NASA: Previously Unknown Asteroid had a Near Miss with Earth today

We dodged a bullet today. It came within one half of the distance to the moon.

I got this notice in email from NASA about a surprise asteroid that gave us only one day of warning passing halfway between the Earth and the moon.  It was the largest known asteroid to ever pass that close to Earth in observational history.


SURPRISE ASTEROID FLYBY: With little warning, on Sunday, April 15th, a “Tunguska-class” asteroid about the size of a football field flew through the Earth-Moon system. 2018 GE3 was discovered just the day before as it plunged inward from the asteroid belt. A quick-thinking amateur astronomer in Europe was able to record a video of the asteroid as it flew by.

With little warning, a relatively large asteroid flew through the Earth-Moon system on April 15th only 192,200 km (0.5 Lunar Distance) from our planet. 2018 GE3 was discovered by the Catalina Sky Survey approaching Earth on April 14th. Hours later, amateur astronomer Michael Jäger of Weißenkirchen Austria video-recorded the space rock rushing through the southern constellation Serpens:

2018 GE3 an asteroid from the inner regions of the asteroid belt, classified as a near-Earth object, approximately 37–138 meters (100–500 feet) in diameter. It was first observed on 14 April 2018, only one day prior to its sub-lunar close encounter with Earth at 0.50 LD (0.00128 AU) on 15 April 2018. It is the largest known asteroid to ever pass that close to Earth in observational history. Animation by Michael Jäger

“According to Wikipedia, 2018 GE3 is the largest known asteroid to pass that close to Earth in observational history,” says Jäger. “It was shining like a 13th magnitude star at the time of my observations.”

Based on the intensity of its reflected sunlight, 2018 GE3 must be 48 to 110 meters wide, according to NASA-JPL.

This puts it into the same class as the 60-meter Tunguska impactor that leveled a forest in Siberia in 1908. A more recent point of comparison is the Chelyabinsk meteor–a ~20-meter asteroid that exploded in the atmosphere over Russia on Feb. 15, 2013, shattering windows and toppling onlookers as a fireball brighter than the sun blossomed in the blue morning Ural sky. 2018 GE3 could be 5 to 6 times wider than that object.

If 2018 GE3 had hit Earth, it would have caused regional, not global, damage, and might have disintegrated in the atmosphere before reaching the ground. Nevertheless, it is a significant asteroid, illustrating how even large space rocks can still take us by surprise. 2018 GE3 was found less than a day before before its closest approach. 

Based on an observational arc of only 1 day, 2018 GE3 appears to follow an elliptical orbit which stretches from the asteroid belt to deep inside the inner solar system. Every ~2.5 years the space rock crosses the orbits of Mercury, Venus, Earth, and Mars–although not necessarily making close approaches to the planets themselves.

NASA Jet Propulsion Laboratory has made an interactive orbit viewer available online here

Via NASA Spaceweather

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185 thoughts on “NASA: Previously Unknown Asteroid had a Near Miss with Earth today

  1. I thought that NASA was supposed to look out for these things. If they spent less time toying with CAGW Global Warming and assisting in the fabrication of Climate Data, they might be doing a better job.

    • Yeah, NASA really needs to get its priorities straight and move asteriod detection/mitigation high up on their list.

      • Clearly the Russians were shielding this asteroid’s movements and thus put innocent lives at risk.
        It is also ‘highly likely’ that there were chemical precursors like chlorine on board making Russia ‘ultimately responsible’ once again !
        When will Pootun be held to account for his irresponsible actions?

      • Greg, I’m sure your attempts to make Putin and Russia look better are appreciated. Somewhere.

      • It should go to No.1 on the WORLD’S list — a hit by even a small one would probably destroy us and the world.

    • Dark asteroids are nearly impossible to detect until they get close, and then its either not an issue or its too damn late. Spending is not the issue unless you want to spend a lot more. There are innumerable (probably unknowable) number of earth crossers, as we don’t know about them until we find them and document them. If coming from out of the ecliptic, they are difficult to see and may have higher periodicity but we may never see them if their crossing point is not witnessed due to alignments.
      These aren’t comets. They don’t spew glistening tails. If you aren’t watching that part of the sky you won’t see it moving.
      What exactly do you expect for earth defense?

      • When a large enough one hits and it is a question of when not if; the earth will be plunged into a dust like nuclear winter and global warming will hit the dustbin of history. Of course we have to make it hit the dustbin of history right now or we will all be bankrupt.

      • “What exactly do you expect for earth defense?”
        NASA needs to find all the asteriods that can hit the Earth, and they need to step up the development of methods to move asteriods, such as using lasers.
        NASA has a test coming up in about 2020 where they plan on crashing a projectile into an asteriod to evaluate this method of asteriod movement, but besides this project NASA has nothing else. They need to get space-based lasers in orbit powered by Solar Power Satellites as another method of moving asteriods, but that doesn’t seem to be on the radar for NASA right now.
        I think NASA should make this a priority higher than sending a human to Mars. Not that we can’t do both, but Earth protection should take priority if we have to choose, imo.

      • Re: “What exactly do you expect for earth defense?”
        Pulse radar with multiple receiving stations to triangulate objects location in space. Arthur C Clark covered this decades ago.

      • I want to spend a lot more on this. Redirect all the money we currently waste on worrying about, or ‘mitigating’ what the Carbon Death Cult tell us.

      • earth defense?
        Maybe Radar? High RF output Geosynchronous Doppler Radar satellites that all transmit & listen in-sync up around 20 Ghz? (Wide beam helix antennas) Any object coming in (or going away) with a radar/cross section (not a perfect sphere) is going to bounce back some Dopplering signal.. A signal that could be heard by the satellites, and maybe even ground stations. Unless the rock is too small for the amount of xmit signal..
        Of course, a really good system isn’t going to be cheap.. And, we would need strict emission control on that band.. Yes, the system could be hacked using simple hardware.. 🙁
        This kind of system could be placed in orbit over a period of years.. So the cost isn’t going to be all at once. And it would not have full coverage all at once..

      • Sorry to rain on your fantasies.
        Interesting ideas all and perhaps eventually possible, but not in our lifetimes and certainly not for the paltry sums you mention.
        I am well aware of the current capabilities of high powered lasers. They can disable drones and burn a hole into an outboard motor at some range, but deflect and asteroid….not just there yet. And space-based….not even close.
        Where would all these look-out posts be located, and how will they be manned? powered? provisioned? maintained?
        Again, we don’t have sentinel outposts stationed about the heavens looking into the dark for asteroids. The money you would transfer into this budget would be accepted graciously, but it would not even come close to paying for what you dream about.
        Arthur C. Clark was a visionary who foresaw the advent of communication satellites, but he didn’t invent them nor build them. Science fiction is entertaining, rocket science is hard, but rocket engineering is much, much harder. Any college freshmen could calculate an orbital trajectory, but how to make a machine that will perform as desired, reliably and safely…..well that’s my job. Star wars is entertaining, but far from reality.

      • I’ve wondered about the possibility of using space based lasers to help with the problem of space debris.
        Capturing the big stuff isn’t that big a problem, and there’s not that much of it.
        It’s the small stuff, a few inches in diameter and smaller. Lots of it, and it’s not efficient to send satellites after it.
        If we could use a laser to slow down these objects so that they drop into a lower orbit, then let the thicker atmosphere down there take care of the rest.
        The problem of course is designing a space based laser as well as systems for the detection and targeting of the debris.

    • I recall reading many years ago that NASA had recommended a budget over the next 10(?) years to search for and catalog asteroids over size “X” but then the budget was cut to 1/3 to catalog asteroids double or more size “X” in favor of studying the horrible threat of global warming.

    • NASA definitely has a program to identify these kind of intrepid visitors. Thing is, as every announcement from NASA reminds, it is a statistical discovery program; it simply cannot (ever) know with absolute certainty the ephemera of all the NEO asteroids. If for no other reason … than occasionally individual NEOs (and non-NEOs!) orbits change thru so-called 3-body perturbations.
      The other side of the detection coin is best stated as “detection of what?”… because detection is all about 4 things:
      [1] opportunity
      [2] distance
      [3] albedo
      [4] diameter
      № 1 is usually overlooked, but is actually at least as important as the other factors. For instance, if Earth is ‘here’, and there are NEOs (or at least EOCOs … earth orbit crossing objects) on the far side of the Earth-Sun system, well … the sun’s in the way, and we’ll not see ’em. Opportunity isn’t there. Or, if The Program to detect NEOs happens to be scouring a segment … or a hundred segments of the sky which only covers some 20% of the whole evening view, … well 80% of the view we’re blind to.
      Distance is probably obvious: the brightness of an asteroid depends on the distance-squared from US, and the distance-squared from Sol. Combine that multiplicatively with the albedo of the thing, and you get another multiplier range from about 0.05 (like charcoal briquettes) to 0.80 (like dirty snow). But its just a multiplier. № 2 is far more of a brightness driver. № 4, diameter is exactly linear: an object 2× the diameter will have 4× the brightness nominally. All other factors not different.
      NUMERICALLY? As an example – this very object?
      Being an asteroid-belt medium-period highly elliptical orbiter, it ranges from what, inside-of-Mercury’s orbit (less than 0.4 AU) out to the Asteroid belt (greater than 2.5 AU). When it was only 200,000 km away (0.5 Moon orbit distance), it was a 13th magnitude brightness point. Astronomical magnitude is “every 5 is another ¹/₁₀₀th the brightness”.
      IF the object were say 0.1 AU away (15,000,000 km), its absolute brightness wouldn’t be very much different (( 1.0 AU ÷ 1.1 AU)² ) = 83% as bright. However its distance ( 200,000 ÷ 15,000,000 )² = 0.000178 is a whole lot less bright. Down another 9.6 magnitudes. 22.5 mag. One 6800th as bright as the amateur in Austria was able to observe. And that’s only +0.1 AU from where this bad boy most closely approached.
      If it were – let us say – out there … at “aphelion” – the furthest point of its orbit from Sol, about 2.5 AU out, AND Earth was positioned 90° orthogonal to it, you have (D = √( 2.5² + 1² ) = 2.7 AU, and its absolute brightness of (( 1.0 ÷ 2.5 )² = 16% ) of its as-discovered absolute brightness, well … if 1 AU = 375 Earth-Luna distances, then you’re looking at (0.16 × ( 0.5 / (375 × 2.7))² = 1 ÷ 25,000,000 th as bright. 18.5 magnitudes dimmer. 31.5 magnitude.
      To put that in perspective, that is the LIMIT magnitude (for 1-day observations) of the Hubble space telescope. Given that even at the aphelion over the course of a day, the very same asteroid would be moving against the background, it would be invisible. The photons, very few, wouldn’t have time to accumulate as a barely visible ‘dot’ on the Hubble’s fantastically sensitive image plates.
      Here’s a cool calculation for you. At 2.5 AU (aphelion, middle of Asteroid Belt), from a lot of pretty simple physics, one can figure that the object is moving about 5×10⁻⁸ radians per second relative to Sol as the ‘center’. From Earth, even if purely tangential (i.e. across our viewing frame), the object would be moving about 1300 arcseconds/day across the night sky. The Hubble has a resolution of 0.1 arcsecond. Thus the moving object would shed its wan light on (1300 ÷ 0.1) = 13,000 pixels of the Hubble’s best imaging sensors. Thus, each pixel would only receive ¹/₁₃₀₀₀th of the whole-day exposure. If the limit is 31 magnitudes, then this object would have to appear –9.9 magnitudes brighter, or 21.8 mag. Clearly, being only 31 observational magnitude, it would be entirely invisible here.
      Note also that even the might James Webb scope, sensitive down to about 34th magnitude, would ALSO still be unable to observe this new asteroid at the distance of the Asteroid belt. That same –9.9 mags due to motion applies. 34 – 9.9 = 24.1 magnitudes, limiting … at 2.5 AU …
      AND THE FUN PART: which corresponds to HOW BIG? Well, working magnitudes backward, the James Webb ought to be able to barely detect (1 day exposure) NEOs from 1.5 to 3.6 km in diameter at the Asteroid Belt distance. IF fixed on the background stars (i.e. “opportunistic capture”). If the scope tho’ is carefully positioned to slew at 13,000 arcsec/day thru the fixed field, then detection of THIS object … 50 to 110 m in diameter… is possible. Just have to pick a spot, and look at it for a day.
      Whadya bet that other astronomers would be a bit miffed if your team got the 10 billion dollar J.Webb for a whole friggin 24 hours… to slew ever-so-slowly thru the Asteroid Belt in some completely random azimuth in its extent? I suppose if its an economic argument: “you can arrange viewing of whever you like for $750,000 a day”, well money speaks. Who cares where your point of interest lies.
      GoatGuy

      • If one is spotted with our name on it, we’ll never know. The economic consequences would be devastating and therefor kept quiet. I reported this http://www.amsmeteors.org/members/imo_view/report/76090 near miss and even wrote NASA. The response was: “You didn’t see what you saw.”. It’s very hard to scale this, but assuming an altitude of 80 miles, this was a minimum of a mile in diameter. It passed the DEW line and wasn’t seen??? Lots of anecdotes makes me think this was known, two movies (same area and direction as the one I saw), Treaty with Argentina or population transfers, G. Bush buys 150 square miles of Paraguay to “explore for gas” and never does. Obama was on the other side of the world and the Clinton’s were out of town on the night it passed. I stopped trying to find a skycam that may have recorded it. I think it will be back.

    • Is the glass half-full or half-empty? lo
      [The mods note that any glass half-full is twice as big as it needs to be. .mod]

      • With the “near miss” headline and statements in the article, shouldn’t they teach basic logic to journalists and these scientists? If something was a near miss it means that it actually hit the target. “Don’t worry, you missed the shot but I got him because I didn’t miss.” It’s difficult to really trust anything these people say because it makes no logical sense at all.

      • I would have said “close miss” as opposed to “miss”, “far miss”, or “almost missed” ( which might also be called a “hit”) but that requires an assumption about the standard deviation of “miss” – when we don’t know how many of any kind of “misses” have previously occurred in the passed.

      • Surely ‘near Miss’ is sexist? I’m surprised to find such an established, august site as yours propagating such paternalist misogynistic language.
        The correct term used to be ‘near Ms’, but now it has been changed to ‘Person of indeterminate gender’….

    • It missed Earth in a close manner. link
      After spending years arguing with students about the difference between what they wrote and what they swore they meant, I was delighted to teach courses where the answers could be expressed as numbers or equations.

    • NASA: Previously Unknown Asteroid Nearly Misses Earth today

      The title changed to:

      NASA: Previously Unknown Asteroid had a Near Miss with Earth today

      • The real danger is that a closer “near miss” would be interpreted as an enemy attack and prompt a missile launch that then would become reciprocal.
        Congrats to the Russians for not doing so after the last “near miss” that actually entered the atmosphere and created quite some panic on Russia!

      • “Near miss” means missed, but “nearly missed” means hit.

        I would have never guessed that one.

      • “Nearly missed” is the same as “almost missed”, not hard to understand. I almost missed the flight, or nearly missed the flight. He nearly dodged the bullet, unfortunately he didn’t quite and got killed.

    • Well, let me put the “near miss” in perspective. If it crossed Earth’s orbital path within the distance between Earth and the moon, then it missed the earth by less than 5 minutes. If the asteroid had arrived only a few minutes differently it would have gotten a lot more interesting.

      • If that rock 65 million years ago had been a few minutes earlier or later, we wouldn’t be here today. That’s quite a thought.
        If there were any intelligent life on Earth today it would probably be some kind of advanced dinosaur.
        Dinosaurs probably preferred warmer climates. If they would have been concerned about CO2 it would be because there wasn’t enough.
        Chris

      • I do get tired of the kilometric measurements–at least have the courtesy to add the distance in miles, which I estimate to be about 118,000. I’m glad it missed!

      • That’s 5 minutes, assuming gravity doesn’t have an impact on the objects path.
        The closer it comes to the earth, the more the earth’s gravity bends the objects path towards itself.

    • Nearly missed means it hit Earth

      That is probably why they DID NOT say “nearly missed”. They said “near miss” which means it missed but came near.
      If you want to be pedantic, you are not allowed to change what was said first. Dumb.

      • Don’t be too sure.
        An anonymous source at the DOJ reports that Robert Mueller’s team is looking into near collision collusion.

      • That is true. If Trump had been involved it would be on every news stand and broadcast here in Australia.

      • All of that CO2 makes our atmosphere denser, and the Earth’s gravitational attraction for these rocks stronger.
        I need a grant to crunch the numbers more precisely, though…

      • All that CO2 released makes more gasses, makes the atmosphere hotter, the hotter atmosphere expands more, an expanded atmosphere makes more drag in the upper atmosphere than before, which slows the asteroids down more, which makes more of them hit earth – which is now a larger target so its gets hit more which makes the earth bigger, which makes it weigh more, which makes more asteroids get attracted towards the earth so it will hit the earth more, so the earth gets bigger and heavier and expands the atmosphere more ….
        A clear example of positive feedbacks in action.
        And so it’s all Trump’s fault.

  2. I’ve said this before on WUWT but it bears repeating: We have more to fear and much greater potential for catastrophic ‘climate change’ from a rogue asteroid strike on our planet than we have from slowly increasing trace amounts of CO2 or CH4 gas in our atmosphere.

      • it’s easy! For our own protection we must build and maintain a minefield around Earth – each and every person (except our Fearless Leaders of course) on the planet can then be taxed an appropriate amount, enough to establish a bureaucracy, feasibility studies, a couple of dozen working groups and committees, annual meetings in an appropriately pleasant setting, discussion papers, declarations, public awareness campaigns, fighting groups and evaluations.
        Once everyone has contributed all their wealth it will then be determined too costly and while the science was absolutely, rock solid, indisputably resolved and utterly righteous, concerned parties will demand an investigation into what the funding was spent on. The Department of Saving our Arses led by Pinocchio Wasnme having ordered departmental restructuring 5 times due to “concerns” will naturally be tasked with the investigation.
        People then be taxed an appropriate amount – enough to establish a bureaucracy to investigate. A couple of dozen working groups and committees will need forming, annual meetings in an appropriately pleasant setting, discussion papers, declarations, public awareness campaigns, fighting groups and evaluations will be established..
        repeat.

    • Average velocity of asteroid is 20 km per sec, comets tend be about 30 km per second (or faster) so it wasn’t a comet, but could have been a dead comet.
      Anyhow would done more damage compared to typical asteroid of that size.

  3. Maybe it was the Globull Warming that sucked it in… Who wouldn’t want to swing by a nice overheated planet for a quick warmup… It’s cold out there in space…. This is the punishment for planets where the thoughtless inhabitants allow the plant to develop a fever….
    Probably the Russians and Trump colluding to distract attention from their prior collusion….. Colluders do that you know…..
    /sarc off
    All those dollars to watch for “incoming” and they miss a football field flying right at us ???

    • Surely all that extra CO2 in the atmosphere has made our planet heavier. This will draw in more asteroids and comets.
      (That’s sarcasm y’all.)

  4. My daughter was talking over the w/e about the dinosaurs being wiped out by an asteroid strike. I told her that it was just a theory with strong evidence to support it, but a theory none the less. I said the earth has been struck many times in the past but most of that evidence, especially in Australia, is hidden or worn away. I said to see evidence that asteroids do strike, look at the disk of a full moon one night.

  5. And the Liberal MSM heads explode!
    The “space junk” is so fleetingly small by kilogram that you would notice a Bugger long before any piece of Space Junk, by way of comparison!
    A-Ha!

  6. From this news brief I did not get the impression that the path of the asteroid and the earth’s orbit had ever crossed. Would it have crashed on us if it was delayed/arrived by a few seconds/minutes/hours?
    I think a clearer/scarier message would be: “By a few xxx seconds, we were all spared”.

    • Chris, less than earth/moon distance = less than 5 minutes difference in orbital timing. Damn close, if space carried noise I’d say the bullet whizzed by.

      • So it did cross our orbit. Wow that was a close call indeed, just two green lights at an intersection.

    • The minimum orbital intersection distance (MOID) for 2018GE3 is 0.000969 AU which is 145,000 kilometres. The orbital inclination (round the sun) is about 9° to the ecliptic. See JPL’s 2018GE3 page here:
      https://ssd.jpl.nasa.gov/sbdb.cgi#top
      The closer the orbital inclination is to 0° (without actually being 0°) the more it forces the MOID crossing to be (almost) directly above or directly below the Earth’s orbit line. Since 2018GE3 is at 9° inclination its location as it crosses our orbit (going through its MOID position) is almost directly above our orbit line. Hence, the closest it could have got is 145,000km and it would have been at a location almost directly above us, but just sunward of our orbit line (because it was descending when passing us).
      But the actual close approach distance was 193,000km. This is because the Earth hadn’t quite reached its MOID position for GE3. This meant GE3 passed through its MOID position about 70 minutes before we (Earth) passed through our corresponding MOID position. If we had timed it that perfectly we’d have been almost directly under GE3 as it passed. But we were 70 minutes late and that’s why the close approach was at 193,000km and not 145,000km. It’s the hypotenuse of the triangle that includes the ‘vertical’ MOID distance (145,000km) as its opposite side and the ‘horizontal’ Earth travel to get to its MOID position (127,000km).
      The upshot is that if GE3 had been delayed by about 70 minutes, the Earth would have been at its MOID position, almost directly under GE3 as it passed over our orbit line. And the close approach would thus have been 145,000km. That’s the closest it could have got to us.
      I try to link very close approachers, like GE3, to concurrent meteors because there’s increasing evidence they can come with companions that have fragmented off. The key to this process is the retarding process explained above i.e. placing the fragment behind (or in front) of the main asteroid along its orbit so that it’s arriving at the MOID at the same time we (the Earth) do…but then this hypothesised fragment is also offset by the MOID distance so that it hits the Earth. Its trajectory in the atmosphere at the latitude/longitude of the known meteor is modelled and compared to that of the meteor itself.
      The MOID distance can change due to close approaches with Earth and long-term precession of Earth and asteroid as well as remote perturbers such as Mercury, Venus, Mars and Jupiter. 145,000km is very close so it could get nearer or farther over time.
      Many small (5-20 metre) close approachers fly within a few tens of thousands of km of their MOID position at close approach. This is always an amazing coincidence, a chance in several hundred thousand over an orbit of a few billion km. But the fact it happens so often shows that these are the few flukey lottery winners and it points to a population of millions of 5-20 metre asteroids.

  7. Lucky it missed the moon as well.
    Hitting that could possibly have far reaching effects here. With no atmosphere to burn up large asteroids or even parts of them an impact must be far greater on the moon. Putting a wobble on it could play havoc here with tides seasons and weather.

    • Of course, if it barely missed the moon, it could have deflected to hit us. There’s even a remote possibility it could have been captured into Earth orbit.

      • Would perhaps require some orbital/atmospheric energy absorbing. Pretty damn slim chances, but its happened before. Space is big and time is long.

    • The moon gets hit all the time. Take a look. Smooth areas are…rare. Lunar orbital satellites will see the back side for us now.
      It wasn’t big enough to cause an issue even if it hit.

    • You have to consider relative masses. It may have added or subtracted a couple of micro-seconds from the time it takes the moon to make a complete orbit of the earth, but that would be it.

    • Please. A rock that size will have no measurable effect on the orbit of the moon about the Earth. Please try to get a sense of scale and numeracy.

      • You have to consider instead whether the moon could have had a measurable effect on the orbit of the “rock”.

  8. NASA is far too busy “normalizing ” temperatures than to worry about a pesky asteroid .
    Canada’s Prime Minister was concerned about it’s gender and buying an uneconomic pipeline from a former Enron wheeler dealer . Can another Ontario energy debacle be far behind ?
    Whew what a relief…. budgets balance themselves in the land of silver spoon socialists and 10 billion dollar pipelines are flipped by a company with a whopping under $2 billion in rate base . Now that is sweet unless you are a Canadian tax payer that is going to wear this shit show .
    .

  9. We live in a pinball machine without the flippers to send objects flyong back to heavens. But the small size of even regionally destructive space rocks means we have to accept our fate to chance until we can do do more than say “The sky is falling” which does no one any good bad cause an unneeded panic.

  10. We need to unleash the asteroid miners. While this particular rock is in an obit that makes it a poor prospect for mining, their searching should identify a number of potentially hazardous asteroids, not restricted to easily reached orbits.

      • What would be more valuable is if asteroid had water. This rock probably had water, but it’s trajectory is nearly impossible to reach it due the inclination of it’s orbital plane (which is common problem with rocks passing near Earth).

      • Given how close it passes to the sun on each orbit, if it once had water, I doubt any remains.
        It doesn’t have to be diamonds or gold. Given how much it costs to lift anything into orbit, any material already in orbit becomes very valuable.

  11. “Despite coming directly away from the sun, it was not discovered until 14 April 2018, one day before closest approach on 6:40 UTC 15 April 2018. It passed Earth at a nominal distance of 0.50 LD (0.00128 AU) which corresponds to a distance of 193,000 kilometres (120,000 miles). It passed even closer to the moon, 0.34 LD (0.00087 AU). After closest approach its apparent magnitude dropped from 12 to 35 in less than 12 hours, heading straight towards the sun. Coming from the opposite direction, it would have been impossible to observe before its approach. ”
    Hmm, when it was first seen, probably could not determine if it would not hit earth (though that is typical if don’t know what is) but first few hours of looking it would indicate it could hit Earth, and at some point, one would know it not going to hit. Or probably, it was frantic for a few hours.

    • If it’s heading straight for the sun, won’t it collide with it? How big a sunspot (sunsplash) would it make? Can telescopes or other instruments follow its progress and record the impact? I’d be interested in seeing that.

      • It is heading straight towards the sun from our perspective. In reality it is coming in at an angle, steep, but still an angle, which puts it into a highly elliptical orbit. And even if it did head right into the sun, it would burn up long before reaching the surface. It is just too small compared to the Sun to have any kind of noticeable effect in any event.

  12. What the heck is happening????? Over on the PBS commentary, my comment was repeatedly kicked out and channeled to WordPress. My comment above is also awaiting moderation.

  13. The irony if we are hit by an astroid.
    All our officials are preparing for Global Warming.
    We huddle here at the bottom of this gravity well,too timid to look out.
    Funny how human “leadership” works.
    One is a near certainty,the other an unmeasurable delusion.
    But how can you tax the citizens for Asteroid prevention?
    The other requires no real plan or expenditures as there is nothing to fear.
    But an asteroid dropping in is impossible to explain away, if you misspent all the moneys on your personal self enrichment and comrades.

    • John,
      Yes, it would be ironic if an asteroid extinguished human life before CAGW had a chance to do it. Governments might not even have a chance to spend all the carbon taxes they collect. All the liberal sarcasm would have been for naught.

  14. It was a near miss astronomically, but not ballistically. The cross sectional area of the Earth makes up about one tenth of one percent of the area within 192,000 km. On average, only one of every thousand asteroids that pass this close or closer will hit the planet.

  15. “Average velocity of asteroid is 20 km per sec, comets tend be about 30 km per second (or faster) so it wasn’t a comet, but could have been a dead comet.”
    A “dead comet”????
    What does a “live comet” look like?
    Do they go out on dates, and breed? Is there a “metoo” movement for ugly comets?
    Does a comet that impacts the earth get an Oscar?
    The questions just keep coming……………..!

    • “There are many physical mechanisms that can limit the dynamical lifetime of a comet (or in other words the period of time the comet is active). In fact, the typical dynamical lifetime of a comet is about 1/2 million years. After this period, the comet is no longer active, and becomes a dead comet.”
      http://spaceguard.rm.iasf.cnr.it/NScience/neo/neo-what/com-life.htm
      The lifetime of asteroids or comets which come near Earth is few million years.
      NEO is a Near Earth Object which is asteriod, or comet. And an asteroid can be a dead comet.
      Also from above ref:
      “Furthermore, scientists think that perhaps half of the near-Earth asteroids may be “dead” comets. ”
      And a dead comet which doesn’t t get warmed up much from the sun, can still have water remaining which wasn’t out gassed when it was a comet. Or it have good chance of water remaining beneath the regolith of surface of the dead comet, particularly if it recently died (say within the last 100,000 years).

    • William………………..YOU of all people SHOULD KNOW the answer to THAT QUESTION !
      What does a “live comet” look like ?
      Go to youtube and look at YOUR NAMESAKE Bill Haley and his Comets singing …………….
      VERY APPROPRIATELY i’m sure you will agree…………..”Rock around the clock ! ”
      RSVP

  16. A known unknown. Then there are the unknown knowns that lie beyond the edge of our solar system, which reduce fidelity of transmitted signals in the near-frame (i.e. scientific domain).

  17. There will be many more surprise asteroids. One day, there will be one that will end life on Earth as we know it. This will happen within the next 500,000 years. Or it could happen tomorrow. There is evidence to show every ~60 million years we get smashed. I believe the best answer is when the solar system crosses the galactic plane every other 30 million year period, many asteroids are dislodged from the Oort cloud by the increased galactic gravity. The ~60 degree tilt of the solar system to the galactic plane sends them on a 1-3 million year journey towards the Sun. Unfortunately for us, the Earth gets in the way. When they do come, they will appear with only a one to three day warning from the direction of the Sun as they swing around it. About 60 million years ago, they helped us escape the dominance of the dinosaurs. The next time they will just kill most of us in preparation for the next dominant species to claim the planet. The Solar System crossed the plane about 2-3 million years ago. It’s time for them to increase in size and quantity. The surprise sightings, especially the ones from the direction of the Sun, are the first indications of the asteroid swarm to come.

  18. CAGW is causing an increase in close encounters with deadly astroids by some unknown attractive power. A computer model will be created forthwith. But either way we are doomed!

  19. It would have been very bad timing if it hit the earth in the wrong place with the force of a hydrogen bomb today.

    • “The small asteroid that broke up over the city of Chelyabinsk, Russia, on Feb. 15, 2013, was a … The energy of the resulting explosion exceeded 470 kilotons of TNT.”
      And
      “The Tunguska impact of 30 June 1908, which destroyed 2000 square kilometres of conifer forest in a sparsely populated region, the Central Siberian Plateau, had the energy of a large hydrogen bomb”
      Wiki:
      “Early estimates of the energy of the air burst range from 10–15 megatons of TNT (42–63 petajoules) to 30 megatons of TNT (130 PJ),[7] depending on the exact height of burst estimated when the scaling-laws from the effects of nuclear weapons are employed.[7][8] However, modern supercomputer calculations that include the effect of the object’s momentum find that more of the energy was focused downward than would be the case from a nuclear explosion and estimate that the airburst had an energy range from 3 to 5 megatons of TNT (13 to 21 PJ). ”
      https://en.m.wikipedia.org/wiki/Tunguska_event
      Above article:
      “Based on the intensity of its reflected sunlight, 2018 GE3 must be 48 to 110 meters wide, according to NASA-JPL.
      This puts it into the same class as the 60-meter Tunguska impactor that leveled a forest in Siberia in 1908. ”
      If it was 48 meters it would like Tunguska, and if 110 meters probably close to the Tsar bomb or
      larger.

  20. I once bought a fish finder for my boat and had been happily using it. then one day I had some kids on the boat and noticed we were in the midst of some of the best fish I had ever witnessed on the sounder.
    We fished vigorously for some time before noticing that a tech savvy child had set it of in demo mode which has a very optimistic disposition.
    That is NASA in demo mode looking for big rocks in space. Was there even a rock or was it a model generated rock. Would we even know, we live in a virtual climate generated by models is this the same, it reminds me of the game “second life” or some such name where you can be whatever you wish.

    • It was at that moment I hooked something big, though there was no fight in it. Soon I had hauled into the boat a silt-encrusted, somewhat corroded version of the same model fish finder with a cracked screen. “Maybe this one was set to demo mode as well,” I mused aloud, then glanced to see my own’s screen had turned a solid bright red. There were insistent taps on the hull, and we looked over the side to see many glowing rectangles rising in the murk. Some were larger than others. “Toss it back!” My mate cried. “Hell, toss ’em both!” But it was too late. The rectangles were now dark silhouettes against scattering sideways as a much larger greenish glow rose from the depths. It was enormous enough to span our boat, and as it neared the surface we could see the familiar icons to one side, and in the same area that had displayed the shoal of phantom fish that brought us to this fateful spot, there was, “Oh my God…
      …” a cartoon shape of a boat on this evil screen. A giant steel hook exploded out of the water and hooked the side of the hull, and the boat tilted suddenly…

  21. Some further discussion on Twitter between these three accounts including very good simulated views of GE3 passing us and other more detailed stuff
    @tony873004
    @Tom_Ruen (contributed graphics to the Wiki article)
    @scute1133 (me)

  22. Rocket scientist – I want to address the very accurate appraisal of how difficult it is to pick up thes objects that you gave and the threat that one day we are likely to get hit. While I agree with everything you said, I do not think we need remain quite as helpless as we are.
    It would not be beyond our abilities to launch automated satellites into orbits at various positions around the Earth’s annual orbit equipped with camera scopes to help pick up these smaller but potentially very dangerous objects by broadening our view of the space rock environment. In the long term we might even think of putting into orbit satellite rockets designed to knock smaller objects off a collision course with Earth rather than putting into orbit rockets designed to fall on us.
    Of course this would be very expensive and certainly wouldn’t protect us from everything, but it would improve our chances. Perhaps it would be a better use of the trillions being utterly wasted on a colossal climate lie. It would also bring together the huge talents of people worldwide. But then I remain an optimist about people and nations , unlike the souless hatred of humanity all too evident in the green-eco movement which is determined to bring more misery to billions.

  23. Since this substantial chunk swings by inner-system planets to solar perihelion from the Mars – Jupiter asteroid belt approximately every 2.5 years, how is it that NASA et al. have not previously marked its orbit?
    Even by today’s rudimentary standards, you’d think that blanket surveillance of such objects would not be all that difficult. If Earth’s Oort Cloud of commercial/military/scientific satellites did not register this interloper, it can only be because no-one is looking.

  24. Objects have been flying past the earth since Creation. We are just recently able to detect/see them. A big’un could hit us today, or it may be another 10,000 years.
    Get over it.

  25. We have to have several Orion class spaceships ready on low Earth orbit. Only those could produce acceleration enough to intercept surprise celestial bodies, especially ones coming directly from deep space. However, this one is not of that kind, so setting up a serious catalog of near Earth objects is a priority anyway.
    That’s one of NASA’s jobs. While climate research in general is not, only launching &. operating satellites to collect &. share climate data.
    https://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)

    • “We have to have several Orion class spaceships ready on low Earth orbit. Only those could produce acceleration enough to intercept surprise celestial bodies,”
      Lasers don’t need to intercept the orbit of incoming asteriods. They can reach out and touch asteriods and comets in all sorts of positions. Immediately upon discovery, if necessary, no wait times required.

  26. If it’s not CO2 and has no carbon taxation potential, then it must not be dangerous.
    There was a similar quote about this from a grazing dinosaur in a previous era of controversy between meat eaters and plant eaters.

  27. Perspective: Lets say the rock was 100 meters wide to make the math easy. It passed by the Earth 192,200 kilometers away. The diameter of the Earth is 12,756 kilometers. If we move the decimal point 4 spaces to the left on all the numbers, that gives us a bullet size object missing a 1.2 kilometer size object by 19.2 kilometers.
    Most people have no fear of a gun being fired 12 miles away. I am not sure why we call this a close call!

    • If you read the comments above, you will see that the distance by which it missed is equivalent to 5 minutes orbital travel time of the earth. If it had arrived 5 minutes sooner (or later, I am not sure which it is) it would have hit.
      That is five minutes in the one year orbit time of the earth. That seems pretty close to me.

      • “A clear and present danger….” that many will try to minimize regardless.
        ‘Whistling past the graveyard’ ….. indeed!

      • “If it had arrived 5 minutes sooner (or later, I am not sure which it is) it would have hit.”
        “If” is doing a lot of work there.

  28. NASA has been faking space travel, satellites, ISS,fear mongering the world with near miss asteroid claims, fake Hubble photos, fake photos of Earth from space. How can anybody take these scam artists and frauds seriously?

  29. Around 1998 candidate Donald Trump in an interview about the arms-race mentioned Reagan’s shield, known as SDI. Maybe PUTUS now could be advised to put that back on the table when he meets Pres. Putin – after all he wants to stop the arms-race (unlike the swamp and Prime Minister May(day).

  30. Good news in the long run: My grand children will mine it and live within a large rotating cylinder built from it.

  31. If you watch the NASA animation from the link above, June 13, 2023, Mercury could be struck. Wouldn’t take much of a deviation in speed to make that happen.

  32. Surely it’s regular orbit is now thoroughly disturbed? Passing that close to the Earth may have wound up its speed considerably. That slingshot thing.
    True danger lurks.

    • It was close enough that they should have been able to get a good fix on it’s current trajectory. From that they should be able to get a pretty good idea what it’s next dozen or so orbits will look like.
      Now that we know where it is, updated orbit tracks can be taken every decade or so as well.

      • MarkW

        It was close enough that they should have been able to get a good fix on it’s current trajectory. From that they should be able to get a pretty good idea what it’s next dozen or so orbits will look like.
        Now that we know where it is, updated orbit tracks can be taken every decade or so as well.

        Maybe, maybe not.
        Look at Comet Shoemaker-Levy 9. Spotted only AFTER it broke apart after a close pass-by of Jupiter. They could not “back-calculate” even its second-to-last orbit close enough to actually determine how it tracked before breaking up: Only general estimates. And that with the relatively simple n-body problem of Jupiter, its closest 4 moons, and the single comet body. (Before breakup.) After break-up the smallest 26 smaller fragments quickly grew near-invisible, untrackable – and that with a well-known of their bigger brothers and sisters to track.
        https://www.google.com/imgres?imgurl=http%3A%2F%2Fplanet.racine.ra.it%2Ftesti%2FFoto%2Fh_csl9.jpg&imgrefurl=http%3A%2F%2Fplanet.racine.ra.it%2Ftesti%2FFoto%2Fh_csl9.htm&docid=2al4JVjU1bct7M&tbnid=TW3CrflWlobhEM%3A&vet=10ahUKEwj7zuOKgsDaAhUCwVkKHcPtAIcQMwh1KDIwMg..i&w=640&h=480&hl=en&bih=698&biw=1092&q=shumaker-levy%209&ved=0ahUKEwj7zuOKgsDaAhUCwVkKHcPtAIcQMwh1KDIwMg&iact=mrc&uact=8
        The collision bursts of gas and dust in Jupiter’s atmosphere of every fragment were each far larger than the diameter of earth. So even a single “invisible” comet breakup fragment would be truly catastrophic events. But not as profitable as carbon futures trading, so the enviro’s don’t care, won’t fund that NASA research.

  33. Surely it’s regular orbit is now thoroughly disturbed? Passing that close to the Earth may have wound up its speed considerably. That slingshot thing.
    True danger lurks.

  34. If an asteroid big enough to destroy a civilization hasn’t hit earth in 5000 years of recorded history, why should we be worried about one hitting earth any time soon?

    • Stochastic variation.
      Of course, we may not get hit for tens or hundreds of years.
      Nobody knows. [Well, I certainly don’t!].
      Auto

    • Such collisions are purely random events. Getting hit tomorrow is just as likely as getting hit some day 10K years from now.
      The only thing we know for certain is that the longer the time period in question, the better the chances of getting hit become.
      BTW, the Tunguska event was big enough to wipe out an entire city. We are fortunate that the place it did hit had very low population numbers.
      If the Russian meteorite of 2 or three years ago had been a few feet bigger across, it would have done many times more damage. We were fortunate that it was on the small side.
      Didn’t the meteor that created Meteorite crater in Arizona hit about 5K years ago? Wouldn’t have ended civilization as a whole, but it would have ended it anywhere within 100 miles or so of the impact spot.

      • Posted elsewhere:
        The April 15, 2018 near fly-past was by a meteoroid about 80m in diameter, roughly the same size as the 1908 Tunguska air burst that levelled ~2000 square kilometres of Siberian forest – a circle about 50km in diameter.
        The April 15 meteoroid would probably have broken up in the atmosphere, like the Tunguska impact. The airblast would be like a modern nuclear bomb. No big deal, unless you are close to the large airblast area – and then even a good umbrella would not help you. The airblast would easily take out a large city and its surrounding metropolitan area.
        Here is a damage calculator for asteroid impacts (h/t to Jeff): http://www.purdue.edu/impactearth/
        https://en.wikipedia.org/wiki/Tunguska_event
        The Tunguska event was a large explosion that occurred near the Stony Tunguska River in Yeniseysk Governorate
        (now Krasnoyarsk Krai), Russia, on the morning of 30 June 1908 (NS).[1][2] The explosion over the sparsely populated Eastern Siberian Taiga flattened 2,000 square kilometres (770 square miles) of forest, yet caused no known human casualties. The explosion is generally attributed to the air burst of a meteoroid. It is classified as an impact event, even though no impact crater has been found; the object is thought to have disintegrated at an altitude of 5 to 10 kilometres (3 to 6 miles) rather than to have hit the surface of the earth.[3]
        The Tunguska event is the largest impact event on earth in recorded history. Studies have yielded different estimates of the meteoroid’s size, on the order of 60 to 190 metres (200 to 620 feet), depending on whether the body was a comet or a denser asteroid.[4]
        https://www.gettyimages.ca/detail/news-photo/photograph-from-the-tunguska-event-was-a-large-explosion-news-photo/629465421?#photograph-from-the-tunguska-event-was-a-large-explosion-that-near-picture-id629465421

  35. MarkW April 16, 2018 at 7:12 am wrote
    Greg, I’m sure your attempts to make Putin and Russia look better are appreciated. Somewhere.
    I think Trump has cornered that market.

    • There is a claim out there that Russian internet trolling has increased 2000 percent since Trump raided Syria the other day. I guess we should keep our eyes open for disinformation from that group.

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