musatov writes "There's talk on The Minor Planet Mailing List about a small asteroid approaching Earth with a 99.8% probability of colliding. The entrance to the Earth's atmosphere will take place October 7 at 0246 UTC (2:35 after this story goes live) over northern Sudan, releasing the energy of about a kiloton of TNT. The asteroid is assumed to be 3-4 meters in size; it is expected to burn up completely in the atmosphere, causing no harm. As a powerful bolide, it may put on quite a show in the sky. For those advanced enough in astronomy to observe, check the MPEC 2008-T50 and MPEC 2008-T64 circulars. NASA's JPL Small Body Database has a 3D orbit view. The story has been already picked up by CNNand NASA."
A very small, few-meter sized asteroid, designated 2008 TC3, was found Monday morning by the Catalina Sky Survey from their observatory near Tucson Arizona. Preliminary orbital computations by the Minor Planet Center suggested an atmospheric entry of this object within a day of discovery. JPL confirmed that an atmospheric impact will very likely occur during early morning twilight over northern Sudan, north-eastern Africa, at 2:46 UT Tuesday morning. The fireball, which could be brilliant, will travel west to east (from azimuth = 281 degrees) at a relative atmospheric impact velocity of 12.8 km/s and arrive at a very low angle (19 degrees) to the local horizon. It is very unlikely that any sizable fragments will survive passage through the Earth's atmosphere.
Objects of this size would be expected to enter the Earth's atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.
Objects of this size would be expected to enter the Earth's atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.
This detail got left out of the story summary, making this sound like a bigger deal than it actually is. This is a routine, mundane event — only the prediction is newsworthy.
This detail got left out of the story summary, making this sound like a bigger deal than it actually is. This is a routine, mundane event — only the prediction is newsworthy.
What this really means is that the new surveys are looking at more of the sky more frequently and deeper (seeing fainter objects), so now we are starting to catch things hitting the Earth that would have been missed in the past.
I wouldn't say this is a mundane event though, this is going to be bigger than the majority of fireballs that get seen. Yes, every few months, but most are over uninhabited areas and don't get seen. And they are not tracked in advance - so we'll get to see how big a fireball you get for a body whose size we have a rough idea of (a few meters across).
For technical updates, see http://cfa-www.harvard.edu/mpec/RecentMPECs.html
Since it is such a small asteroid we can save some money. We don't need to send an all-star cast to blow it up, we only need to send one celebrity. I suggest Bruce Willis, since we can save even more money not having to worry about the return trip.
a small asteroid approaching Earth with a 99.8% probability of colliding
O-M-G We're all going to die! It's the end of the world! Run! Agh, forget that, you'll just die tired! I'm freaking out! I'm freaking out!
The asteroid is assumed to be 3-4 meters in size...
This has been a test of the emergency end of the world system. Has this been the actual end of the world you would have been given explicit instructions to bend over and kiss your ass good bye.
This concludes this test of the emergency end of the world system.
5% of the meteors are iron. Iron is both denser and darker than the far more common stony meteor which means if the asteroid is made of iron, it'll be bigger than expected because the size estimates are based on the amount of light the asteroid is reflecting. If it's iron, its higher density, combined with its larger size, will improve the odds that some remnants will make earth fall.
If it makes earth fall it'll be by far, the most valuable meteorite ever since it's the first asteroid whose arrival was predicted. It'll literally be money from Heaven for whomever finds a piece.
They become meteors *once* they start to interact with the Earth's atmosphere. Until that time, they are classified as space objects, and the names seem to change dependent upon size and approximate mass.
OK, fair point. I should have referenced meteoroids. But still, aside from a sensational headline, wouldn't this usually be classified as a meteoroid rather than an asteroid?
What... the 'roid will dramatically increase the oxygen content of the planet? (insectoid respiratory systems are terribly inefficient, hence drastically limiting their size)... ok, well that last bit kinda ruined the intended joke... except, I didn't think anyone would get it otherwise... *throws hands up in air in self frustration*... btw, did it hit yet?
"A very small, few-meter sized asteroid, designated 2008 TC3..."
"It is very unlikely that
any sizable fragments will survive passage through the Earth's atmosphere..."
Let's pretend that "few-meter-sized" means 3m in diameter, that the space rock is perfectly spherical and will hit the Earth's surface in one piece.
Mass of asteroid = density*volume = (3000kg/m^3)*(4*pi*(1.5m)^2/3) = 28274.334 kg
(Density data from an eyeball-average of table in http://aa.usno.navy.mil/faq/docs/asteroid_masses [navy.mil])
If it hits the surface at 12800m/s, then:
Kinetic energy =.5*mv^2 = 2316233431638.683 J ~ 2316 gigajoules
1 ton TNT = 4.184GJ (from http://en.wikipedia.org/wiki/Joule [wikipedia.org]), so the meteorite impact is roughly 553.6 tons of TNT.
Caveat emptor: many, many approximations.
It doesn't matter whether it hits the ground in one piece, splits into fragments, or burns up entirely before impact. The energy release is the same; only the location and form of the released energy will vary.
I was assuming that the OP meant 1 kton of energy dissipated as heat into the atmosphere. It's a weird unit of measure to use for anything that isn't a point explosion, though. Still, I wonder how much it takes to noticeably affect anything beyond a temporary light show—the weather, perhaps. Probably more than this meteor has, even with your higher figure, unless it hits the ground.
Meteoroid/meteor: Any of the small solid extraterrestrial bodies that hits the earth's atmosphere
Meteorite: A solid body that has arrived on the Earth or Moon from outer space. It can range in size from microscopic to many tons. Its composition ranges from that of silicate rocks to metallic iron-nickel.
Asteroids: Asteroids, also called minor planets or planetoids, are a class of astronomical objects. The term asteroid is generally used to indicate a diverse group of small celestial bodies.
By recent definition [wikipedia.org] this object should not be classified as an asteroid, but a meteoroid. Meteoroid is what the object is when travelling in space. Meteor is the visual phenomenon that you see as the object enters the Earth's upper atmosphere and frictional heating causes the surface of the object to melt and then form a plasma around the object. Meteorite is the remains of a meteoroid that entered the Earth's atmosphere and reached the ground.
It is entirely possible that this meteoroid -depending on its composition, stony, stony-iron, carbonaceous chondrite, or iron/nickel-iron and its velocity and angle of incidence to the Earth's atmosphere- could reach the ground and form a sizable crater. The accepted figure for crater size is roughly 25 times the diameter of the object at the time of impact with the surface. The Barringer Crater [wikipedia.org] was formed by an object estimated to be approximately 50 meters across at the time of impact. If this object reaches the ground at one-half of its present estimated size, it could form a crater 35 to 50 meters across. It would be quite the show if one were within a mile or two of the impact.
A kiloton scale impact is a once a month thing. The only interesting thing about this collision is that we detected the object in advance. All the other ones have hit without warning. A 20 kiloton impact is a once a year event. It's only when you get to 10 megaton events that you have to worry about any effects on the ground, (apart from people looking at the bolide being temporarily or permanently blinded).
Firstly the mass of a satellite would not generate enough of a gravity well to nudge any object off a crash course with the earth. Secondly, as the object in question will be travelling at around 12.8km/s (That's just under 8 miles per second if you are American). The sort of gravity needed to change that trajectory considerably would likely cause much much more problems than this little lump of rock could ever cause.
Well, call me a Washin'ton out-cider, don'cha know, betcha', shucks, all I gotta' do is wink and sure, by golly, that asteroid'll collide with Obama fer sure. 'Cause he's a terrist celebrity, by golly, gosh, so dangerous, and I'd like ta' ignore that question and talk 'bout energy.
One thing I've wondered, those small asteroids that hit the earth, say that land and are about the size of my fist, did those burn down to that size from a bigger size, or are there trajectories that it could land mostly without burning up. Like if it goes in at a really steep angle, could a rock the size of a basketball before it enters be about the size of a basketball when it lands, or is that pretty much impossible?
Yes they "burned down". Yes, there are trajectories that let things land without burning up. But they make for lousy shows, since it requires the rock to skim the outer atmosphere just deep enough to slow below escape velocity, and then slowly (over a period of months or years) lose enough more energy that they reenter permanently. If that happens, and if they're metallic, and if they're really extremely spherical (no hot spots other than the obvious one - out front), then maybe they can make it to the ground substantially intact. Odds - well, literally astronomical.
Well it was only two hours by the time I posted that, but truth be told I'm out a microwave right now. I make my popcorn by putting the bag on top of my wireless router and firing up a bittorent.
Is this really news? (Score:4, Insightful)
Small asteroids that burn up in the upper atmosphere are far from uncommon. Why is this suddenly notable?
it's the end of the world and... (Score:5, Funny)
It's Pluto... (Score:5, Funny)
Here's the NASA article (Score:5, Informative)
Small Asteroid Predicted to Cause Brilliant Fireball over Northern Sudan [nasa.gov]
A very small, few-meter sized asteroid, designated 2008 TC3, was found Monday morning by the Catalina Sky Survey from their observatory near Tucson Arizona. Preliminary orbital computations by the Minor Planet Center suggested an atmospheric entry of this object within a day of discovery. JPL confirmed that an atmospheric impact will very likely occur during early morning twilight over northern Sudan, north-eastern Africa, at 2:46 UT Tuesday morning. The fireball, which could be brilliant, will travel west to east (from azimuth = 281 degrees) at a relative atmospheric impact velocity of 12.8 km/s and arrive at a very low angle (19 degrees) to the local horizon. It is very unlikely that any sizable fragments will survive passage through the Earth's atmosphere.
Objects of this size would be expected to enter the Earth's atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.
Re:Here's the NASA article (Score:5, Insightful)
Objects of this size would be expected to enter the Earth's atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.
This detail got left out of the story summary, making this sound like a bigger deal than it actually is. This is a routine, mundane event — only the prediction is newsworthy.
Parent
Re:Here's the NASA article (Score:5, Interesting)
This detail got left out of the story summary, making this sound like a bigger deal than it actually is. This is a routine, mundane event — only the prediction is newsworthy.
What this really means is that the new surveys are looking at more of the sky more frequently and deeper (seeing fainter objects), so now we are starting to catch things hitting the Earth that would have been missed in the past.
I wouldn't say this is a mundane event though, this is going to be bigger than the majority of fireballs that get seen. Yes, every few months, but most are over uninhabited areas and don't get seen. And they are not tracked in advance - so we'll get to see how big a fireball you get for a body whose size we have a rough idea of (a few meters across).
For technical updates, see
http://cfa-www.harvard.edu/mpec/RecentMPECs.html
Parent
Good News Everyone... (Score:5, Funny)
Since it is such a small asteroid we can save some money. We don't need to send an all-star cast to blow it up, we only need to send one celebrity.
I suggest Bruce Willis, since we can save even more money not having to worry about the return trip.
Re:Good News Everyone... (Score:5, Funny)
Please can we send Tom Cruise instead??
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We're all going to die! (Score:5, Funny)
a small asteroid approaching Earth with a 99.8% probability of colliding
O-M-G We're all going to die! It's the end of the world! Run! Agh, forget that, you'll just die tired! I'm freaking out! I'm freaking out!
The asteroid is assumed to be 3-4 meters in size...
This has been a test of the emergency end of the world system. Has this been the actual end of the world you would have been given explicit instructions to bend over and kiss your ass good bye.
This concludes this test of the emergency end of the world system.
1 in 20 chance it'll be bigger than expected (Score:5, Interesting)
5% of the meteors are iron. Iron is both denser and darker than the far more common stony meteor which means if the asteroid is made of iron, it'll be bigger than expected because the size estimates are based on the amount of light the asteroid is reflecting. If it's iron, its higher density, combined with its larger size, will improve the odds that some remnants will make earth fall.
If it makes earth fall it'll be by far, the most valuable meteorite ever since it's the first asteroid whose arrival was predicted. It'll literally be money from Heaven for whomever finds a piece.
Re:Asteroid? Why not meteor? (Score:5, Informative)
They become meteors *once* they start to interact with the Earth's atmosphere. Until that time, they are classified as space objects, and the names seem to change dependent upon size and approximate mass.
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Re:Asteroid? Why not meteor? (Score:4, Informative)
OK, fair point. I should have referenced meteoroids. But still, aside from a sensational headline, wouldn't this usually be classified as a meteoroid rather than an asteroid?
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Re:Asteroid? Why not meteor? (Score:5, Informative)
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Re:Asteroid? Why not meteor? (Score:5, Funny)
So, a Dwarf Asteroid then?
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Re:Asteroid? Why not meteor? (Score:5, Funny)
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Size doesn't matter (Score:5, Funny)
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Re:Asteroid? Why not meteor? (Score:4, Funny)
And an asteroid breaking in two would be two hemorrhoids?
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Re:Asteroid? Why not meteor? (Score:4, Funny)
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Re:Asteroid? Why not meteor? (Score:5, Funny)
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Re:Asteroid? Why not meteor? (Score:4, Insightful)
Without the sensational headline, who would care?
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Re:Asteroid? Why not meteor? (Score:4, Funny)
Then once they've fully entered the atmosphere astronomers refer to them as "Cosmic World Destroyers.".
But only for a short time.
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Re:Asteroid? Why not meteor? (Score:4, Funny)
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Re: (Score:3, Informative)
It's an asteroid until it enters the atmosphere.
Re:Asteroid? Why not meteor? (Score:4, Informative)
It's an asteroid until it enters the atmosphere.
No, if it's less than 10 meters diameter it's only a meteoroid.
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Re:Asteroid? Why not meteor? (Score:4, Funny)
So then, would a big asteroid just be an aster? Or .... never mind.
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Re:Asteroid? Why not meteor? (Score:5, Informative)
Wrong, it's a meteoroid in space, a meteor in the atmosphere, and if any of it makes it to the ground, it's a meteorite.
It's never an asteroid because it's not big enough.
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Re:Asteroid? Why not meteor? (Score:4, Funny)
I stand corrected; had my oids, eors, and ites crossed.
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Re:Asteroid? Why not meteor? (Score:5, Funny)
Asteroid, meteoroid or hemorrhoid; what does it matter? They're all a pain in the ass.
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Re:Asteroid? Why not meteor? (Score:5, Informative)
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Re:Asteroid? Why not meteor? (Score:5, Informative)
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Re: (Score:3, Informative)
Meteoroid/meteor: Any of the small solid extraterrestrial bodies that hits the earth's atmosphere
Meteorite: A solid body that has arrived on the Earth or Moon from outer space. It can range in size from microscopic to many tons. Its composition ranges from that of silicate rocks to metallic iron-nickel.
Asteroids: Asteroids, also called minor planets or planetoids, are a class of astronomical objects. The term asteroid is generally used to indicate a diverse group of small celestial bodies.
Cost! (Score:5, Funny)
Asteroid is free, Meteor is expensive - costs anywhere from 50 to 99 MP to cast, depending on which FF you're playing.
I'd use an Asteroid over Meteor any day.
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Re:Cost! (Score:5, Funny)
I'm playing on the Super Nintendo.
It's called METEO, you insenstive clod!
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Re:Asteroid? Why not meteor? (Score:4, Informative)
It is entirely possible that this meteoroid -depending on its composition, stony, stony-iron, carbonaceous chondrite, or iron/nickel-iron and its velocity and angle of incidence to the Earth's atmosphere- could reach the ground and form a sizable crater. The accepted figure for crater size is roughly 25 times the diameter of the object at the time of impact with the surface. The Barringer Crater [wikipedia.org] was formed by an object estimated to be approximately 50 meters across at the time of impact. If this object reaches the ground at one-half of its present estimated size, it could form a crater 35 to 50 meters across. It would be quite the show if one were within a mile or two of the impact.
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This sort of impact happens once a month. (Score:5, Informative)
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Re:Asteroid? Why not meteor? (Score:5, Funny)
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Re:Oh jeez... (Score:5, Funny)
2 hours gives CERN plenty of time to aim the LHC at the asteroid and obliterate it with a black hole.
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Because the LHC failed... (Score:4, Funny)
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Re: (Score:3, Insightful)
Re:Jesus my chest. (Score:4, Funny)
Don't get me started on the "if I was a god" thing... If I was a god you'd best get sacrificing some virgins and stuffs.
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Re:Jesus my chest. (Score:5, Funny)
The next big one could come any time and kill us all. If it was really the end of the world would they let us know?
I sure that Slashdot would report it at least twice.
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Re:Jesus my chest. (Score:5, Funny)
And at least the first report would come in only a few days after it happened!
Oh wait..
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Re:good (Score:4, Insightful)
More likely they'll think it's a divine sigh that they're doing everything fine.
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Re:Testing tractor beam theory. (Score:4, Informative)
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Re:Bomb Sudan!!! (Score:4, Funny)
And in other news, the asteroid was found to have large amounts of Naquadah in it.
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Re:I hope it hits Barack Obama (Score:5, Funny)
Well, call me a Washin'ton out-cider, don'cha know, betcha', shucks, all I gotta' do is wink and sure, by golly, that asteroid'll collide with Obama fer sure. 'Cause he's a terrist celebrity, by golly, gosh, so dangerous, and I'd like ta' ignore that question and talk 'bout energy.
Sincerely;
Sarah Palin
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Abandon hope all yee who live! (Score:5, Funny)
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Re:Awesome! (Score:5, Informative)
Yes they "burned down". Yes, there are trajectories that let things land without burning up. But they make for lousy shows, since it requires the rock to skim the outer atmosphere just deep enough to slow below escape velocity, and then slowly (over a period of months or years) lose enough more energy that they reenter permanently. If that happens, and if they're metallic, and if they're really extremely spherical (no hot spots other than the obvious one - out front), then maybe they can make it to the ground substantially intact. Odds - well, literally astronomical.
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Re:Scary... (Score:4, Funny)
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Re:Scary... (Score:5, Funny)
Well it was only two hours by the time I posted that, but truth be told I'm out a microwave right now. I make my popcorn by putting the bag on top of my wireless router and firing up a bittorent.
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