4 ms·

A meteorite would be hypersonic when first entering the atomsphere and then supersonic the rest of the way until maybe a few hundred meters before impact. Besid

by eksith 14y ago

A meteorite would be hypersonic when first entering the atomsphere and then supersonic the rest of the way until maybe a few hundred meters before impact. Besides that, if it's not a solid iron-nickle meteorite, it may even breakup or explode well above the surface instead of staying intact. It's not quite like taking out a satellite in low Earth orbit in that there's plenty of information on its orbit, trajectory, tumbling characteristics, approximate mass etc... It would be very, very, very hard to intercept a meteorite without a lot of information before it even got close to Earth. The report of a missile salvo taking it out is very suspect IMO. Without more information, it's hard to tell.

jandrewrogers 14y ago
I don't know about "taking it out" per se but an air defense system designed to hit ballistic missiles in the terminal phase could also hit an inbound meteorite. It is within the performance envelope of those types of systems. That said, against a meteorite it won't do much good since it is an inert mass. It is plausible that the Russians launched an interceptor just to be safe. If it is a meteor, it neither hurts nor helps. If it is a man-made structure, it will do some real damage to it. Either way they can always argue "better safe than sorry".
- eksith 14y ago
  Russians have scientists working on the meteorite problem, but I doubt the military would do a hail Mary launch on this. If anything, they would much rather let it fall intact than risk having it break up and spread damage to a much larger area. But that still assumes they can respond quickly enough or had missiles on standby with weapons that can affect a meteorite (not specifically ballistic reentry capsules, but actual meteorites). There's a worrying thought. It may be hot enough for infrared seekers, but it's no jet. Jets are fragile by comparison so, unless they had purely kinetic weapons... but that's still speculation at this point. We still don't know what the Russians did or if they did anything at all. I doubt they even knew this specific meteor would enter the atmosphere. It's already hard enough detecting much bigger rocks in Earth-crossing orbits.
  - jandrewrogers 14y ago
    It does seem silly to intercept. The computers could ascertain that the trajectory was unlikely to have originated on Earth in milliseconds. Modern terminal guidance systems are all imaging based. Or at least the US ones have been for a couple decades; I imagine the Russians are using something at least vaguely similar. Basically, the missiles latch onto the target visually and are capable of recognizing their target from the details of its appearance (in an air defense context, not just "an airplane" but "that specific airplane"). It is why, contra Hollywood, modern terminal guidance systems are nigh impossible to spoof. The missile knows what the airplane looks like and can read the tail number off your craft, so as long as it can locate it (even if it temporarily loses sight), it is likely to hit unless the motor runs out of gas. Heat has little to do with it, though the imagers often work in broad spectrum infrared. Lots of smaller, impacters with kiloton-class impact energies are never discovered or discovered at the very last minute. This looks like a pretty small rock in terms of damage done so it could easily have been missed by sky surveys.
  - estel 14y ago
    If they had the time to go through the chain of command and reach a measured, rational decision, perhaps; but it's quite possible that a crew manning a missile defence platform had only a few seconds to decide on a course of action, and went with "better safe than sorry" without considering whether it even was something that could break up.
- DeepDuh 14y ago
  Looking at these videos it doesn't look like there has been a defense missile: http://www.youtube.com/watch?v=1wUqmS35REY http://www.youtube.com/watch?v=1wUqmS35REY. Such missiles would leave a visible trail in the atmosphere, wouldn't they?
  - eksith 14y ago
    If you're referring to the beginning, that actually looks like it was the trail left behind by an aircraft much earlier. I live near an airport, so I see these quite often after jets go by. Usually that type of contrail appears after 2-5 minutes after a jet flies by. Far too late to intercept a meteorite which can reach the surface in minutes-seconds. If you mean the middle, that's most definitely the aftermath of the meteorite itself. You can see this in the other videos.
    - DeepDuh 14y ago
      Yes, that's what I meant: I couldn't see a missile trail either, only airplane trails and the one from the meteorite itself.
- cmsmith 14y ago
  >It is within the performance envelope of those types of systems. Is this true? Reentry speed of an ICBM is something like 5 km/s. Entry speed of a meteor is a minimum of 11 km/s, and more like 25 km/s if this object wasn't in an Earth-like orbit to begin with. Missile interceptors travel much slower than either, and they have a tough time hitting ICBMs from what I understand.
  - varjag 14y ago
    Also, Russian missile interceptors are outfitted with nuclear warheads, to address the precision problem. And virtually all Russian missile defense is concentrated around Moscow. So it's safe to conclude the military was not involved here.
    - n3rdy 14y ago
      The meteor must have exploded 20 miles high, wouldn't a nuclear warhead cause an EMP at that altitude? Or would a lower yield lack that?

by eksith 14y ago

jandrewrogers 14y ago

I don't know about "taking it out" per se but an air defense system designed to hit ballistic missiles in the terminal phase could also hit an inbound meteorite. It is within the performance envelope of those types of systems. That said, against a meteorite it won't do much good since it is an inert mass. It is plausible that the Russians launched an interceptor just to be safe. If it is a meteor, it neither hurts nor helps. If it is a man-made structure, it will do some real damage to it. Either way they can always argue "better safe than sorry".

eksith 14y ago
Russians have scientists working on the meteorite problem, but I doubt the military would do a hail Mary launch on this. If anything, they would much rather let it fall intact than risk having it break up and spread damage to a much larger area. But that still assumes they can respond quickly enough or had missiles on standby with weapons that can affect a meteorite (not specifically ballistic reentry capsules, but actual meteorites). There's a worrying thought. It may be hot enough for infrared seekers, but it's no jet. Jets are fragile by comparison so, unless they had purely kinetic weapons... but that's still speculation at this point. We still don't know what the Russians did or if they did anything at all. I doubt they even knew this specific meteor would enter the atmosphere. It's already hard enough detecting much bigger rocks in Earth-crossing orbits.
- jandrewrogers 14y ago
  It does seem silly to intercept. The computers could ascertain that the trajectory was unlikely to have originated on Earth in milliseconds. Modern terminal guidance systems are all imaging based. Or at least the US ones have been for a couple decades; I imagine the Russians are using something at least vaguely similar. Basically, the missiles latch onto the target visually and are capable of recognizing their target from the details of its appearance (in an air defense context, not just "an airplane" but "that specific airplane"). It is why, contra Hollywood, modern terminal guidance systems are nigh impossible to spoof. The missile knows what the airplane looks like and can read the tail number off your craft, so as long as it can locate it (even if it temporarily loses sight), it is likely to hit unless the motor runs out of gas. Heat has little to do with it, though the imagers often work in broad spectrum infrared. Lots of smaller, impacters with kiloton-class impact energies are never discovered or discovered at the very last minute. This looks like a pretty small rock in terms of damage done so it could easily have been missed by sky surveys.
- estel 14y ago
  If they had the time to go through the chain of command and reach a measured, rational decision, perhaps; but it's quite possible that a crew manning a missile defence platform had only a few seconds to decide on a course of action, and went with "better safe than sorry" without considering whether it even was something that could break up.
DeepDuh 14y ago
Looking at these videos it doesn't look like there has been a defense missile: http://www.youtube.com/watch?v=1wUqmS35REY http://www.youtube.com/watch?v=1wUqmS35REY. Such missiles would leave a visible trail in the atmosphere, wouldn't they?
- eksith 14y ago
  If you're referring to the beginning, that actually looks like it was the trail left behind by an aircraft much earlier. I live near an airport, so I see these quite often after jets go by. Usually that type of contrail appears after 2-5 minutes after a jet flies by. Far too late to intercept a meteorite which can reach the surface in minutes-seconds. If you mean the middle, that's most definitely the aftermath of the meteorite itself. You can see this in the other videos.
  - DeepDuh 14y ago
    Yes, that's what I meant: I couldn't see a missile trail either, only airplane trails and the one from the meteorite itself.
cmsmith 14y ago
>It is within the performance envelope of those types of systems. Is this true? Reentry speed of an ICBM is something like 5 km/s. Entry speed of a meteor is a minimum of 11 km/s, and more like 25 km/s if this object wasn't in an Earth-like orbit to begin with. Missile interceptors travel much slower than either, and they have a tough time hitting ICBMs from what I understand.
- varjag 14y ago
  Also, Russian missile interceptors are outfitted with nuclear warheads, to address the precision problem. And virtually all Russian missile defense is concentrated around Moscow. So it's safe to conclude the military was not involved here.
  - n3rdy 14y ago
    The meteor must have exploded 20 miles high, wouldn't a nuclear warhead cause an EMP at that altitude? Or would a lower yield lack that?