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Unknown 7m Asteroid Almost Impacted Earth
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."
Anybody want to weigh in?
You expect nerds and geeks to give their actual weight online?!
a flying rock! call a geoligist!!!
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.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
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.
From Wikipedia:
If it hit near the center of a large city it could really suck; however, most of the earth's surface is covered by water, desert, mountains, or rural areas, and thus most asteroid impacts of this size do not cause massive loss of life.
Nonaggression works!
It would most likely bursts into a cloud of fragments at an altitude of 8980 meters. Minor local damage might occur if a larger fragment happens to hit a house.
http://www.lpl.arizona.edu/impacteffects/cgi-bin/crater.cgi?dist=0.001&diam=7&pdens=&pdens_select=8000&vel=17&theta=45&tdens=2500&tdens_select=0
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TFA says 7 meters - which is still 30% smaller than what you quote. 30% off a hiroshima bomb is a lot. Not to mention that the composition of the object has quite an effect as well. I'm going to let a source that carries a little more weight to, well, weigh in on it.
What? I can't assume Occam's Razor was a slick fold-up scooter?
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Are you kidding? That thing can't even stand up to a bird with a bagel.
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You can use this site to get an estimate.
And I forgot to consider that this was an object of 10 meters or so when it impacted Earth and was thus likely far bigger before entering the atmosphere. An object that was 10 meters before entering the atmosphere would, depending on composition and angle of descent, likely burn away completely before reaching ground. But there might be a midair explosion or fireball sufficient to ignite highly flammable structures.
Nonaggression works!
The energy would correspond to the mass rather than the radius; assuming constant density we can use volume so 7^3/10^3=0.343 or 34% of the energy of the 10m asteroid. I don't know my meteor impact science, but I wouldn't be surprised if the higher surface/volume ratio means proportionally more of it burns up in the atmosphere to reduce the impact energy even further.
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).
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I'm sure if it had been on course to hit Earth, it would have burned up in the atmosphere and whatever's left would be no bigger than a chihuahua's head.
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AKA Not Much
Unless it lands on your house!
Error reading device 'Signature'. (A)bort, (R)etry, (F)ail?
Would it penetrate through to basement depth? If not most people here wouldn't notice till the next meal didn't show up.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Depends. Is there a modifier for a sneak attack?
yeah, +3 HOLY SHIT A FUCKING METEOR!
"I disapprove of what you say, but I will defend to the death your right to say it." - Evelyn Beatrice Hall, re Voltaire
I think the official name is a "Basement Level Event"
// MD_Update(&m,buf,j);
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.
It would most likely bursts into a cloud of fragments at an altitude of 8980 meters. Minor local damage might occur if a larger fragment happens to hit a house.
http://www.lpl.arizona.edu/impacteffects/cgi-bin/crater.cgi?dist=0.001&diam=7&pdens=&pdens_select=8000&vel=17&theta=45&tdens=2500&tdens_select=0
Thanks for not rounding that off to "nine kilometers" or even "about 10 km" as some less mathematically-inclined contributors would have done. If you've laboriously and precisely calculated that 2009 AV is exactly 7.000 meters in diameter, has a density of 8.000 g/cm3 and will hit the atmosphere at a 45.00 degree angle at exactly 17.00 km/s, why give up that hard-earned precision in your result?
Keeping in mind, of course, that most of the Earth is unpopulated -- in all likelihood the asteroid will strike an ocean (unless a very unlucky ship is hit, nobody would notice this) or a desert/forest (again, someone would have to be very unlucky for this to be noticed). Some of the land impacts may never be discovered -- by the time anyone passes near the impact site, natural forces would probably have erased the crater.
Palm trees and 8
Hmmm... well, I realize that checking a dictionary first would've been a lot of work, but here's what m-w has to say about it. Note that the first entry is for the verb "impact".
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.
What about tsunamis?
Well, other posters have established (well, speculated) that the impact energy would be significantly less than the Hiroshima bomb... there's a link elsewhere in this thread which discusses that a meteorite with a diameter of 10m on impact (meaning significantly larger than 10m when it entered the atmosphere) would have about the explosive force of the Hiroshima bomb.... The number that people are throwing around seems to be around 30-35% of the impact energy, if it hit the ground with a diameter of 7m. I'm going to have to rely on other peoples' calculations, but it does seem to be supported by others.
Let's assume 33%, because the math's easy. The Hiroshima bomb exploded with a peak force of about 18kt, according to Wikipedia. 1/3 of that is 6kt. This is an important number... by any account, it's a big explosion. The largest conventional explosive currently in use in the world is the US-built Massive Ordnance Penetrator (MOP) with a blast yield of 13.6 tonnes... we're talking 400 times more explosive force. If it hit a city with that kind of force, it would do extensive damage.
But let's put this in perspective, and actually answer your question: On May 5, 1954, the US Navy set off Castle Yankee, part of the Operation Castle set of nuclear weapons tests, on the surface of the ocean off Bikini Atoll in Micronesia. The yield of this bomb was 13.5mt, more than 2000x more powerful than this meteorite could possibly be, even assuming that it did not shed any mass at all during entry. Castle Yankee did not cause a tsunami. The likelihood of such a meteorite causing a tsunami is slim to nil.
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?
According to this (I didn't verify any facts) - http://wiki.answers.com/Q/How_much_of_the_Earths_surface_is_inhabited_by_humans
About 1% of the surface is inhabited. So, an impact should directly affect people about once every 500 years. Maybe it's the next time?
None. We were hit by one about 10 meters across on October 8th but no one wants to put the story out for some reason. http://neo.jpl.nasa.gov/news/news165.html
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Asteroid Impact Calculator. Handy thing to have bookmarked, in the event that the astronomers see the next one from far enough off.
It's impossible to be sure what the density and angle of incidence would have been in this case, as this sort of data isn't usually published. It's also impossible to be sure of composition, as that depends on where the asteroid was from. Thus, any results you DO get from the calculator are either meaningless (too much garbage in) or extreme values only.
Having said that, such calculators are fun when they find truly massive craters. The crater under the antarctic ice, for example, is so large that the Earth was unlikely to have ever been hit by something that big in the past 4 billion years. Antarctica is very modern, in comparison.
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Handy thing to have bookmarked
Sounds like a good thing to ping every so often. If the latency goes up or it stops responding altogether then the chances are that a whole load of people somewhere know something that you don't.