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."
Re:How Much Damage? (Score:5, Insightful)
Since it claims objects that size impact Earth about once every 5 years, the damage would be the same that we see every time one of these impacts. If you can't think of the last time that happened or you can't think of a damage report about that, then that should be your answer.
Re:OH NOES!!! (Score:3, Insightful)
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:How Much Damage? (Score:4, Insightful)
Regardless, a post farther down links to an impact calculator that claims it bursts in mid-air and results in no significant impact, so this speculation is moot (I am assuming the calculator is well-written).
Re:How Much Damage? (Score:5, Insightful)
Re:OH NOES!!! (Score:5, Insightful)
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:OH NOES!!! (Score:5, Insightful)
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?
Re:OH NOES!!! (Score:3, Insightful)
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.