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Asteroid Flies Under the Radar, Literally
mrn121 writes "Space.com is reporting that a 16-foot wide asteriod has passed the Earth in a phenomenally close call. The Asteroid, named 2004 YD5, passed just below the 22,300 mile range where geostationary satellites sit. What makes the incident most interesting is that the asteriod was not seen until after it passed the Earth, due to the well-known Cosmic Blind Spot caused by the Sun."
NASA's Deep Impact is going to impact a comet to study the composition of it. If sucessful the impact will create a crater on the surface. It has little to do with breaking up asteroids.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"According to the article, "the object, now named 2002 EM7, was probably between 40 and 80 meters (130-260 feet) in diameter" and was capable of flattening a whole city.
Pedantic Man to the rescue!
You meant meteoroid, not meteor. A meteoroid is a solid body, moving in space (not in atmosphere), that is smaller than an asteroid and larger than a speck of dust. It becomes a meteor when it enters a planetary atmosphere (and meteoroids almost invariably burn up on atmospheric entry).
Pedantic Man, away!
Just to correct something...
Asteroid:
Any of numerous small celestial bodies that revolve around the sun, with orbits lying chiefly between Mars and Jupiter and characteristic diameters between a few and several hundred kilometers. Also called minor planet, planetoid.
I.E. still in space and orbiting.
Meteor:
A bright trail or streak that appears in the sky when a meteoroid is heated to incandescence by friction with the earth's atmosphere. Also called falling star, meteor burst, shooting star.
I.E. that which is shooting through the atmosphere, heating it and itself up in the process due to friction.
Meteoroid:
A solid body, moving in space, that is smaller than an asteroid and at least as large as a speck of dust.
I.E. still in space, not necessarily orbiting, smaller than an Asteroid. I think you meant this one.
Meteorite:
A stony or metallic mass of matter that has fallen to the earth's surface from outer space.
I.E. Fallen onto the Earth. It's what you may find if you're either lucky, or very observant.
So just to conclude.. this is indeed a Meteoroid, as it's not big enough to actually be an Asteroid. But it's more fun to say, and less confusing to the masses - especially the Nintendo owners out there.
Yeah. A couple years ago, I ran across an article that contained a graph of object size versus frequency of entering the Earth's atmosphere. The 1-per-day frequency was for objects of about 3 meters diameter.
;-)
Several objects of this thing's size enter our atmosphere each week. Most of them disintegrate in the atmostphere. A few have pieces that hit the ground, though they're usually rather small by the time they (or the pieces) hit.
To do serious damage, we'll need a rock at least a few hundred meters across. Of course, one of those may hit us next week. Or 10,000 years from now. (Or both.
I wonder if I could find that graph again?
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Despite what Hollywood would have you believe, ICBM's aren't designed to be launched into space and they have neither the thrust to propel a warhead out of our gravity well, nor the accuracy to hit anything smaller than 50km wide even if they did (and that's assuming that the asteroid is close). ICBM's were designed for one purpose...to put a small warhead within a few hundred yards of a stationary target less than 15,000 km away from the launch point. They are useless against moving targets hundreds of thousands of km away.
There is nothing else we could throw at an incoming asteroid. The simple reality is that if we humans spotted a big rock coming at us, even with a month or two to prepare for it, all we could really do is dig a shelter, store food away, and pray that it comes down on the OTHER side of the planet.
There is nothing so pathetic as seeing a beautiful young theory roughed up by a tough gang of facts.
it could have taken out a satellite by chance
The chances of something that large hitting a given satellite is probably only a bit more than it hitting you. It is a bit more because it may burn up by the time it reaches the ground. There are 5+ billion people and probably only around 2000 active satellites. Assuming such a rock has about a 50/50 chance of making it to the ground without vaporizing, then it is far more likely to hit a person than a satellite.
(5,000,000,000 * 0.5 * 0.5) / 2000 = 62,500
(The second 0.5 is because most sats are bigger than people.)
Thus a person is about 60,000 more times likely to get hit by a rock that size than a satellite.
Now small rocks are another story. Those pose a far bigger danger to satellites. We on the surface are protected by our atmosphere against pebble- and baseball-sized space rocks. But satellites are not, and those things rip through them like bullets.
Table-ized A.I.
your link is defunct, the correct link is http://www.time.com/time/reports/v21/science/aster oid.html
OK, I am totally guessing here and I'm sure I'm so far wrong it is funny, but I'll still say it anyway.... You point out that there wouldn't be any atmosphere. So, much less shockwave, since there isn't much there to carry it. However, the physical energy released by the bomb must go somewhere. Would it not be *more* focused on the asteroid, since it is the most available medium? Please don't flame me too bad for this wild speculation :)
Geek used to be a four letter word. Now it's a six-figure one.
the red state ghettos are only in the blue dominated areas within the state. High poverty and high crime rate? It will vote Democratic.
If you compress a gas, the temperature of the gas increases, When you expand a gas, the temperature of the gas decreases (which is why those compressed air cans get cold when you use them). Quite a bit of the heat generated by a meteor is caused by the compression of the atmosphere as the meteor enters the atmosphere. As the atmosphere re-expands behind the meteor, it cools back down; but the meteor is in a constant hot-spot.
Friction does play a part. Heat is created as the potential energy of the meteor is converted to kinetic energy (due to acceleration as it loses speed with respect to the atmosphere).
Microsoft is to software what Budweiser is to beer.
0.000195 of a centimeter.
"A language that doesn't affect the way you think about programming, is not worth knowing" - Alan Perlis
As others have pointed out the chances for that hapening are very remote, but anyway, here's an interesting graphic showing the 2004 YD5's position when passing compared to all Low Earth, GPS, and geosynchronous sats. As the page says, it passed 1.88 earth radii from the orbit of GPS satellite BIIA-19.
To really do any good, one would drive the warhead into the asteroid before detonation
No, that would just break it up and make it worse. Some fragments might be accelerated sideways enough to miss the earth, but more will be accelerated forward or backward along the asteroid's current path. The result would be like being hit by shotgun blasts as the earth rotated through the asteroid fragments.
The total energy imparted to the planet by the asteroid would remain the same, but it would be spread over a greater area.
A better idea would be to use a stand-off blast where the nuke is detonated alongside the asteroid to give it a sideways shove and deflect it whole, but even this would be extremely inefficient, and you'd need to identify the trajectories very early.
NB, to the grandparent poster, the fact that the asteroid is the only object in the vicinity of the explosion would have no affect on the amount of energy it receives.
"I've got more toys than Teruhisa Kitahara."
It's known by people who work in the field. There are several other blind spots in astronomy, though:
1) the moon (although the moon itself is only ~0.5" across, telescopes need to stay far away from it...
2) the earth (jokingly for earth-based stuff, serious for space telescopes)
3) the galactic plane (unless of course you're looking at stuff in the galactic plane...)
4) andromeda (it's friggin huge!)
Quid festinatio swallonis est aetherfuga inonusti?
Africus aut Europaeus?
There were two asteroids. The link labeled 'blind spot' was a link to an earlier, larger one. The link actually labelled '16 foot asteroid' described the smaller one.
Both discuss the 'blind spot'
There's a good chance that most, if not all of them will be too small to survive and even if some hit, it will be a number of small smacks, not one big WHAM
I think the problems will be caused by energy being imparted to the earth by millions of tonnes of rock at high velocities rather than the impacts with the ground.
What do you think the result of flash-heating the upper atmosphere to several thousand degrees for several hours is likely to be?
"I've got more toys than Teruhisa Kitahara."
Actually the old Nike Zeus/Spartan antiballistic missle from the late 60s early 70s might have the range and speed. But it is unlikly that it chould it hit far enough away to make a big difference.
Probably not.
The Zeus EX/Spartan had an operating ceiling of only 560 km (350 mi) and maximum range of 740 km (460 mi). I've read that the ideal range to intercept an asteroid/comet, so that its trajectory is altered enough to guarantee a complete miss, is 300 million km (186 million mi). That's because such an object would be travelling very quickly (as much as 60,000+ km/h) and we'd need a lot of lead time (at least a week) to figure out the object's composition and course, and prepare a missile/payload that could alter its course (or destroy it).
In other words, I don't think that anti-missile technology from the 1950s (or even present-day technology, for that matter) is going to save us.
D.
The giant radio astronomy dish in Arecibo has been used in the past for radar mapping Venus, basically zapping a giant radio signal to see what was under the cloud cover. Also, while this is more similar to terrestial techniques, the Magellan spacecraft that went to Venus and kinda made the Arecibo bounces obsolete mapped the planet using radar. Many of the regular Mars orbiters carry radar mapping equipment, to the point where we often know more about the topography on Mars than Earth (with its oceans).
And heating due to rapid motion is different from friction how?
Yay, a question I know the answer to! (I'm a fluid dynamicist). The difference is that friction is a fundamentally irreversible process--it removes free energy from the system, whereas (essentially adiabatic) compression is a reversible process. Free energy could, in principle, be extracted from the compressed/heated gas in front of the asteroid.
Mathematically, friction enters the equations through a viscosity term, which removes energy; compression enters through pressure and momentum (and temperature, through an equation of state). The terms are separate.
To do serious damage, we'll need a rock at least a few hundred meters across.
It depends on what you call "serious damage". The Tunguska event blasted thousands of square kilometers of Siberian forest and it is estimated that it was a meteor just 60 meters wide.
A similar impactor hitting a populated area would decimate a whole metropolis or even a small US state. I would call that "serious damage".