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Stopping Killer Asteroids
Drog writes "Earth has had a few near misses with asteroids recently (although "near hits" would be more accurate). It's just a matter of time, though, before we detect one with our name on it. In this New York Times article, experts discuss the various ways that we might go about saving our planet. Remarkably, nuclear detonations are not a good option, as they would break the asteroid into many pieces and merely increase our odds of being hit. And a detonation some distance away may simply be absorbed by the asteroid with virtually no effect. Instead, say scientists who study asteroid hazards, a gentle sustained push is what's needed (slow and steady wins the race). Some of the approaches have been discussed in science fiction for years--a mass driver, an electromagnetic machine which hurls dirt from the surface, an orbiting parabolic mirror to heat up the surface and create a plume of vaporized material. All of these methods require one thing, however. Time. At least several decades warning."
Frankly, what really worries me - and what the article really fails to address - is the fact that while there are a few programs going on in the Northern Hemisphere, there's not much happening with our buddies in the Southern Hemisphere - that means half the sky isn't really being covered well.
On another note, who wants to bet that in the event we had, say, 50 years warning, the politicians would be utterly unwilling to do anything about it for at least 48 years?
I'm the stranger...posting to
Nuclear weapons in space act very differently from those in air. To my knowledge, there's never been a detonation in "deep" space: I believe there was a test in low Earth orbit once, but immediately after that the Outer Space treaty was signed (which banned nuclear detonations in space, among other things). The real difference is that a nuclear weapon in space discharges most of its energy in the form of radiation; because there's no air, there's no shockwave. While the radiation would wreak all sorts of havoc with electronic equipment, e.g. satellites, would it cause an asteroid to break up? I'm skeptical. Does anyone know if someone has thought about this question?
People seem to assume that ANY piece that hits the earth will be the end. If you break a moderate-sized asteroid into small pieces, OF COURSE some will hit. And, possibly all the little pieces that hit will burn up in the atmosphere. Of the pieces that do hit, the damage would be MUCH more tolerable.
It all depends on the situation. If something the size of the moon were to suddenly aim itself at the earth, no amount of nukes would help. But a 1km piece of rock travelling at 25km/sec (which would probably poke a nice hole in the Earth's crust and kill us all) could be blown into 1000 pieces, 10% of which would hit the earth and take out a city block if it hit a city, I'll still vote for the nukes.
Then again, maybe it's like choosing between being shot with a big rifle or a shotgun. There's only one way to know for sure...and I'll take a pass, thank you very much.
Chaos, panic, disorder...my work here is done.
The Solution to preventing an asteroidal impact, assuming time is scarce, is a nuclear rocket. The technology for this was already developed way back in the 1960's, and was shut down for obvious reasons. If an asteroid was going to hit us in less than a year without any prior warning, a massive campaign could get a nuclear rocket launched and into space within 6 months. I haven't done the precise astrodynamic calculations, but the factors are - mass of asteroid, time to left to impact, and specific impulse of nuclear rocket. The higher the specific impulse the less time or large the asteroid can be.
Keep in mind that even if the asteroid was only a month away from impact and it was heading our way at 7 miles per second, that means that the asteroid would be 18.1 Millions miles away, which means that the angle of its trajectory would only have to be diverted by less than 1/1000th of a degree. A moderately size nuclear rocket could easily divert an asteroid of 1-2 miles in diameter in plenty of time to divert the disaster.
Planet P - Liberation Through Technology.
www.enthea.org