere can do the rest.

    4. I also submit that comparisons to nuclear blast tests should be done with some caution. Why? Because a nuclear explosion has a unique internal source of energy and a unique velocity of expansion, based in the quickness of its explosion. The “fuel” for meteors is quite different, and is, if anything, the “explosion” occurs over a much longer time span – even at the moment of the flare-up. In addition, it is still only the front edge doing the ablation/expansion, NOT the entire body. This, in itself, points to a flaw in any equating of volume to the forces that are later reverse calculated. The flare-up is an increase in the frontal area, and THAT is almost all that is being experienced on the ground.

    Without addressing the differences in the actual mechanisms, comparisons to nuclear blasts are imprecise, at best. The expansion forces going out at different velocities, for example, means that the curves will be different as measured at different distances. I’d certainly think the nuclear has a different curve. If so, then the reverse engineering of it will come up with a wrong ground zero force.

  92. Fortunately NASA is developing a manned transportation system that will reach into deep space if one is detected that would require human hands to deploy hardware to the surface of an approaching object. Otherwise there is nothing else on the drawing boards that could do the job, every other human based system is LEO only.

  93. RACookPE1978 says:
    “persistently claim that mythological wands like an ion engine (that does not exist)”

    So what is that thing that Dawn uses to change orbit? A mythological wand perhaps?

  94. Garcia says:

    “Since the gravity well is many times larger than the Earth, the “catcher’s mitt” of the Earth is much larger than the body itself. For NEOs, the target, then is not only the Earth, but it’s gravity well. When an object is caught within it, the object begins a death spiral, down to the Earth”

    Sorry but no. No object can ever arrive at Earth with a velocity lower than 11 km/s, so it won’t “spiral in”. It will come in in a fairly stright trajectory and the angle of impact depends on how far from “dead center” it hits.

  95. Steve, yes some of your observations are correct, there are differences between a true explosion as in a weapon detonation and the pressure front created by a super sonic object.

    When an object is moving at some 60 times the speed of sound it acts like a large piston and compresses the air in front of it to very high pressures creating a bow shock wave (sonic boom). As you mention, the moment the object undergoes breakup you suddenly have a massive increase in frontal area and the rate of energy transfer to the atmosphere goes off the charts, as the effective size of that piston becomes very large in a matter of a few seconds.

    That said, once the shock wave moves well away from the object it is simply just another powerful shock wave in air and behaves the same as the blast wave from a true chemical or nuclear explosion. The high pressure front does not know or care how it was created once it slows down to the prevailing speed of sound of the atmosphere at its location.

    When that shock front reaches the ground it will interact with the surface and buildings exactly as the shock front from any air burst of similar power and over pressure.

    They are not identical, but the nuclear weapon testing behavior is the best real world analog for such events which we have high quality data.

  96. The Earth has been built out of rocks ‘falling’ from space – a natural process known as accretion. This process has never actually stopped, it has simply slowed over time as the amount of rocky debris hurtling around in the Solar System has been progressively depleted. In its early stages the process was probably too intense for complex life to survive at all, but for the last billion or so years it really hasn’t caused much of a problem to complex life, apart from the occasional really big one every 100m years or so that has knocked life back to simpler forms that have had to start the whole tedious process of evolution all over again. It seems likely to me that the current extremely advanced level of evolution here on Earth is at least partly a result of the diminished frequency and severity of such catastrophic impacts, and that whilst they are still not out of the question, we probably have relatively little to worry about.

    But then, I am an optimist..

  97. thingadonta says:
    April 19, 2014 at 6:23 pm
    Their claim that the threat from asteriods is ’3-10 times higher than previously predicted’ is a data hockeystick. Sounds like a sales pitch to me.

    thingadona,
    No. This is data from a reliable system, designed to detect air detonations at nuclear weapon multi kiloton levels. The data hasn’t been ‘proxied’ or ‘adjusted’ or screwed with in any way that I know of.. Hard data is just that. Sometimes hard to acquire. Never refuted by idle speculation or ‘drive by’ analyses. If you’re in the Seattle area, why thingadonta you drop by the Flight Museum this Tuesday eve and listen to their presentation.
    Mac

  98. Larry –

    Points taken. Yes, I do agree that the nuclear info we have is the best we’ve got. So far – and maybe for a long time. That first portion, before it gets slowed to sonic, is the portion I was talking about. How much of a difference does it make? Hell if I know. But those first few thousand milliseconds there IS a lot of difference that should carry over – for example maybe a lot bigger pre-sonic shock wave front radius.

    I appreciate your feedback on the other points. When I learned about ablation, I was blown way by what was really going on. Interesting stuff.

    I AM convinced that the threat is smaller than I thought a year ago. Chelyabinsk taught me some things. For the size of the object I was REALLY surprised at the small extent of the damage. It gave me the impression that it could have been twice as big and had only minimal deaths, if any.

    I really DO think that if we could come up with a mitigation plan to pulverize to a high level that we can reduce the damage/risk immensely. We don’t have to save every life – or even every city. The big threat is not city-killer but extinction event. That Younger Dryas impact hypothesis was a big one. Also Shoemaker-Levy 9’s 20 or so fragments airbursting in Jupiter’s atmosphere in 1994 showed how huge some events can be. The largest one was about 1.3 km, with 2 or 3 more close behind, and the plumes were as large as Earth and more. Somewhere in that range of SL-9 and Chelyabinsk there is a threshold that we need to determine reliably and then plan around it. My guess now is in the middle of the range. A year ago I thought it was around 200 meters. That would be a city-killer. But that is also TEN times bigger than Chelyabinsk.

    Are those out there? Yes. Will we spot them all by the time we need to do something? I am sure we will. And then we need to continue as well as decide what mitigation is really going to do a decent job. As far as I’ve seen, we really don’t have a good enough plane yet. NASA’s puny budget doesn’t help. Dave Morrison has nothing to work with. But spending so much on Mars is NOT helping.

  99. Jim Butts says:
    April 20, 2014 at 12:21 am
    …….. Given the large velocity requirement but low acceleration requirement (starting from low earth orbit) this would appear to be a good application of nuclear powered rockets. And, it is interesting to consider how the nuclear rocket power supply could be incorporated into the nuclear device payload. This mission will require not just Rocket Scientists but Nuclear Rocket Scientists!

    Jim,
    Right on target! In the process of this development activity, we create the nuclear powered rockets we must have, if we hope to have humans on Mars or in the asteroid belt within the next 30 years. We need rockets that can accelerate continuously to the trip midpoint and then decelerate continuously to the objective, if we are to have reasonable travel times (~ 6 to 7 months) for the trip to Mars orbit. Note that the continuous accelerations will help the ‘MarGoNauts’, because it reduces the documented muscle and bone loss experienced by astronauts in unaccelerated space flight of months long durations…. and gets them there years before they would arrive by conventional chemical rockets that rely on traditional but inefficient ‘burn and coast’ approach.

    Let’s focus our AGW misled friends false concerns to a small but real, verifiable threat to humans and all species on the planet Earth. Many of our friends already have the ‘dinosaur killing asteroid impact’ meme embedded in their psyches. Let’s redirect the AGW bloated budget fantasia to a small but very real threat to humanity…. and spend that damn misspent AGW money on a nuclear rocket development program that serves multiple purposes!

    It’s time for mankind to take those first toddling steps away from the home crib….. and raiding the AGW funds to do it would be Ohhhhhhh, Soooooooo Satisfying!
    Mac

  100. peter says:
    April 20, 2014 at 6:51 am
    …..On the other hand. I support the idea of instigating a large scale program to build the resources needed to detect and possibly deflect such perils. The reason is that the spin-off befits would be enormous. We are talking actual engineering, which almost has to result in real-world applications.

    peter,
    ++10! This is the point! This is why we must focus the general population’s attention on small but real threats to the planet. The Shoemaker-Levy planetary bombardment on Jupiter July 1994 illustrates this well. Much more on that topic here: http://www2.jpl.nasa.gov/sl9/

    The development of nuclear rockets alone would yield many spinoff applications, not the least is the energy dense and long life nuclear rockets we must have for manned exploration of our solar system in the next 50 years.
    Mac

  101. I don’t know and correct me if I am wrong, but would a nuclear or many nuclear rockets be enough to deflect a huge asteroid from hitting earth, or deflect it towards the moon? If it broke up into many pieces wouldn’t that bring contamination into our atmosphere? This is the larger pieces that broke off hit the earth anyway? I suppose we will never know?

    • bushbunny –

      As little as they’ve been able to work on this problem (NASA is always very low on $$$), I assure you that all those questions have been asked by those studying the possibility. Quite a number of possible deflection scenarios have been looked into, including nukes, hitting a body head on, solar sails, all kinds of stuff – some less feasible than others. And they also have asked what about the radiation.

      As to larger fragments still hitting the Earth, that is a major concern, so you are asking the right questions.

      Personally, I’ve written to them suggesting a nuke option in which they simultaneously nuke it on both sides and on top, too, to pulverize it all as much as possible. Smaller fragments are much less dangerous. What constitutes small enough? That would be the $64,000 question.

      The big problems are four-fold: If we get insufficient warning is one. One other is if we get NO warning. The third is if it is just too damned big. The fourth is if it comes before we are prepared. All of those apply only to ones that we NEED to stop – big ones. As time goes on, we will learn more and more and be able to address the questions better and better. Right now we are only in kindergarten – almost no experience with that world and pretty green behind the ears. But not TOTALLY. And we have good tools and minds to put on them.

      The global warming scare has been robbing a lot of scientific fields of money for about 25 years now. This impact thing isn’t the only scientific problem going begging for money. This one is so much more potentially devastating, even if we don’t understand our risk just yet. Or lack of risk. Certainly with objects hitting the planet every several months we keep getting reminded. Russia very much sat up and took notice in February of last year. Others, too.

      As these people point out, our calculation of the frequency of these objects has been going DOWN. From Gerritt Verschuur, “Impact!: The Threat of Comets and Asteroids,” in 1996,

      Compared to estimates made in the past century, one thing has changed in recent years. The NEAs have entered the picture and therefore the odds of impact have shortened dramatically. Around the end of the nineteenth century the odds had shortened to once every 10 million years or so, which held until the early 1980s when 100,000 years between civilization-destroying impacts began to surface. That change happened because of the sudden increase in information about NEAs, crater statistics, and past mass-extinction events. A spate of at least nine estimates appeared in early 1995, four of which independently set the interval between such collisions at close to 5,000 years.

      From that book, Hills and Goda are quoted,

      With the present efforts with Spacewatch, it will take 50 years or more before we know the ones that can destroy our society. The [asteroid size] boundary is somewhere around 1 kilometer, depending on its composition. With a metallic object it can be as small as two tenths of a kilometer.

      That was what we knew as of 1996. Those numbers are pretty close to what I thought one year ago. We are about 1/3 of the way along that timetable. We should know 1/3 or more of them by now. And we do. Progress is being made. SOME articles like this one are useful in keeping SOME funding going. (Damn that global warming, anyway!)

      We are looking. We are planning a mitigation scenario, and we are realizing more and more what the real risk is. We aren’t there yet, and with a reasonable amount of funding and effort we will continue to size up the realities. The odds are very much in our favor that we are beginning soon enough and will have a workable plan long before we need one.

  102. Steve Garcia says:
    April 21, 2014 at 12:41 pm
    ……The body melts only a little at a time, on the front (leading) surface – not the entire body melting all together at the same time. The process of ablation is only happening in the front-most surface and only for a few millimeters at a time. “Fusion crusts” (google “fusion crust meteorwrongs”) on meteors only measure 1 or 2 millimeters – not much at all. When melted (ablated) droplets are pushed off the front surface by the air turbulence, they are quickly evaporated by the temperatures, evaporation very much accelerated by the velocity of the air blowing around the meteor (like a convection oven), which makes the process more efficient. The glow of a meteor is due to the evaporation of the molten droplets. We see only the outermost glow, of the front and sides (as the evaporated material flows around the outside and is quickly left behind). ALL of that glow is rocky/metallic material in gaseous state. That is material that is no longer part of the meteor. All of that material has expanded as it changes from solid to liquid, and then again to gas. The apparent size of the meteor is much greater than the solid meteor at any given moment.

    Steve,
    Close but …. consider this. Approximately 95% of all meteorite remnants examined were iron-nickel bearing meteors. The metal is present in elemental form, not as metal oxides. As such, the iron and nickel are readily oxidized as temps rise above the melting point, an exothermic reaction. At the front face of a meteor entering earths atmosphere, frictional heating from the atmosphere icreases as the meteor drives deeper into it. As the front face of the meteor melts, the iron-nickel metal exothermically oxidizes, adding to the frictional heating. The deeper into the atmosphere the meteor drives the more oxygen is available for exothermic oxidation… and the more that oxygen is compressed at the front face of the melting metal meteor.

    Have you ever seen an oxygen-acetylene ‘cutting torch’ in operation on common steels, alloys of mostly iron? A ‘neutral’ oxy-acetylene flame is used to heat the metal to the melting point. As soon as the steel glows ‘white hot’ incandescent, an extra stream of pure oxygen is added to the heating flame initiating a rapid oxidation, high heat yield exothermic reaction. The added exothermic heat combined with the pressurized feed of oxygen rich gas into the melting iron creates the conditions that allow rapid thermal cutting of thick steel plate. Multiply this mundane industrial process by the pressures at the face of a iron-nickel meteor entering Earths oxygen rich atmosphere at 16 to 28 kilometers per second. Think “biggest friggin’ cutting torch you can imagine” and multiply by 1000………

    It isn’t just ablation, melting, and vaporization ‘going on’……. and this can lead to unpredictable break ups in metal rich meteors that greatly enhance the expansion of the meteor effective diameter and the corresponding pressure/shock wave.
    Mac

  103. Mac the Knife –

    You seem to have the iron meteor percentages backward. Only 4.4% are iron, 94.6% are stony, and 1% are stony-iron. http://en.wikipedia.org/wiki/Meteorite_fall_statistics

    As a mechanical design engineer in industry I worked for years in plants with oxy-acetylene cutting departments. The pressurized secondary oxygen is also providing the velocity to drive out the slag, if I recall. In one plant we had ones that would make vertical cuts in 15″ mild steel.

    That process is fairly close to the ablation process, actually – first melt and then blow out the droplets with high pressure.

  104. bushbunny says:
    April 21, 2014 at 9:51 pm
    I don’t know and correct me if I am wrong, but would a nuclear or many nuclear rockets be enough to deflect a huge asteroid from hitting earth, or deflect it towards the moon? If it broke up into many pieces wouldn’t that bring contamination into our atmosphere? This is the larger pieces that broke off hit the earth anyway? I suppose we will never know?

    bushbunny,
    Not so much a correction as a clarification of how the systems work together to achieve a deflection of a potentially earth impacting meteor or comet.

    There are three parts to a detection, intercept, and deflection system. The first part is the search system, based on conventional radars, infrared based systems, and optical systems. The further out we can detect an earth intercepting object and predict its trajectory, the more time we have to respond effectively.

    The second part of the system is the rocket that delivers the deflection system/payload to the orbital intercept with the incoming object. The further out the object is intercepted, the smaller the impulse the deflection system must apply to the object to nudge it out of an earth intercepting orbit. Orbit here usually means a highly elliptical orbit of the incoming boloid around the sun that happens to intercept the earth in it’s orbital path around the sun. The more powerful and faster the rocket delivery system is, the farther out we can intercept the incoming boloid and the smaller the deflection payload can be. Current technology chemical rockets are relatively low energy, ‘burn for a short time, coast slowly most of the way to the object, then a short deceleration burn to match orbits’ slow delivery systems. Nuclear fission powered mass reactions rockets provide much higher kinetic energies and can provide continuous acceleration to the midpoint of the orbital intercept with the incoming object and then continuous deceleration to match orbits with the object before deploying the deflection system. It’s a potentially much faster delivery system, giving us the capability to intercept the object with a modest deflection payload further away from earth… or get a big deflection payload to an object that we detected when it was already closer in than we might like .

    The third part of the system is the deflection system. If the incoming object can be intercepted sufficiently far away from the earth, a smaller ‘push’ is needed to deflect it from an earth intercepting orbit. The closer in it gets before we can get a deflection payload to it, the bigger the ‘push’ we need to apply to move it enough to miss earth.

    Then there is the physical make up of the incoming object itself. If it is a stoney chondrite asteroid or a high metal content asteroid, we probably can use a suitably sized nuclear fission payload/warhead on the rocket to apply the ‘push’. If it is a ‘soft’ comet, made of a mix of ice and rock (the ‘hot fudge sunday of Lucifers Hammer, Niven and Pournelle), we will have to use a softer ‘push’ deflection payload to ‘push it’ without breaking it up…. or just bomb the hell out of it and accept the infall of the smaller but less lethal pieces.

    Does this help understanding of how then detection, rocket delivery system, and deflection payload systems must work together, bushbunny? This is the kind of astrophysics, astronautics, nuclear power, macro-engineering, and pyrotechnics that I really enjoy. There are few natural hazards that the creativity of engaged and driven humans cannot overcome, given the unfettered opportunity to experiment, create, and eventually succeed. This is a small but very real threat to humankind and all life on this precious little blue and white marble, third rock from the sun, called Earth. The solution is achievable and worth doing.
    Mac

  105. Steve Garcia says:
    April 21, 2014 at 10:48 pm
    Mac the Knife –
    You seem to have the iron meteor percentages backward. Only 4.4% are iron, 94.6% are stony, and 1% are stony-iron.

    Steve,
    See http://meteorites.wustl.edu/id/metal.htm for source of my info.
    As for my bona fides, I’m a two-time metallurgical engineering degree offender from UW-Madison WI, with specializations in welding and aerospace alloys, and +27 years experience in all kinds of aerospace, astronautics, missiles, and nuclear power engineering/materials applications. I was a welder and mechanic (among other things) before I ever started college, and can still handle a cutting torch, TIG welder, or oxy-acetylene welding torch today. Suffice it to say ‘Simple melting is one thing, Exothermic cutting is much more aggressive and accelerated.’

    I tipped Anthony to this topic because I very much want to shift the public awareness from the unsupported fear of AGW to real and measurable threats to the planet Earth and all its denizens. Asteroid or cometary impact is one of those small but quantifiably real threats to our ancestral Ark. Addressing it will drive essential innovations to all aspects of space exploration systems.

    Sure, there are others (vulcanism, earth quakes, tsunamis, etc) that should all have greater concern and attention than AGW also… but I chose this topic, as I really believe that man’s destiny lies out in the stepping stones of the planets of our solar system….. and then on to the stars. If we can divert funding from AGW to these applications, it is money well spent.
    Mac

    PS: I appreciate your lengthy and well informed comments on this thread and Larry Ledwick’s as well!

  106. Thanks guys, I agree, but I read an article that NASA was planning towing asteroids to orbit the moon to study them?? I hope they know their physics? Wouldn’t our gravitational pull bring them closer to us? Nice one NASA!

    • Steve Garcia said: April 21, 2014 at 12:41 pm

      “Since the gravity well is many times larger than the Earth, the “catcher’s mitt” of the Earth is much larger than the body itself. For NEOs, the target, then is not only the Earth, but it’s gravity well. When an object is caught within it, the object begins a death spiral, down to the Earth. This gives a lower angle to the object, relative to the surface. The object will “wrap around” the planet. It’s path will be a function of both its speed and how close to the center it was aimed when it first encountered the gravity well. Just as science fiction stories and NASA space probes talk about using a planet to “slingshot” around and gain speed, the meteors try to slingshot but don’t make it.”

      Thank you for your enlightening comments, Steve, but regretfully I must disagree on the above para. Agreed the ‘catcher’s mitt’ is much greater than the Earth. But, unless the thing is sufficiently close to the Earth to be slowed – by atmosphere or something else – it will keep going – behaving exactly as a comet does when it passes the Sun. It will have a parabolic or hyperbolic orbit wrt the Earth, or, depending on what may have happened earlier in its wanderings, be in an elliptical orbit with the Earth at one focus. Of course, if the elliptical orbit takes long enough, the Earth will have moved on and the shape of the ellipse will be mangled – how much I would not try to guess. But if the object comes in sufficiently close to the Earth, it will be slowed by the atmosphere, and most likely will, as shown by these recent arrivals, be heated so much it breaks up. With a flatter orbit at higher altitude, it could leave the atmosphere, but return to re-enter the atmosphere , perhaps several times – the favourite return mechanism for space craft before the development of the ablation cone protecting the front end. In this case the object will certainly be on a death spiral.

      Shoemaker Levy must presumably have already had one contact with Jupiter, which caused the original very large object to break into many smaller ones, these continuing on the same very tight ellipse which brought them back to Jupiter. If two objects have orbits that cross each other in all three dimensions, then unless the periods are exact multiples and the objects are separated when each crosses the other’s orbit, they will eventually collide. Conversely, if the orbits do not coincide in all three dimensions, they cannot hit each other as long as the orbits do not change – which will happen if there is a near miss.

      While it is plausible that the overwhelming majority of things arrive in low orbits – as Steve suggests – consider that these are the ones that last long enough in the high atmosphere to be seen and recorded. How high is the atmosphere? Say, for example, that the atmosphere extends 100 miles. – the height of low orbit satellites. In a vertical arrival, at the speed of a minimum of 11 km/s or 7 miles/s, a vertically falling meteorite will take 14 seconds to enter and hit the Earth. Plenty of shock wave, but arriving so quick it is not likely to be seen. Well, far less likely than the near horizontal Chelyabinsk meteorite to be seen.

      I am told that if you see a meteorite land and pick it up you are likely to have your hands burnt – not due to its being hot as much as due to its being intensely cold. Though I would suggest that if it had been following the earth for some time, hence at roughly the same distance from the Sun, it would have attained approximately the same temperature as the Earth’s surface would have if not for the atmosphere and the Earth’s internal heat, ie, just a bit below freezing point of water. Who knows?

  107. Mac the Knife –

    Very interesting. Yes, I am well aware of that group of wustl web pages, which I refer to as the Meteorwrongs pages. In fact, I was just emailing with Randy Korotev (who authors it) in the last week, about some possible finds in India by a friend of a friend. Small world! (I am NOT a meteorite hunter, though.)

    Yes, that page says, “About 95% of all meteorites contain iron-nickel (FeNi) metal.” If you follow the first link on that page (stony chondrites), though, THAT page says this, “Most (>95%) stony meteorites are ordinary chondrites.” Contradictory? Apparently, though this statement seems to only be talking about stony meteorites.

    This seems to be harder to find out than it would seem to be. Phrasings on some sites are not clear or they don’t mention percentages.

    For example, the National History Museum’s meteor page says, “The majority of meteorite falls are stony meteorites consisting mainly of silicate minerals.http://www.nhm.ac.uk/nature-online/space/meteorites-dust/meteorite-types/

    Okay, then, let’s go back to the wustl pages, since that is where we started out. http://meteorites.wustl.edu/meteorite_types.htm Scroll down the page to the image labeled “ALL METEORS.” The pie charts are a bit confusing, but the text below says this:

    Most meteorites that fall on Earth are stony meteorites. Only a few percent are irons. However, in populated places like North America, people find a greater fraction of the irons because irons tend to be bigger* and are more likely to catch peoples’ attention.

    *Although only 2.6% of meteorites are irons, 85% of the mass of all meteorites is in the irons. 11% of the mass is in the stony meteorites.

    That image shows pie chart that clearly states that 97.0% of “all Meteorites” are “stony.”

    Does that settle it? Actually, NO, because just below he then goes on to say,

    “Most stony meteorites are chondrites, and most chondrites are ordinary chondrites. Chondrites contain iron-nickel metal, which is what makes them attracted to a magnet.”

    His “Ordinary Chondrite” page discusses much about the metal in ordinary chondrites.

    Since the difference between 95% stony or 95% iron is huge, whenever any site says “most meteorites” I assume they are referring to THAT 95%, not the other. (If that made no sense, ignore it.)

    So it still seems unclear to me, because they seem to phrase things in ways that it is unclear whether they are talking on one hand about predominantly metal meterorites, or on the other hand meteorites that include some metal.

    So, where are we on this? Frankly, I am not sure. Maybe this: 95% of all meteorites are ordinary chondrites, which contain some percentage of iron.

    For myself, 7 years of my career I worked in R&D, doing experiments for scientists and frequently interacting with the metallurgists in our R&D center. I respect you guys. Big time.

  108. “Steve Garcia says:
    April 21, 2014 at 10:38 pm

    …. Quite a number of possible deflection scenarios have been looked into….

    The big problems are four-fold: If we get insufficient warning is one. One other is if we get NO warning. The third is if it is just too damned big. The fourth is if it comes before we are prepared. All of those apply only to ones that we NEED to stop – big ones….

    And if we get one of those relatively garden-variety Carrington events, or something just a bit bigger, every one of the above four issues will come to bear fatally, plus a fifth – if we are NO LONGER PREPARED, or even ABLE TO PREPARE.

    So wouldn’t it make infinitely more sense to deal with the Solar EMP issue before tackling the deflection issue? Or is Solar EMP not considered a credible cause of global infrastructure collapse in this forum?

  109. There have been several in depth discussions regarding Nuclear EMP and solar flare/CME events like the Carrington event. It could also be substantially mitigated at a small fraction of the cost of chasing a phantom issue like global warming.

  110. What happened to reliable computer models showing that no large fragment of a Chelyabinsk-sized meteorite could reach the ground? It should have evaporated high up.

  111. @otropogo – Interesting addition to the discussion. Yes, we should put some priority on that. In the short term it’s probably a bigger risk than an impact, which might not come for a few thousand years – maybe longer.

    Without infrastructure, we have no civilization. I am serious about that. Take it away and see how fast people starve and how MANY, right quick. EMP only targets electronics, true, but without electronics, how far back in time do we go, and how fast an we adjust and rebuild? Only as far as the 1950s?

    Without at least a PLAN, it could get ugly, real quick.

    And Larry Ledwick is right about the cost being so much less than they are talking about with global warming. In fact, in some ways the global warming thing is roughly equal to a slo-mo Carrington event – taking us back in time, costing gazillions of jobs, and starving a right lot of folks.

  112. @Dudley Horscroft 8:32 am:
    “Thank you for your enlightening comments, Steve, but regretfully I must disagree on the above para. Agreed the ‘catcher’s mitt’ is much greater than the Earth. But, unless the thing is sufficiently close to the Earth to be slowed – by atmosphere or something else – it will keep going – behaving exactly as a comet does when it passes the Sun.”

    Incorrect, Dudley. If the atmosphere slows it, it is captured already – mostly because of the AMOUNT it slows it. And what is the “something else” that might slow it? As it approaches Earth the Earth’s gravity is actually accelerating it.

    “It will have a parabolic or hyperbolic orbit wrt the Earth, or, depending on what may have happened earlier in its wanderings, be in an elliptical orbit with the Earth at one focus.”

    True, but not if it enters the atmosphere.

    “Of course, if the elliptical orbit takes long enough, the Earth will have moved on and the shape of the ellipse will be mangled – how much I would not try to guess.”

    There are programs to figure all this out. You don’t have to guess.

    “But if the object comes in sufficiently close to the Earth, it will be slowed by the atmosphere, and most likely will, as shown by these recent arrivals, be heated so much it breaks up. With a flatter orbit at higher altitude, it could leave the atmosphere, but return to re-enter the atmosphere , perhaps several times…”

    None of this is true. Though it may sound reasonable, no.

    “Shoemaker Levy must presumably have already had one contact with Jupiter, which caused the original very large object to break into many smaller ones, these continuing on the same very tight ellipse which brought them back to Jupiter.”

    If you have read even a little bit about SL-9, you know that that is exactly what happened. On its last previous close pass of Jupiter it DID break up, and the change in orbit due to that really close pass DID put it on a collision course the very next orbit.

    “If two objects have orbits that cross each other in all three dimensions, then unless the periods are exact multiples and the objects are separated when each crosses the other’s orbit, they will eventually collide.”

    This is all mitigated by the fact that most planets and asteroids and comets are are in slightly different planes, or inclination. The higher the inclination, the more what you just said is true, that they won’t likely hit. At the same time, even reasonbly close passes can throw the smaller body into god knows what orbit and inclination. Because of this effect on the smaller body, really long term orbits are not necessarily possible to predict.

    “Conversely, if the orbits do not coincide in all three dimensions, they cannot hit each other as long as the orbits do not change – which will happen if there is a near miss.”

    Your last point is what I just wrote. AS to the first one, not true at all, though it is HIGHLY unlikely. The real point is whether the points at which the smaller object crosses the orbital plane of the larger. If those are farther in or out from the larger body’s orbit – THEN it is impossible. And that is the case for most comets. For NEOs, which are affected by Earth’s gravity to some extent at all times, and which have different orbital times, there is a dance going on – specifically because the orbits DO change.

    “While it is plausible that the overwhelming majority of things arrive in low orbits – as Steve suggests – consider that these are the ones that last long enough in the high atmosphere to be seen and recorded.”

    I DO put that out there only as what sounds reasonable to me. I don’t know for sure. It is not necessary that they be in high orbits in order to be seen or recorded. Tunguska airbursted at fairly low altitude. People DID see it, though it is not recorded how low it would have been seen when they did.

    “How high is the atmosphere? Say, for example, that the atmosphere extends 100 miles. – the height of low orbit satellites. In a vertical arrival, at the speed of a minimum of 11 km/s or 7 miles/s, a vertically falling meteorite will take 14 seconds to enter and hit the Earth. Plenty of shock wave, but arriving so quick it is not likely to be seen. Well, far less likely than the near horizontal Chelyabinsk meteorite to be seen.”

    For most of this, I recommend that you simply google the topics and learn a little bit on your own. As to Chelyabinsk, the downward angle, last I heard, was 20°. It DID appear to a lot of people at CosmicTusk.com that it HAD been horizontal – and then had skipped out into space. But we got fooled. Myself, it was only when I saw video from MANY angles and ALL of them appeared to be downward that my instinctual brain accepted that it was a downward path. From the perspective of any particular video it was simply not easy to ascertain a downward angle – since the views were at skewed angles to begin with. At about that same time, someone had managed to look at one of the Chealyabinsk city videos and the shadows and determine pretty correctly about the angle. (In addition, as long as the body was in the atmosphere, technically it was a meteor. Only after it hit the surface did it become a meteorite. BEFORE it entered the atmosphere it was a meteoroid.)

    “I am told that if you see a meteorite land and pick it up you are likely to have your hands burnt – not due to its being hot as much as due to its being intensely cold.”

    Not even CLOSE to being true. The body was heated a HUGE amount by the air ahead of it, which it was compressing at a really high rate. Touch your refrigerator’s compressor sometime while it is compressing – but be bloody careful!

    In addition, I point you to gogogle the Carancas meteorite and read up on people who went to it after seeing it land.

    “Though I would suggest that if it had been following the earth for some time, hence at roughly the same distance from the Sun, it would have attained approximately the same temperature as the Earth’s surface would have if not for the atmosphere and the Earth’s internal heat, ie, just a bit below freezing point of water. Who knows?”

    In short, no. It is not the Earth’s internal heat that keeps the surface at about 15°C. It is the atmosphere and its greenhouse effect. Without that greenhouse effect, the temp would be -18°C. (If that is wrong, someone here correct me.) The greenhouse effect, then, is GOOD. Without it we would not be living on the surface (and probably not anywhere). -18°C is too damned cold for me!

  113. The net gain in technology setting up the infrustructure to protect ourselves from asteroids would have a positive effect on the economy just like the Apollo program did. Even if another meteor doesn’t hit us for another 10,000 years it is still worth it. Why do we need a impending threat to do the right things anyways?

    • Re your latest, Steve. Perhaps we are once again “separated by a common language”.
      You said:
      “Incorrect, Dudley. If the atmosphere slows it, it is captured already – mostly because of the AMOUNT it slows it. And what is the “something else” that might slow it? As it approaches Earth the Earth’s gravity is actually accelerating it.”

      Regrets I disagree again. It is only captured if the orbit is changed from hyperbolic or parabolic or an ellipse not focused on the Earth to an ellipse focused on the Earth. It can enter the atmosphere, and have its orbit changed, but still not be captured if it then departs – as far as the Earth is concerned, on another parabolic orbit. Re the “something else”? Here we enter the realm, after the “known knowns”, the “known unknowns” to reach the “unknown unknowns”. That is, what may possibly be there which could cause it to slow but which we have no idea of. Rather like Lord Kelvin, calculating that the Sun could not possibly have lasted more than 500M years, left himself a let out at the end.

      “It seems, therefore, on the whole most probable that the sun has not illuminated the earth for 100,000,000 years, and almost certain that he has not done so for 500,000,000 years. As for the future, we may say, with equal certainty, that inhabitants of the earth can not continue to enjoy the light and heat essential to their life for many million years longer unless sources now unknown to us are prepared in the great storehouse of creation.”
      (See: http://zapatopi.net/kelvin/papers/on_the_age_of_the_suns_heat.html)

      I wrote: “With a flatter orbit at higher altitude, it could leave the atmosphere, but return to re-enter the atmosphere , perhaps several times…” You added: “None of this is true. Though it may sound reasonable, no.”

      As to skip re-entry for an object, this has been done for spacecraft. While unlikely, it is feasible that an object at exactly the right angle, could have actually skipped once, even possibly more times. See: http://en.wikipedia.org/wiki/Skip_reentry

      I said: “I am told that if you see a meteorite land and pick it up you are likely to have your hands burnt – not due to its being hot as much as due to its being intensely cold.” That is what I said, reporting statements on the temperature of meteorites. In general a small body will have the outer layer heated to melt and be ablated as you say, but then the body will fall comparatively slowly through the lower atmosphere, and the outer skin will be cooled. For a 1 kg rock, say, the terminal velocity might be around 100 to 200 m/s – the lower value being a bit more than the maximum value for a peregrine falcon in a dive. After having most of the speed reduced while the outer skin was being removed, from a height of, say, 20 km the 1 kg remnant would be falling at the terminal velocity, reducing as air resistance increased. This would take, say, 100 seconds from 20 km at 200 m/s, at first through quite cold air. Pretty easy to lose the excess heat from the outer skin.

      Thanks for the reference to the Carancas meteorite – I noted the following sentence: “Most larger meteorites are cold in their bulk mass when they land on Earth, since their heated outer layers ablate from the objects before impacting.” This one was hot – or rather the result was. As a back of the envelope estimate, based on the estimated diameter of greater than 3 m, I would say the mass was about 35 tonnes. The KE liberated would render the area rather warm, to say the least.

      Finally I would say that -18C is, for most people, “just a bit below freezing point of water”.

      Best regards, Steve. I welcome your contributions. If only the CAGW mob would be so willing to discuss matters amicably.

  114. Dudley –

    Yes, I much prefer respectful exchanges. We are all on the same side, anyway! I’ve begun a few comment conversations here and elsewhere on different sides of a point and then ended up finding much common ground and new friends.

    On this, you seem to be under the impression that objects can relatively easily enter the atmosphere and then “skip” into outer space and not be captured by Earth’s gravity. Remember that even when human space vehicles want to do a skipping maneuver, first, they have to VERY carefully chose the proper velocity AND the proper shallow angle or else they risk not bouncing off at all and entering ballistic orbit – meaning that they fall toward the ground pretty quickly and directly. This is what happens to meteors that become meteorites (some – most – don’t make it all the way down). To skip means to have a too shallow entry angle, and the chances of this by an object is very small – it has to enter a very narrow annulus at close to a tangent.

    You say: “As to skip re-entry for an object, this has been done for spacecraft.”

    Actually, no, this has never actually been DONE, even though they have long ago determined HOW to do it. (I had to look this up to be sure.) See http://www.aerospaceweb.org/question/spacecraft/q0218.shtml for some nice explanations.

    You seem to also misunderstand how MUCH the atmosphere decelerates an object. The “fire” of an object entering the atmosphere is FROM that deceleration – due to the air resistence and the air itself being compressed ahead of the object, which then is what melts the droplets that then vaporize, giving the glow we see. That heating and melting and vaporizing is the kinetic energy being transformed into heat energy. If the velocity drops below 11.2 k/sec at any point in its atmosphereic contact, it’s captured within the atmosphere.

    It can also be captured by Earth’s gravity without encountering the atmosphere. To be captured is a larger subset of possibilities than just atmospheric capture (which means a death spiral/ballistic trajectory). These non-atmosphere jobbies seem to be the scenarios you are talking about. Yes? Just like SL-9 was captured by Jupiter’s gravity upon the previous close pass, when the gravity also broke it into fragments. But then those fragments still went FAR from Jupiter before returning. But they WERE captured. Even if their subsequent orbits had not been death spirals. To “be captured” by a planet means that the planet becomes the focal point of the elliptical orbit instead of the Sun. It is my understanding that that is how moons became moons, without being gobbled up by their parent planets.

    (More later – I am sleepy!)

  115. “Steve Garcia says:
    April 22, 2014 at 8:01 pm

    … EMP only targets electronics, true, but without electronics, how far back in time do we go, and how fast an we adjust and rebuild? Only as far as the 1950s?

    Without at least a PLAN, it could get ugly, real quick.”

    I’m afraid your estimation of the regression effect is a world class understatement. My fear is that the survivors would be so traumatized and brutalized by the event and its aftermath that a complete return to tribal jungle behaviour would characterize humanity – where unknown men are killed on sight, and women and children at best are enslaved. Return to the technology of the 1950s would be a pipe dream, in my opinion. If humanity managed to survive at all in a much more hostile world without the technology to navigate the toxins, it could take a thousand years or more to get back to some level of ordered civilization.

    I don’t pretend to know whether the cost of preparing for such an event would be less costly than trying to mitigate climate change or interplanetary impacts. But I do know that we’ll never come to grips with it without first having the will to realistically imagine the social impact of losing electricity for even a few months, let alone a few years, at our current level of dependency. Ideas of reverting to horsepower and buggies, home gardens and wood stoves, are sheer lunacy in the face of this threat, yet they seem to prevail among those who are willing to consider the possibility at all. The sheer number of dead, combined with the density of population and interdependency for food, fuel, and medicines, would make life a desperate struggle for survival for years to come. And whatever leaders this environment throws up are unlikely to be patrons of reason or scientific thought.

  116. If you are interested in the larger picture of what is currently unfolding the read Adam to Apophis: Asteroids, Millenarianism and Climate Change by Nicholas Costa which was published a year ago

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