From the “bigger worries than global warming” department:
Guest essay by Eric Worrall
Yet another indication that Asteroids are a far more serious threat than climate change. NASA scientists have just in the last few weeks detected a previously unknown Asteroid, a quarter of a mile across, approaching at an unusually high speed of 35km / second, which is due to narrowly miss the Earth on 31st October this year. The asteroid will only approach within 1.3 lunar distances of Earth, so this particular body poses no threat – but in terms of the scale of the solar system, this upcomming event counts as a very near miss. This asteroid is a wakeup call, a reminder of just how vulnerable we are to catastrophic impacts, and how little warning we might receive if such a threat were detected.
According to NASA;
2015 TB145
2015 TB145 was discovered on 2015 Oct 10 by the Pan-STARRS I survey. The object will approach the Earth within 0.00326 au (1.3 Lunar distances or about 490 000 km) on 2015 Oct 31 at about 17:00 UT (10 AM PDT). The asteroid is in an extremely eccentric (~0.86) and high inclination (~40 deg) orbit. It has a Tisserand parameter of 2.937 hinting that it may be cometary in nature. Its absolute magnitude of 19.8 indicates that its diameter is probably within a factor of two of 320 meters. At closest approach the SNRs/run at DSS-14 are expected to be over 20000, so this should be one of the best radar targets of the year. We hope to obtain images with a range resolution as high as 2 m/pixel using DSS-13 to transmit and Green Bank (and possibly Arecibo) to receive. The flyby presents a truly outstanding scientific opportunity to study the physical properties of this object.
The encounter velocity is 35 km/s, which is unusually high.
This is the closest approach by a known object this large until 1999 AN10 approaches within 1 lunar distance in August 2027. The last approach closer than this by an object with H < 20 was by 2004 XP14 in July 2006 at 1.1 lunar distances.
2015 TB145 could reach 10th magnitude before sunrise on October 31 for observers in North America, but it will be close to the waning gibbous Moon and probably challenging to see with small telescopes. The asteroid will be in Ursa Major at the time of closest approach. After closest approch 2015 TB145 will be a daytime object and too close to the Sun to observe with optical telescopes.
Radar observations are planned at DSS-14, DSS-13, Arecibo, Green Bank, and elements of the VLBA. Observations may also occur with the UHF radar at Haystack.
Read more: http://echo.jpl.nasa.gov/asteroids/2009FD/2009FD_planning.html
If an unusually fast asteroid a quarter of a mile across struck an inhabited part of the world, the explosion would be many times larger than the half megaton Chelyabinsk meteor explosion, which was caused by a meteor with an estimated diameter of 55 ft. The explosion would be in the 10s of megatons, rivalling the largest atom bombs ever detonated – more than large enough to devastate an entire city.
How likely is such an impact? Thankfully really large impact events are very infrequent, though multi kiloton impact events are common – at least 26 such events have been detected since 2001, mostly in uninhabited regions. But there is no upper limit to the size of an impact event, and as this recent imminent near miss demonstrates, a serious threat could arise with very little warming.
What could be done to mitigate asteroid impact risk? At the very least better monitoring systems could be deployed, to try to provide at least some warning. Chelyabinsk received no warning when it was struck by a meteor. This asteroid was only detected a few weeks ago.
With enough warning people could be evacuated from likely impact zones. Even very large threats could potentially be addressed, if there was enough time to prepare.
In my opinion it is obscene that the world is spending countless billions chasing the imaginary perils of the climate dragon, while neglecting a far more serious threat to people’s lives.
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We should be grateful that their models for simulating celestial mechanics are more accurate that their climate models.
The difference between “settled” and “non-settled” science!
Also the difference between models based on known cycles and iterative models with dodgy foundations.
You may find out that they are not that accurate at the scale climastrology pretends to foresee. You may predict the trajectory of an asteroid for months quite well, for decades and centuries, not so.
So NASA could be wrong about this one???
Discovered in 2004, the asteroid Apophis is the size of three-and-a-half football fields
“The April 13, 2029, flyby of asteroid Apophis will be one for the record books. On that date, Apophis will become the closest flyby of an asteroid of its size when it comes no closer than 19, 400 miles (31,300 kilometers) above Earth’s surface.”
https://www.nasa.gov/mission_pages/asteroids/news/asteroid20130110.html
Somebody
Ad so?
Your declarative statement is probably accurate. What is you recommendation? Don’t track anything ever? Do a better job of tracking?
Chip,
I think “Somebody”s point was that orbital mechanics is a REAL science, with true predictive capability. Even so, even those guys are shy about making asteroid collision predictions 100 years ahead.
Not so the climastrologists. Their models are dubious almost to the point of a joke, yet they’re making solemn world-ending predictions 100 years out.
The contrast between true science and fake science was his point.
We can easily plot the trajectories of near earth objects for tens of decades to centuries to millennia. The ones that are the most likely to hit are the ones who’s trajectory is more difficult to pin down. We think we know what Apophis is going to do in 2029 but a deviation of just a few km and it goes through what is called a gravitational keyhole and set it up for an impact in 2036. The folks at JPL don’t think it will happen but the possibility is high enough that they would like to put a beacon on the rock to get a better ephemeris.
Well it is also true, that we can’t do anything about either one of those possibilities.
But this object has at least been ” seen ” , so we do know it is there.
The climate catastrophe, is just some ones and zeroes that someone is reading from an X-box screen.
and it has nothing to do with cloud computing either.
g
The Climate Models are actually very accurate….
Educate yourself and watch “Merchants of Doubt”
Don’t use “They” to refer to rocket scientists and climate scientists in the same breath.
The first term refers to those who rigorously abide by the scientific method, and are the top tier in measured IQ.
Whereas people go into climate science if they aren’t competent for physics, medicine, Law, Engineering, dentistry or veterinary science.
This streaming effect is the cause of the second group’s statistical incompetence, their superstitious faith in failed models, their confusion of their politics with science, and their lack of scientific integrity. This last is demonstrated by their failure to denounce the anti-scientific abuses disclosed by climategate.
“a serious threat could arise with very little warming.”
I see what you did there.
Good catch! I missed that on the first read.
Hehehee
B612 press conference on Protecting Earth from Asteroid Impacts
Video The Threat
1. How many “city killer” sized asteroids are there? How many of them do
we currently track? How often do they hit Earth?
A “city killer” is an asteroid capable of destroying a very large city or
metropolitan area. An example is the Tunguska asteroid that destroyed
nearly 1000 square miles in Siberia in 1908. This asteroid (based on new
understanding) was likely a 30-40 meter object that released about 3-5 MT
of energy on impact (about 230-270 Hiroshima bombs). There are
approximately 1 million objects of this size that cross the Earth’s orbit, yet
we have observed and tracked less than 0.5% (i.e. < 5,000) of these “city
killers”. Objects of this size impact Earth about every 300 years on average.
(Ref: National Research Council Report on Defending Planet Earth: NearEarth
Object Surveys and Hazard Mitigation Strategies; Fig. 1, Pg. 4). This
means there is roughly a 30 percent chance of an asteroid impact with
energy greater than several hundred Hiroshima bombs somewhere on Earth
in this century.
B612 Foundation/SentinalMission, Supplementary FAQ
The largest impact crater on Earth may be the Massive Australian Precambrian/Cambrian Impact Structure with a crater approximately 600 km (370 mi) in diameter!
For the damage impact of recent major comet can do, see the Shoemaker Levy comet striking Jupiter.
Too bad the powers-that-be don’t get as exercised over killer asteriods and comets as they do about global warming.
TA
“In my opinion it is obscene that the world is spending countless billions chasing the imaginary perils of the climate dragon, while neglecting a far more serious threat to people’s lives.”
Couldn’t aggre more! Nuff said!
+1
According to CNN, Global Warming is the cause of increased asteroid/meteoroid collisions with earth. A fact not dispelled by the numskull Bill Nye, the lying by omission guy.
OMG, Paul. How stupid do you have to be to even ask the question about an asteroid flyby being caused by global warming? But now that I think about it, CO2 is so powerful it is probably affecting weather on the Sun! (do I need to add the /sarc/?)
Only for CAGW acolytes.
It isn’t that she is so stupid, it’s that the people who wrote “the question” for her to ask, prepped those words for the people in her audience who are indeed so stupid as to take their daily dose of climate fear without investigating veracity, or intent.
You may have noticed that she wasn’t interested in anything Bill Nye had to say and thus, kept interrupting him. Nye’s statement wasn’t important to the meme, the only important thing was to connect “climate change” with fearful event.
That is possibly the most idiotic clip I have ever heard. If our founding fathers knew to what depths journalism was going to fall, they would not have included freedom of the press in the Bill of Rights. Our “free press” is a joke.
Look at her mouth and facial expression in the still frame, above. That’s a “tell” that she’s lying. Her stretched out mouth indicates that she is stretching the truth and knows it. There are other facial give- aways with her, as well…
Must be a parody, nobody is that stupid
Not quite a parody, expat, I’m quite sure it’s pysop business as usual, as Alan is discussing. Like subliminal advertising, the object (in this case) is to create a subconscious association between catastrophic global warming and other sorts of more palpable catastrophic events, to generate/maintain a sense of urgency. Also to reinforce the CAWG is hard science aspect of the con, hence the siants guy, with his “this is also science” mantra.
They are acting, I say, she playing the part (modeling) of the ordinary person living breathlessly anxious in a precarious world ever on the brink of destruction, with him playing the part of a wise man of Siants, dedicated to keeping us little people safe.
“We” who grasp the basics of atmosphere/space are intended to see her as somewhat dopey, I’m rather sure, and to “gravitate” toward him, psychologically. My guess is this little “skit” was devised a few minutes earlier by Mr. Nerd, and she’s none too happy with her role in it, and was not being careful to “keep it real”, and so drifted into parody territory.
Well if we have global warming, the earth expands, and that increases the likelihood of a hit.
See how easy that is ?
g
And if the atmosphere warms, it is less dense, and the asteroid will not be slowed down as much before hitting.
Yeah, that’s the ticket…
UK news presenters are just as dumb as this. And in this instance you can not blame “the people who write the questions”.
But, whilst neither the presenters nor their economics specialist could read or comprehend a large written number, they do all tend to confidently express a range of opinions on many technical matters, including economics, climate change and renewables.
I guess that – you don’t know what you don’t know. Incompetence includes to tendency to overlook your own incompetence.
That video is very disturbing. The way I see it, those fines the banks regularly pay are a shakedown tax. They pay it with a wink and a nudge, and they are allowed to stay in business, overcharging the hoi polloi.
It’s just a share the loot scheme. If the gov’t was serious, some bank officers would be in the penitentiary, and some banks would be put out of business. But that never happens, does it?
indefatigablefrog
That was an LOL moment. Generally, you can’t really fault a non-scientific “civilian” for not spontaneously recognizing a number like that.
However, she’s a news reporter presenting a prepared story that plainly contained a critical number she hadn’t thought about. Reporters (perhaps not this lady) do this all the time with “global warming” or what ever we’re calling it this week.
Beauty is skin deep, but stupid goes clean thru…
“If the gov’t was serious, some bank officers would be in the penitentiary, and some banks would be put out of business. But that never happens, does it?”
It does in Iceland.
I can fault them.
I could have read that number when I was seven years old.
These are ninnies, and we are living in the dumbification of civilization…truly an idiocracy.
This is two years old and has nothing to do with the current discovery in this post. Having said that, it is still the most stupid question of all time.
Those youngsters are understandably confused. To us, a billion was always a million million, but then the Americans started using the term for a thousandth that value, being lovers of hyperbole…. (grin)
In other words he doesn’t know!
Well CO2 gets charged with electro-solar energy and then acts like a magnet, since meteorites have metal in them, the electrically charged CO2 attracts the meteorites to earth. Just look at the facts; 26 multi kiloton impacts since 2001 alone. Yes there is no misery or evil CO2 is not capable of. Would not be surprised if CO2 attracted flesh eating alien zombies as well. (That there is so many zombie movies is no accident)
“hat there is so many zombie movies is no accident” indeed.
Note that flesh is largely composed of carbon too, and zombies can’t get enough of it!
I’m prepared to believe that global warming is responsible for Bill Nye’s increasingly unscientific bent. Hyperthermia is known to cause all kinds of mental aberrations… There is however, no rational explanation for CNN.
“more than large enough to devastate an entire city”
At that speed and size it would devastate more the a large city in my option. If it hit say a deep area in one of earths oceans,the waves that would be created would be up to about a mile high and thousands of feet high when hit shore lines.
Would not be a good day.
Now you’re talking sea rise!
Complete agreement. Asteroids should be the top priority of NASA – way ahead of any Mars trolling or any other function.
“way ahead of any Mars trolling or any other function”
or
global warming
or
muslim outreach
or
sks blog.
This is not a near miss….. It is a near hit. that might focus minds a little more.
Quite agree !
A near miss would mean to nearly miss (something) whereas, a “near hit” …….
Polite Note to Eric re “impact events”.
… so; should we say, “in the event of an impact event” ?
An impact is an impact. An event is an event.
To say “impact event” suggests some sort of tournament like jousting.
Here in Britain, we watched a Met. Office TV weatherman (a few years ago) as he warned us of an impending “snow event” ! His snow event warning was laughed all the way to the “front pages” and never heard again.
Regards,
WL
That would be a matter of semantics–see how easy it is to create fear with a little word spinning?
Is this a discussion about what the word”is” is?
I have seen a similar discussion on this usage elsewhere. It hinges, I believe, on the expanded meaning of the word “near”. If you truly mean “nearly”, then you are correct for “nearly miss(ed)” would be an actual hit. If you actually mean “nearby” as in “Dang! That was close!” then the usual understanding would be correct.
You have it wrong.
This is a (adjective) miss. That is not the same as saying that it (adverbially) missed.
So ” a near miss ” is correct; but ” it nearly missed is incorrect.
g
It will be a close shave, but we will not be shaven closely,
No. “Miss” in this case is a noun, and it is modified by the adjective “near”.
I’d rather have a near Miss than a far Miss.
And a warm one rather than cold too
With enough warning people could be evacuated from likely impact zones.
Or at very least they could stick their fingers in their ears, stick their head between their knees and kiss their ar*e goodbye.
The missing letter (*) is probably “s” which would spell “arse”.
Regards,
WL
To paraphrase Bill Clinton, “depends on the meaning of enough.”
Not to mention their asteroid.
Nasty. But you can buy a creme for that…
Just play dubstep at top volume on a 2400watt sound system, and the apocalypse, when it came, would pass you by, unnoticed.
Your lucky neighbours would also be unaware that they had escaped annihilation.
Although they may at that point be wishing for a merciful release from the torment.
2015 TB145’s orbital inclination and speed suggests it is of cometary origin. Comets travel faster than meteors and asteroids since their orbit extends far beyond the planets in the solar system.
Because comets are faster (and sometimes much, much bigger) than asteroids, they have more destructive impact potential. The Earth has probably not been hit by a large comet in the last 3.8 billion years.
Running the numbers on this body indicate if it hit land at a 90 degree angle, it would create a crater with a diameter of 5 kms, about 4 times larger than Meteor Crater in Arizona.
Um, only 1.3 lunar distances is not very far, it is well within our gravitational influence, is it not?
The path is calculated taking Earth/Moon gravity into account. Planets don’t just reach out and grab things as they go by.
Gravitational influence extends to infinity.
g
I was going to say the same thing…the whole universe is within the gravitational influence of my cat.
And I am talking about the smaller one!
Which would be just the right size to obliterate Washington, DC. (Hey, we can dream!)
“just the right size to obliterate Washington, DC.”
Let’s hope that’s not the case, it’s not just politicians live near DC.
Unfortunately only the politicians would have the means to get out of town in time.
Um, that means the politicians wouldn’t have anybody left working for them. And, that means they just might have to work themselves at an honest endeavor.
Maybe not so unfortunate after all. Think of a politician forced to live in the world we do. Cool.
There is no good place for it to hit, but Washington would be among the top twenty.
Just to be certain: you meant Washington DC, right?
A lot of bureaucrats also live near DC.
See the largest 10 impact craters.
See list of impact craters
There will be a huge astroid hitting the ocean in the future.!
…a rock cut out of a mountain without human hands…
Daniel 2:45
Correct me if I’m mistaken, but don’t they always (eventually) come in at a 90 degree angle ?
You don’t see many craters that look like a ricochet.
Or is it just me ?
I know that it’s counterintuitive, but no matter the angle of impact you get a circular crater.
See Niven and Pournell’s “Lucifer’s Hammer”
Cheers!
Actually, very few hit at 90 degrees. Planetary geometry & motion makes objects much more likely to come in at an angle.
I think it’s the explosive impact that creates the crater. The crater’s much bigger than the asteroid; a little like a bomb going off – a really big bomb. The temperature at impact sites is high enough to form glass-like rocks.
Those are just my assumptions though.
I think that meteor crater in Arizona is an example of this and Barringer himself did experiments with bullet rounds showing the effect on a small scale:
http://adsabs.harvard.edu/abs/1995Metic..30Q.567R
http://www.encyclopedia.com/doc/1G2-3437800059.html
http://www.scientificamerican.com/article/why-are-impact-craters-al/
Actually, they never come in at a 90 degree angle.
g
You can get elliptical craters, but the angle has to be quite shallow. And they often produce ‘butterfly craters’. I think the problem with the NASA hypervelocity gun is that it cannot reproduce shallow angles, so not so much research has been done regards this type.
A butterfly on Mars.
http://cintos.org/ge/Portraits/mars_butterflyTrim_web.jpg
“Correct me if I’m mistaken, but don’t they always (eventually) come in at a 90 degree angle ?”
Try throwing a stone into water at a shallow angle.
The splash always goes vertically upwards.
catweazle666
October 24, 2015 at 7:36 am
u.k.(us)
October 23, 2015 at 7:46 am
“Correct me if I’m mistaken, but don’t they always (eventually) come in at a 90 degree angle ?”
catweazle666
October 24, 2015 at 7:36 am
Try throwing a stone into water at a shallow angle.
The splash always goes vertically upwards.
Better yet, try shooting soft pellets into your favorite small tub of water with a camera mounted nearby to record the entry and splashes. A small container is better because you can note also the wet spots on the floor as temporary record of where the splashes go, in addition to the video record.
Most of us will not have access to high-speed recording equipment, but your standard 24 or 30 fps digital camera will record enough information to verify what catweazle666 says, but there is more.
No matter the angle of approach, projectiles hitting water always produce a vertical water column, or spike. In addition, my seat of the pants experiments described in the preceding paragraph also revealed that for low angle shots at least, there are also splashes fore and aft of the point of impact, but the ripples are always concentric circles radiating outward from the impact point no matter the approach angle of the impacting body.
With asteroid or other rocky body impacting a planetary body, there is a great deal of heat generated at the instant of impact, which force melts the surrounding regolith so that it temporarily acts as a fluid long enough for a concentric ripple to form, and also sometimes a central spike, before the formation cools rapidly, and leaves its record not only for posterity, but also for curious astronomers.
And if it hit oceanic crust, it would pierce the Mantle …
The effects of comet impact would also depend on its composition. I gather that some are made up of mostly ice and some are also composed of many smaller fragments. Luck o’ the draw… Does anyone know if they (“the Authorities”) have the ability to measure density of these things?
To my pisspoor understanding, gravitational influence is believed to spread out through the universe at the speed of light.
Therefore, it does not extend to infinity.
BUT, the gravitational influence of the earth does reach out far into the cosmos already.
https://en.wikipedia.org/wiki/Speed_of_gravity
Apologies, the above comment was not intended for this location on the thread.
The concept of infinity is invented by man , not nature . There is utterly no proof that the universe is infinite and that is where our understanding of “space” breaks down , what is the alternative to an infinite universe or more accurately infinite room for the universe to expand into ? Such thoughts quickly end up in the realm of Philosophy and specifically Metaphysics.
ddggrraahhaamm,
But, but… there’s no proof that the universe is finite, either.
I agree with you about metaphysics, etc. But sometimes it’s fun to speculate.
What I wonder is, why is the speed of light so very slow?
Misplaced comment was interesting. I think you won the nit-picking contest.
@ur momisugly dbstealey.
What is your bandwidth ?
DC to Gamma.
The Earth has probably not been hit by a large comet in the last 3.8 billion years.
The comet does not have to hit earth to cause immense damage. That type of an event has probably happened many times considering earth’s age. The passing of 1680 comet was fortunately far enough away not to cause major damage .
In your opinion, what can an object that passes close to the earth do to it?
If you are talking about comet gasses, they are way to thin to hurt anyone. Heck, I doubt they could even be measured.
MARK W
In your opinion, what can an object that passes close to the earth do to it?
Remember I was talking about a large comet , the size of the one in 1680. If this came close enough to earth’s orbit, it could cause devastating damage like huge storms, sudden weather changes , volcanic eruptions , earth quakes , immense floods, tsunamis and even pole shifts . The impact of the charged tail alone would be devastating. I believe this could have happened before .
The great 1680 comet
http://www.jwwerner.com/history/Comet.html
From http://echo.jpl.nasa.gov/asteroids/2009FD/2009FD_planning.html, this guy, 2015 TB145, goes on quite a ride between perihelion 0.295 au (inside the orbital distance of Mercury) and aphelion 3.9 au (between asteroid belt and Jupiter).
If the asteroid is at the upper range of the estimate – 640 meters in diameter – and assuming a spherical geometry, and an average density of .002 kg/cc, then the kinetic energy = 1/2 mv^2:
m = 4/3*pi*(320 m)^3 * 10^6 cc/m^3 * 0.002 kg/cc = 2.745*10^11 kg
v = 35000 m/s
ke = 1/2 * 2.745*10^11 kg * (35000 m/s)^2 = 1.68 * 10^20 kg m^2/s^2 = 1.68 * 10^20 joules
A gigaton nuclear weapon would be 4.184×10^18 joules, so the kinetic energy, most of which would be expressed on impact, would be around 40 gigatons, or around 40,000 megatons, if my calculations are right.
I think you are right – it is based on the energy released for high explosive being set at 1000 calories per gram.
Would you happen to know what the energy released by a large volcanic explosion is – Vesuvius, St Helens, Krakatoa, Mt Toba?
I’ve updated the calculations, below …, taking the estimated (not worst case) size of the thing, and so forth. Somewhat lower ‘yield’ of course, but still … something really big. We simply do NOT want these kind of things impacting the planet, if we can help it. Oh … its not an “extinction event” sized object, or even a “civilization squashing” object. But it’d very likely “change the climate” for a few years. If (as is statistically most likely), it were to ‘impact’ one of the oceans, it might make quite the basin tsunami. Or not: I don’t have access to the nonlinear finite element plasma analysis that Lawrence Berkeley Labs has. GoatGuy
Goatee,
My query is how many have there been in – say – the last 1,000 or 10,000 years.
Certainly – absolutely certainly – our planet will get one – or more; perhaps two like it in twenty or fifty years.
But – how long is it – sort-of-half-likely – to be . . . . . .
By all means study.
Let us also study defences.
But the last – historic, archaeologic, recent palaentologic – years show little to match the Barringer Crater.
Right – that sort of missile in the middle of any City will make dramatic changes in the cityscape – for sure, and likely cool the planet [dust] for some years.
Even one a hundredth the size – sort of tennis court across at zzzip-speed.
But we don’t get one every year.
And there is a lot of wilderness into which they can fall.
Even in the UK – land area – and enclosed lakes, like Loch Ness or Rutland Water – much area is pretty empty.
NOT NO VICTIM – BUT ONLY A FEW – SEROUSLY UNFORTUNATE souls.
Cities won’t get hit too often.
Maybe a megacity is already line up – but that is not the way to bet in a century!
Auto
Not to worry! By Ethan Siegel’s expert assessment in Forbes Magazine, says “Defending us from asteroids, from a reasonable cost-benefit analysis, simply isn’t worth the investment, statistically.” His essay was well presented — and aside from a bit of confusion about so-called ‘city killers’ and how often they are projected to arrive — it is a point of view that could be understood by any insurance underwriter.
Why is then that my first though after reading the article was… Mr. Siegel… may you and the cost-benefit analysis you rode in on, go straight to HELL.
When you learn you are facing an existential risk, isn’t it the moral responsibility of every parent to acknowledge that risk and take forward steps, whether large or small, towards the mitigation of that risk?
Isn’t applying risk assessment to existential risks a bit like dividing by zero?
Best response to a bad cost- benefit question. And it’s really funny! (foul language alert).
Ok – THAT WAS FUNNY!
Where is Buck Rodgers when you need him ?
I have always been curious about these types of events.
If such an object crashed into the moon, could it push the moon out of orbit and a decaying orbit with earth?
Now that would make for an interesting sci-fi movie. the world watching the moon begin to accelerate into the Earth’s atmosphere. Presumably it is possible the decay could be relatively slow, occurring over a number of years until it collides with us, with catastrophic consequences
Knocking the Moon “out of orbit” with a comet or asteroid would be like knocking down the Statue of Liberty with a BB gun.. Way too much mass and too stable an orbit to even cause a blip.
Planetary orbits are not fragile.
Orbits are neither stable nor unstable, they just are. It’s not like the moon has worn a track in it’s current orbit that it has to be knocked out of.
The only thing that matters is how much the moon’s speed and direction are changed by an impact. Or the gravitational tug of a passing mass.
As you point out, the energy of any potential impactor is to small to change the moon’s orbit by more than a few feet, and the mass is so small that even a miss by only a few feet wouldn’t change the orbit by enough to be measured by even the most sensitive of instruments.
“We don’t really know”
Regards,
WL
But we can predict what the Earth’s climate will be in 50-100 years./sarc
The only way to get a decaying orbit, would be to have the moon orbiting close enough to the earth that it was being impacted by the earth’s atmosphere. IE, the inner edge would have to be about 100 miles from the earth’s surface.
Which is a physical impossibility.
Roche limit for Earth/Moon is about 18,000 kilometers. The Moon (and some of the Earth) would be pulled apart due to gravitational tidal forces at that distance.
Actually the Moon is thought to have been put into the sky by a collision of a small planetary body against the Earth. Obviously the consequences of such an impact are incompatible with life on Earth. Some scientists believe that the origin of the Moon had a lot to do with the development of the oceans and the atmosphere of the Earth, as many of the elements were trapped in the mantle and were released by the explosion.
The moon is also slowly moving away from the Earth (I don’t know the rate off-hand, but I believe it’s about an inch per year).
That must be the extra pressure from the surplus CO2. Cosmic pollution!
Neal Stephenson’s new book (fiction) deals with the destruction of the moon. It wouldn’t be pretty.
Why would it be a decaying orbit; presuming of course that it never gets close enough to encounter any of earth’s atmosphere. Shall we say closest approach is 10,000 km.
With the moon coming that close to earth at perigee, the tidal forces would be much greater than they are now, so the rate of transfer of angular momentum, from the earth to the moon would increase, and the moon would be drifting away from earth, like it is now, rather than slowly falling in.
So if an object dislodged the moon into a 10,000 km perigee orbit, so it was a clean miss on the first pass, then it would never ever hit, unless dislodged again.
g
Or, rather, that the the probability of impact is very low, even though possible consequences are catastrophic.
Which is when the catastrophists and green-shirts wheel out the precautionary principle, and say “we must do something, just in case”. The religious might pray, which in a minimal form does at least have the merit of letting others get on with their own lives. The prayers can pray, and the rest get an unchanged tax rate.
Having said that, I don’t think asteroid-impacters should be given a ride any easier than the global-warmers in their quest for publicity and funding.
Asteroids can wipe out all life on the planet, or at a minimum really ruin your day. The proof is in the planet’s surface. To compare this to CO2 is ridiculous. You may not care if humanity goes the way of the dinosaurs, but I do.
Let’s be clear about something. Humanity will go the way of the dinosaurs eventually. There are myriad possibilities, but the net sum outcome remains zero chance of infinite survival.
The data says that really large asteroid impacts only happen once every 67 million years. (and counting)
that doesn’t rate as a very big worry to me. These “near misses” have always been happening, they just seem scary because for the first time we actually know about them, thanks to technology.
You don’t need a really big one to cause problems. Meteor crater in AZ is only about 50K years old, if it had hit a modern city instead of the an uninhabited city, the death toll would have been in the millions.
The meteor from last year was only about 50 feet across, but it managed to injure hundreds, even though it didn’t even make it to the surface.
How about Tunguska, only 107 years ago. It had enough energy to pretty much level a city. Lucky it exploded in remote Siberia.
Read somewhere that the flash from the Arizona impact would have blinded people all the way to Denver. That may or may not be true but you’d not want to be anywhere near when one hit. Various coastal areas around the world including the southern US and Western Australia have large boulders hundreds of miles inland – the result of tsunamis from impacts.
The Meteor Crater impactor was moving at the same sort of speed as this one: 35,000 MPH.
Hmm, is that counting the possibility of the Younger Dryas being caused by an impact event, or excluding it? The YD was only 12,900 years ago – a blink of a geological eye.
Ralph
“The data says that really large asteroid impacts only happen once every 67 million years.” But it’s like “your chances of falling under a bus are once in every 20o years.” That doesn’t help those who fall under a bus tomorrow. So that really large asteroid impact could be next year – plausible that telescopes have not yet spotted it.
Dudley
massive glaciation happens a lot more often than 65 million years too. Shouldn’t we be getting ready for that also, since another ice-age would destroy our civilisation?
“massive glaciation happens a lot more often than 65 million years too.”
But it doesn’t approach at 35,000 MPH.
Unlike catastrophic global warming, apparently…
“Chelyabinsk received no warning when it was struck by a meteor. ” It might be better to state that, “Chelyabinsk received no warning when it was struck by an “exploding meteor’s blast wave”.” Yeah, quibbling but a little more accurate.
What’s interesting is the continuing discovery of objects that have orbits of high inclinations to the plane of the eliptic, i.e. the nominal plane where the planets orbit the Sun. You’d think that most of the comets and asteroids would have orbits closer to the eliptic plane as left over pieces from the formation of the solar system but, of course, that would be too easy. The Oort cloud extents out about half way to the nearest star so any object out there who’s orbit’s preturbed and ends up heading toward the Sun can come from any direction imajinable. Eye’s wide open and looking everywhere is the only answer.
Not that we could do much of anything about it when something big (100m+) comes at us at 20km/sec+ but try to get the heck out of the impact zone. Yeah, even if the impact was in or over (object explodes prior to ground impact) an ocean the effects may be catastrophic because of the tsunamis created. “Ok, what do we do with the population of LA and it’s surrounding cities?”
Am I going to worry about it? Nope. I can’t do anything about it so no sleep lost. Interesting to think about? You bet.
” orbit’s preturbed ”
Is that better or worse than being postturbed? 😉
Good to see you are still on the job.
Apparently there is one about the same size heading towards Earth which has a 1 in 63,000 chance of hitting us in 2032. They calculate an impact force of perhaps 2,500 megatons. I guess my question is; how is it that one potential asteroid strike can be discovered 17 years in advance, while another of similar size can be missed until weeks beforehand?
http://www.belfasttelegraph.co.uk/news/world-news/massive-asteroid-that-could-hit-earth-in-2032-with-force-50-times-greater-than-biggest-nuclear-bomb-29672038.html
The one in 2032 was spotted during a previous orbit when it came close to the earth. I’m guessing that on previous orbits, when the current one passed the earth’s orbit, it was on the other side of the sun, or far enough away that it was missed.
According to THGTTG: “Space” it says, “is big…”
Let’s see an honest photo of how close the grand seed vault in Norway is to the beach.
That’s why we need to keep several Orion class spaceships in reserve.
However, the concept has to be implemented &. tested first ASAP. If it looked feasible 47 years ago, in 1958, it’s certainly only a matter of funding &. will to do it today.
It is getting urgent. The fact there was no planet buster collision in our past tells us nothing about its probability. Unconditional probability of our survival to this very date may be arbitrarily small, because we only know a conditional probability, that is, the probability of survival provided we do contemplate the issue. That’s exactly one, but this number is utterly uninformative about the future.
57 years
Ah… not so sure. Orion class space venturing is only thought to work. A lot remains to be done to make it actually so. This is not to say that I don’t also think we should be researching it!, just that it may turn out to have some really stupid ‘insolvable’ problems.
At this point, PANSTARRS has figured out that of the 50% or so objects that it can detect mostly near the plane of the ecliptic, there are NEOs (near earth objects) or ECOs (Earth crossing objects) that are in the Earth/Moon distance at a rate of 1 every few years. Maybe more often, as we likely miss most of them (like this article’s object) that are coming in at a higher angle from the ecliptic. 1 a year.
Thing is, to impact Earth, its a statistical problem. The circular bull’s eye target represented by the Earth-Moon system is 400,000 km in radius, or 500 billion km² in area. That’s the whole target, not the bull’s eye. The Earth (bull’s eye) is only 6,700 km in radius, or 141 million km² (0.414 billion km²) in area. So, statistically there is a 1 in 3,500 chance that one of those ‘once a year’ close flybys will actually impact good ol’ Urth.
Wikipedia’s Earth Impact page ( https://en.wikipedia.org/wiki/Impact_event ) seems to think that objects the size of this article’s focus impact the earth about every 79,000 years. I think rather not: Objects this size undoubtedly cross the Earth-Moon dartboard every few years, and with 1:3,500 chance of hitting Earth, that’s maybe 10,000 years between events.
Do take a trip to the Wikipedia page: there’s an excellent map of the worldwide distribution of impacts and airbursts from 1994 to 2013. A map! Worthy.
GoatGuy
We just need a B Ark for all the climate “scientists”.
Hey don’t worry, all that surplus carbon in the atmosphere will abrade it and keep us safe 🙂
Working in IT infrastructure, sometimes managers who were never engineers ask silly questions before a core network change. Once, we were asked the question, which was essentially, “please list all the unknown issues you could have.” So… I went to Spaceweather.com, scrolled to the bottom of the page, used ScreenPresso to capture the Recent/Upcoming Potential Hazard list. I put that in the email and noted that NASA could be wrong and we could lose access to both data centers (one of those flying rocks was doing a flyby that day.) 😀
Rather than Ursa Major, they should be training their telescopes just to the right of Orion’s Belt for companions trailing behind in the same orbit. Along with Frank Davis, I’ve tentatively linked three large meteors to known passing asteroids (same cosmic radiant; same cosmic speed before gravity well acceleration within 5-10% error). If linked, then the 5-10% error is due to to trajectory characterisation errors by Earth based meteor observers, not by the orbital simulation programme that is exquisitely accurate.
Cosmic radiant for this one, 2015TB145, is around 4H 12min RA; -2° 07 min Declination. That’s not dead on (taken from JPL horizons @ur momisugly 2 weeks out) but close enough for checking for rocks 2-5 days out and bearing down on us.
Space agencies should be scanning all the way along the orbit line for companions as well, not just the ‘tunnel’ that the Earth makes through the rock train. This is the best opportunity in a decade to check for trailing rocks (large asteroid, close Earth MOID, close pass, high speed means associated meteors are difficult to mistake for anything else).
The tunnel entrance is at the radiant given above. If we can firm it up a bit more accurate, I’ll post it up but we have other projects going.
Meanwhile, here’s a link with more info (see comments including diagrams from Frank):
https://tallbloke.wordpress.com/2015/10/19/surprise-asteroid-to-give-earth-a-halloween-flyby/
“Even very large threats could potentially be addressed, if there was enough time to prepare.”
That depends on the location of the impact.
If it is on land, apart from the local impact damage and seismic effects, a very large quantity of dust will be injected into the atmosphere which will cause a severe cooling effect. It is probable that will not exterminate all of humanity and the higher animals.
If it lands in the ocean, the majority of its kinetic energy will be transformed into superheated steam. The effect of that will be apocalyptic.
Maybe the ocean will be so acidic by then that it will simply dissolve it.
sarc
As Phil sez…
(1) Its likely cometary in nature: not exactly a fluffy snowball, but certainly low density … and would be destined to deflagrate on atmospheric entry unlike a metal-type or even a chondritic meteoroid. So, it would be more like an atomic bomb that a crater-digging meteor impact.
(2) The likely diameter is based on its albedo, which is a chicken-and-egg problem: Until one can measure the actual diameter, the albedo can’t accurately be known. However, other similar bodies have been measured, so “guessing albedo around 0.33” isn’t bad. This leads to a diameter of 320 km, within a factor of 2.
(3) The density of the thing, if cometary, would be low. Less than 2 Mg/m³ (metric tons per cubic meter). Could be as low as 0.3, but for a small object, that’d be rare. Call it 1 Mg/m³ ≡ 1000 kg/m³.
PHIL made a little mistake in his calculations, but essentially
r = ½d (radius is ½ diameter)
V = ⁴/₃ π r³ (volume is related to radius cubed in his formula, not diameter!)
M = ρV (mass is volume times density)
E = ½Mv² (energy is related to square of velocity)
1 kt = 4.12×10¹² joules
Push ’em all together, and you get
r = ½ 320
r = 160 m
V = ⁴/₃ π r³
V = ⁴/₃ π 160³
V = 17,100,000 m³
M = ρV
M = 1000 V
M = 17,100,000,000 kg
E = ½ Mv²
E = ½ 17.1×10⁹ · 35,000²
E = 1.05×10¹⁶ J (joules)
E(kt) = 1.05×10¹⁶ ÷ 4.12×10¹²
E(kt) = 2,550,000 kt
E(Mt) = 2,550 megatons
So … lets just say, that this sonuvabitch would be more than a little “city buster”. This would be something unleashing the entire power of the nuclear arsenal of China, France, Britain, India, Pakistan combined. Or about 25% of the estimate of all nuclear weapons that might be deployed in an ‘all out’ nuclear war.
Nuclear Winter?
Nah… not really. Most of the heat and explosive yield would dissipate relatively quickly, the meteor being a point-impact situation. But … to put it in perspective, at an atmospheric ‘detonation’ (complete deflagration to plasma, heat, explosive yield) of 50 km (Chelyabinsk) to ground level (Lawrence Berkeley sims), the “5 psi” ring would have a diameter of 200 km, or an area (πr²) of 30,000 km². this is about 300 times the area of the greater Parisian metropolitan area.
City buster? Mmmm… region buster. This thing would make good ol’ Tunguska (Siberia 1908, 15 MT) look like a firecracker by comparison.
(Thanks Phil, for the calculations)
GoatGuy
“This leads to a diameter of 320 km, within a factor of 2. ”
Shouldn’t that be meters? “…indicates that its diameter is probably within a factor of two of 320 meters“
yes. Writing takes second place to calculating, I’m afraid. And this site doesn’t seem to let one EDIT the comment once posted. Glad you found that. The calculations tho’ remain correct.
Of course you do realise that ‘ 25% of the estimate of all nuclear weapons that might be deployed in an ‘all out’ nuclear war. ‘ have long been held to be more than enough to wipe the planet clean several times over?
Well that was what the Soviet sponsored CND said, anyway.
Not really, Leo. (wipe planet clean, several times). We tend to forget or underestimate (we the common bloke, or ordinary hyped up reporter looking to make an attractive splash), just how BIG the earth is, and the scale(s) of energy required to significantly damage the ecosphere.
For instance … 2,500 megaton to 10,000 megaton impactors hit the planet randomly and fairly frequently … anywhere from 5,000 years to 50,000 years [i]on the average[/i]. These are definitely [i]“nuclear arsenal sized impactors”[/i], yet … somewhat contrary to your [i]“wipe the planet out”[/i] scenario, they haven’t. Haven’t and can’t. Oh, they can make for a bad situation, for starvations and famines; they can trigger [i]“impact Winter”[/i] seasons, for at least a year, if not a decade.
But this doesn’t [i]“wipe the planet clean”[/i] at all. True impact … not much different than if the [i]Gulf Stream[/i] were to cease for a decade or three. Which seems to happen with depressingly frequent periodicity.
2,500 to 10,000 megaton of [i]“where the Hêll did that come from?”[/i] impactors [u]over land[/u] and especially [u]over highly populated areas[/u] (such as greater Europe), would be terrible, terrible events. Millions would die immediately, if anywhere near one of the Great Cities. But again, if we just [i]“do the statistics”[/i], the Great Cities make up less than 0.2% of the planet’s [i]entire[/i] surface. The [i]“asteroid winter”[/i] effect would be larger, but not likely to be global. Hemispheric? Sure. Truth is, even a big (not ‘giant’ as in Chixulub) relatively common-place event would have a 78% chance of hitting an ocean, a 21.8% chance of hitting a low-or-uninhabited corner of land, and a 1 in 500 chance of hitting a city.
So, 1-in–500 times 1-in–10,000 years = 1 in 5 million chance [i]on any year[/i] of getting a big city hit with a big impactor. Worldwide. Chance of [b]your[/b] big city getting hit? Oh… one in a billion or so (there being 200 large cities, worldwide, say).
I’ll be sleeping soundly tonight.
And tomorrow.
And the rest of my life.
[b]Goat[/b]Guy
“and would be destined to deflagrate on atmospheric entry unlike a metal-type or even a chondritic meteoroid. So, it would be more like an atomic bomb that a crater-digging meteor impact.”
With regrets, no. Depends on what you think the depth of the atmosphere is, assume 70 km. So if it falls vertically it is 2 seconds from entry to impact. Not enough time to deflagrate or disintegrate. Coming in at a shallow angle, say it has 20 s between impact and entry, not enough time to do more than burn off the outermost 2 or 3 metres. Probably worst case would be a near horizontal entry – the famous skip and bounce entry originally favoured for returning astronauts before the heat-shield was developed – a white hot object like the Chelyabinsk object but rather larger and with a much longer trail of devastation.
Someone considered a large asteroid knocking the moon out of orbit, which possibility was rightly debunked. But what about the possibility of the 1.3 earth-moon distance being a slight exaggeration, so it is not 1.3 but 1.03, and the asteroid skims the moon’s surface. How close would it have to be for the moon to alter the direction of travel by 90 degrees, and straight into earth? At a mean distance of 384 400 km and 35 km/s, this gives a tad over three hours to impact!