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Space Science

Unknown 7m Asteroid Almost Impacted Earth 289

xp65 writes "A previously undiscovered asteroid came within 14,000 km of Earth — just over one Earth diameter, 1/30 the lunar distance — on Friday, and astronomers noticed it only 15 hours before closest approach. On Nov. 6 at around 16:30 EST, a 7-meter asteroid, now called 2009 VA, came only about 2 Earth radii from impacting our planet. This is the third-closest known non-impacting Earth approach on record for a cataloged asteroid. The asteroid was discovered by the Catalina Sky Survey and was quickly identified by the Minor Planet Center in Cambridge MA as an object that would soon pass very close to the Earth. JPL's Near-Earth Object Program Office also computed an orbit solution for this object, and determined that it was not headed for an impact." The article notes, "On average, objects the size of 2009 VA pass this close about twice per year and impact Earth about once every 5 years."
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Unknown 7m Asteroid Almost Impacted Earth

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  • Way to sensationalize an asteroid that isn't much bigger then a womprat. If it had hit the Earth, very few people (if any) would have even noticed.
    • Re:OH NOES!!! (Score:4, Interesting)

      by Absolut187 ( 816431 ) on Tuesday November 10, 2009 @03:33PM (#30050102) Homepage

      I think the *point* is that we didn't know about it until 15 hours before its closest approach.

      The obvious implication being that there could easily be many more out there, possibly much bigger, and possibly on a collision course with earth.

      We just dodged a bullet, and you're basically saying "so what, it would only have been a flesh wound anyway".

      We had this same discussion [] a few months ago, and it seems like most people on Slashdot think this is no big deal. I hope they are right, because we sure don't seem to be doing much about it.

      • Re: (Score:3, Insightful)

        by blueg3 ( 192743 )

        This seems like a nonsensical conclusion -- larger objects are easier to detect, both by virtue of being larger and, since they are a potential threat, are more worthy of attention and effort.

        • Re:OH NOES!!! (Score:4, Informative)

          by Absolut187 ( 816431 ) on Tuesday November 10, 2009 @03:42PM (#30050242) Homepage

          They're only easier to detect if you're looking in the right direction.

          If you've only surveyed a small fraction of the relevant space, you've likely missed all objects of ALL sizes.

          According to NASA they are tracking 90% of 1km NEOs, but they aren't satisfied with that and neither am I.


          • Re:OH NOES!!! (Score:5, Insightful)

            by Nyeerrmm ( 940927 ) on Tuesday November 10, 2009 @04:34PM (#30050938)

            This does not indicate a question of looking in the right direction. Seeing something that small is basically impossible until its right on top of us even if you're looking straight at it, which is fortunate since its not a big concern. Compare a 7 meter asteroid with a 300 meter asteroid such as 99942 Apophis:

            Since surface projection is proportional to the radius squared, Apophis is likely to be 100,000 times brighter, or around 12.5 stellar magnitudes. During the 2029 close approach, when Apophis will be within the geostationary belt, it will be magnitude 3.3, meaning that a 7-meter asteroid would be around magnitude 16. This is below the limiting magnitude of most telescopes being used in these searches, so only the very large (1+ meter) would be able to find it even when that close.

            Also, there are a number of individuals doing this in addition to the official NASA work. This was processed through the Minor Planet Center in Cambridge, to which it is quite easy to submit information on new asteroids. With automated amateur equipment (the well-funded 60 year old amateur, not the $200 14 year old amateur) its quite easy to set up a system to automatically observe a region of sky and detect asteroids. If you have a series of plates indicating an asteroid, they can be submitted to the MPC through automated software and its all logged. You may not be satisfied, but its certainly not nothing, even if the NASA effort itself is underfunded.

            • Re: (Score:3, Informative)

              by chgros ( 690878 )

              Apophis is likely to be 100,000 times brighter
              (300 / 7)^2 = about 1,800, which is not very close to 100,000

              • Re: (Score:3, Insightful)

                by Nyeerrmm ( 940927 )

                You're right. I accidentally typed in (300*300/7*7) instead of (.../(7*7)). Mea culpa.

                At any rate, its around 10 stellar magnitude off, which means it would be around magnitude 14 on a very near approach. This is just barely visibile in a 16" telescope, so its still very hard to see.

            • Re: (Score:3, Informative)

              by apoc.famine ( 621563 )

              As a comparison for the non-astronomers:

              In college, we had a pretty sweet 0.8m diameter scope. The limiting resolution of that was about 12 magnitude. Magnitude goes up as powers of ten. So 16th magnitude would be 10^4 times dimmer than what we could see with that scope. Even a 1m scope would have issues with that. You'd need fantastic conditions and very, very good mechanics to be able to take exposures long enough to reliably capture 16 magnitude.

              Take into account that we can only reliably

        • Objects, large and small, can only be detected by looking for them. We haven't been doing much of that.
          • Re: (Score:3, Informative)

            by blueg3 ( 192743 )

            We track 90% of the near-earth objects that have a possibility of causing global catastrophe. While there's certainly room for improvement, we've actually been doing quite a lot of looking.

            To give a sense of scale, global-catastrophic asteroids are 1 km in diameter; this one was 7 m.

            • If we know we're tracking 90% of NEOs, why not the other 10%? Isn't it more likely that number was just made up to give a false sense of security? I remember back in the 90s after the Shoemaker-Levy collision there was a brief increase in funding to NEO tracking; IIRC it didn't last past the end of the decade. And considering the state of this page [], I don't have a lot of confidence in their efforts.
              • by blueg3 ( 192743 )

                Isn't it more likely that number was just made up to give a false sense of security?

                Knowing NASA, no. Is there some component of your argument that isn't just baseless speculation?

                This site is better, by the way: []

              • Re:OH NOES!!! (Score:5, Insightful)

                by realityimpaired ( 1668397 ) on Tuesday November 10, 2009 @04:56PM (#30051256)

                If we know we're tracking 90% of NEOs, why not the other 10%?

                Because we don't actually know we're tracking 90% of NEOs. We estimate that we're tracking 90% of them. We can't actually know we're tracking them, because we simply haven't discovered them all. (comparatively) tiny objects in a slow orbit that may cross our own orbit at some point in the future, but that are so dark that they're black, and so cold they're hard to tell from the ambient radiation on the infrared and other bands? The unfortunate reality is that we just can't see some of what's out there, either because we haven't looked in the right part of space with the right equipment, or because the right equipment doesn't exist.

                We figure we're probably tracking about 90%, based on our estimates of the mass of the solar system and how much of what we're actually tracking. We could be tracking 100% of the stuff that actually poses a threat. We could be tracking 50% of it. But the best guess we actually have is that we're somewhere around 90% at the moment, and that the number will go up over time. But we still might never see the one that wipes us out.

                Perhaps a better question is: if we can detect the one that's about to hit us, are we likely to be able to do anything about it?

              • If we know we're tracking 90% of NEOs, why not the other 10%? Isn't it more likely that number was just made up to give a false sense of security?

                OMG, CONSPIRAZY!!!1!1!!ELEVEN!!

                You don't get your search-for-planet-smashers budget increased by underestimating the number of objects out there - if NASA were going to start pulling figures out of their collective asses, they'd overestimate. Luckily, though, we have this thing called "science" which means that such estimates are generally derived using the best available data, and the results are published so that others can review the methodology and confirm or challenge the results. The estimates which

            • Although, to be fair, even if we did spot one, it's not like we can jump out of the way or anything.

      • To quote Billy Bob Thornton in the movie Armageddon:

        Well, our object collision budget's a million dollars. That allows us to track about 3% of the sky, and beg'n your pardon sir, but it's a big-ass sky

    • by mrdoogee ( 1179081 ) on Tuesday November 10, 2009 @04:06PM (#30050584)

      Womprat = 2m

      Asteroid = 7m

      If by not much bigger you mean nearly triple the size... then yes. It's not much bigger.

      this has been you Star Wars nitpick of the day. Thank you.

    • what if we didn't see a 20m asteroid? how about a 100m asteroid? this 7m one makes us think about those possibilities as a completely valid concern

      fear mongering is a big problem in this world. but the antidote to fear mongering is NOT complete imperviousness to fear. that's just as idiotic as fearmongering. what you need is balance between panty twisting hysteria and unresponsive inertia

      fear is a healthy emotion. it keeps you alive. its a valid motivation, when combined with intelligence

      so the proper respo

  • wah! (Score:5, Funny)

    by thhamm ( 764787 ) on Tuesday November 10, 2009 @03:27PM (#30049990)
  • Dang! It's the third time they try to ship my package and miss; I've had enough... And so much for the "confidential" packaging!

  • by Conchobair ( 1648793 ) on Tuesday November 10, 2009 @03:29PM (#30050040)
    Seven meters just isn't all that big. According to the Earth Impact Effects Program [] using typical data: No crater is formed, although large fragments may strike the surface. The air blast at this location would not be noticed.
    • by vvaduva ( 859950 )

      It would sound much more sinister and dangerous if they start reporting these sizes in feet and inches. :)

      • It would sound much more sinister and dangerous if they start reporting these sizes in feet and inches. :)

        ...and its mass in stone.

        • by vvaduva ( 859950 )

          Hehe - that may work the other way around...everyone would be so confused to the extent that we just shrug off the danger and stop stressing out about things that "almost" kill us all on a daily basis.

    • Re: (Score:3, Informative)

      by DerekLyons ( 302214 )

      I was about to say - missing a 7 meter asteroid passing at that distance is roughly akin to missing a pea in the middle of the highway you're currently doing 60MPH down. In rush hour traffic.

    • Uh... I punched in some numbers and got a figure of 24 kilotons for the air burst. That's ... a Hiroshima bomb, give or take. I have trouble believing that people wouldn't at least hear it, even if it popped, as the estimate says, at 121,000 feet.
      • by vlm ( 69642 )

        I have trouble believing that people wouldn't at least hear it, even if it popped, as the estimate says, at 121,000 feet.

        That is 24 miles away, vertically, through "atmosphere" that qualifies as a pretty decent vacuum.

    • The airburst would unleash about 130 tons on TNT [], about 10 times the size of the Hiroshima bomb.

      • OK, say it's 10 Little Boys. Somebody on the ground is definitely going to notice that. I think the calculator's got some fuzzy math going on, 'cause I've been fiddling with it for a few minutes and I came up with this:

        Distance from Impact: 1.00 km
        Projectile Diameter: 70.00 m (10x the size of our rock)
        Projectile Density: 3000 kg/m3 (dense rock)
        Impact Velocity: 45.00 km/s
        Impact Angle: 45 degrees
        Target Density: 2500 kg/m3
        Target Type: Sedimentary Rock
        The project
      • by blueg3 ( 192743 )

        The asteroid is quite unlikely to unleash any trinitrotolulene.

      • by cpotoso ( 606303 )
        I presume you meant 130 kilo tons, and that would be ca. 6 Hiroshima bombs. 130 tons is not that much...
      • The airburst would unleash about 130 tons on TNT [], about 10 times the size of the Hiroshima bomb.

        What and the who now? Little Boy was 13+ KILO tons. That's 1,300 tons. That puts your asteroid impact at one third the blast, meaning you're off by a factor of 100.

    • by elrous0 ( 869638 ) * on Tuesday November 10, 2009 @05:08PM (#30051448)
      Well, we Americans are scared as hell. For all we know, 7 meters could be HUGE!
  • If the threat were 7m asteriods, no one would be monitoring. We'd certainly not be talking about the possibility of mass extinction. Yes some people might die, just as some people die every day. The reason to monitor near earth asteroids is the big ones that can kill off most of the life on our planet in a very short period.

  • by ( 1563557 ) on Tuesday November 10, 2009 @03:48PM (#30050328)
    Join the Mobile Infantry and save the Galaxy. Service guarantees citizenship. Would you like to know more?
  • I think I need a car analogy to fully understand this story.

    • Re: (Score:3, Funny)

      by natehoy ( 1608657 )

      Say you're a new galactic overlord driving a car, but you're in space, and you're drunk. You see this big blue planet getting bigger and bigger in your windscreen. At the last possible moment, you hear me yelling to get the hell off my lawn, you suddenly swerve, and miss. But you've ruined Cowboy Neal's tulips, you insensitive clod!

      • Oh, and PS: This happens twice a year. And about every five years, you don't swerve fast enough.

          (this is the "hauling a trailer" part of the car analogy).

    • An asteroid about the size of a large pickup truck. Does that work?

    • You almost got hit by a kid on a tricycle going really fast.
      He missed you. If he'd hit you, you wouldn't have really been hurt.

      A bunch of people watching laughed, and said "hey, look at the guy, he didn't even see that tricycle until it almost hit him."

      You (hopefully) feel a little embarassed and decide you should probably pay more attention to vehicles of all sizes that might be headed your direction.
      Including big cars that could kill you and your whole family (and 99% of all life on earth).

  • Pssh. 7 meters? Come on outer space, for all your terrifying voidsomeness you sure aren't flinging much in the way of horror our way. What's this I heard apparently Apophis now isn't even a threat. And the Tunguska incident? Hate to break it to your outer space, but nobody was living int he area you hit. Yeah and you'll probably point out the dinosaurs. Sure sure. Let's see you land a decent hit a little more often then every few million years.
    What's wrong outer space? Having trouble hitting a mote of dust

  • A 7-meter wide asteroid isn't very big and would almost certainly explode high up in the atmosphere, causing no damage on the ground, except for random meteorites that reach the ground. For that sized object, I would paint a bull's eye on my roof so I would get to see a nice show.

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