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perturbation comments on 60m Asteroid currently assigned a .022% chance of hitting Earth. - Less Wrong
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Comments (36)
Only if you act on this urge.
Challenge accepted.
(Now all I need to do is to review perturbative orbital dynamics, find a way to launch a spacecraft even though NASA said it would take them two years to do so and it is scheduled to be at closest approach next February, and develop a mechanism for changing the albedo of an asteroid with paint. In space.)
Not directly related, but an easier question: Do we currently have the technology to launch projectiles out of Earth's atmosphere into a path such that, in a year's time or so, the planet smashes into them from the other direction and sustains significant damage?
(Ignoring questions of targeting specific points, just the question of whether it's possible to arrange that without the projectiles falling into the sun or just following us eternally without being struck or getting caught in our gravity well too soon... hmm, if we could somehow put it into an opposite orbit then it could hit us very strongly, but in terms of energy... hmmm. Ah, and in the first place there's the issue that even that probably wouldn't hit with energy comparable to that of a meteor, though I am not an astrophysicist. In any case, definitely not something to do, but (as noted) morbidly fascinating if it turned out to be fairly easy to pull off. Just the mental image of all the 'AUGH' faces... again, not something one would actually want to do. <clears throat>)
Any kinetic energy an object has, it has to get first. If you compare the size of satellites with their respective rocket it looks difficult to make an object of any reasonable mass get any significant speed. You can trick a bit with swing by maneuvers, but as far as I understand no man made object makes any more than a little sound at the atmosphere while entering. You could however poison the planet with a nice substance.
On the other hand it might be possible to use a man made satellite to deflect a bigger object so that it crashes into earth. But please do not try this on your home.
A fair point. <nods> On the subject of pulling vast quantities of energy from nowhere, does any one country currently possess the knowledge and materials to build a bomb that detonated on the surface could {split the Earth like a grape}/{smash the Earth like an egg}/{dramatic verb the Earth like a metaphorical noun}?
And yes, not something to try in practice with an inhabited location. Perhaps a computer model, at most... actually, there's a thought regarding morbid fascination. I wonder what would be necessary to provide a sufficiently-realistic (uninhabited) physical (computer) simulation of a planet's destruction when the user pulled meteors, momentum, explosives et cetera out of nowhere as it pleased. Even subtle things, like fiddling with orbits and watching the eventual collision and consequences... hm. Presumably/Hopefully someone has already thought of this at some point, and created such a thing. <curiously goes looking>
Can we? Probably not, there don't seem to be enough fissiles available: http://www.coarsegra.in/?p=95
There's also scale issues at play - as your bomb gets larger and larger, relatively more of its energy escapes into space and isn't directed into the ground.
The link in question analyzes the possibility of creating a doomsday weapon that could launch a projectile that would destroy all life on another earth sized planet remotely. That is a far more difficult task than just destroying life on the planet the bomb is on. The limiting factor in question is also fission materials to serve as triggers for the primary explosion in each of hundreds of thousands of shaped thermonuclear explosions. The massive numbers of distinct explosions are needed to progressively accelerate the Orion device but for a single explosion the ration of fissile trigger to fusion material need not be the same.
Mind you the Orion weapon is just intended to obliterate all life. That task becomes comparitively trivial when you aren't trying to do it across space via projectile. But if Multipartite literally wants to smash the earth into pieces I suspect he is out of luck for now!
He wants something which would crack the planet's crust; you're not going to get that with widely dispersed efficient-life-killing thermonuclear strikes (leaving aside the obvious question 'what do you do about the vents and spores etc'). To do that, you need a lot of energy, whether it's a kinetic projectile or a fireball & shockwave. A Project Orion kinetic strike would probably be more efficient than a pile of gigaton nukes since each explosion can be smaller and more energy extracted than it.
Where on earth did widely dispersed efficient-life-killing thermonuclear strikes come into it? Multi was considering a bomb (or cluster thereof) at a single location. The closest to 'dispersion' was when you brought Orion into it, with it's chain of bombs spread out over the launch distance.
Or, alternately, it would be overwhelmingly inefficient because the projectile is aimed away from the planet - or at best along the surface of it.
I incidentally dispute your efficiency claim anyway. I'd be willing to bet that if you collect every one of the bombs you were using for your Orion weapon and place them in single location then it would be more capable of slippiting the planet than the projectile would have been. Even if you managed to make it target the earth directly. If necessary you would of course use several years worth of the entire earth's production of steel (and maybe lead, gold and anything else hard or heavy) and use it to cover the bomb and keep the energy around a tad longer.
Why does it need to be aim along the planet? Use orbital mechanics: Send your spacecraft on an orbit such that it hits the planet it launched from at the fast point of a very long elliptical orbit. Or even just at the far side of the current planet's orbit, whatever. It can't be that hard to get an impact at whatever angle you'd prefer with most of the Orion vehicle's energy, launching direction barely seems to matter.
As I already said, the scaling laws mean the larger the bomb, the less efficient it becomes. Piling together 200 bombs just means you get inefficiency and possible fratricide from the explosion themselves or neutron emission. (Looking briefly at my old notes, underwater explosions have an exponent of tonnage raised to 2/3 for the resultant overpressure wave.)
Doubtful. Breaking the earth up is hard. The biggest explosion ever made is this one: http://en.wikipedia.org/wiki/Czar_bomb
You'd probably have to use a more powerful kind of rocket than any that currently exists, like a nuclear rocket, to launch enough mass into space for it to cause "significant damage" upon reentry.