Given that we actually see a meteor/comet in time to do something about it, the problem then becomes how do we do something about it?
The idea is to have millions/billions of lasers distributed across the planet, when the offending meteor is spotted point them all at it. Given enough power it should instantly vapourise the surface, exerting pressure onto the meteor which will gradually change it's orbit.
Lasers are currently very cheap due to mass manufacturing all that's then needed is a distributed control system (the internet) and accurate pointing mechanisms. Even if all the lasers aren't quite pointed in exactly the right place a normal distribution could lead to high enough wattage per square meter to vapourise the surface of the meteor if enough lasers are used.-- scubadooper, Jul 20 2004 Apophis http://en.wikipedia.../wiki/99942_Apophis [DrBob, Nov 24 2006] Apophis orbit http://neo.jpl.nasa...i-bin/db?name=99942Requires java. [DrBob, Nov 24 2006] NASA article regarding Apophis http://impact.arc.n...s_detail.cfm?ID=165 [DrBob, Nov 24 2006] B612 Foundation http://www.b612foundation.org/"The Goal of the B612 Foundation is to significantly alter the orbit of an asteroid, in a controlled manner, by 2015." [DrBob, Nov 24 2006] isn't this sort of baked with Reagan's Star Wars programme?-- jonthegeologist, Jul 20 2004 No, that was to put lasers (each individually powerful enough to act alone) in space to defend against ICBMs, this is to distribute a huge number of lasers (each low power and therefore cheap) to act against meteors and if neccesary ICBMs (not that I think that will ever be a serious threat) which could be a good way to get funding-- scubadooper, Jul 20 2004 Probably a good solution to that problem. But wouldn't a huge amount of low power lasers cost as much as a few high power ones ( and occupy much less space around the planet) ? Btw, where would you locate them ? All around the globe ?-- NeoPiter, Jul 20 2004 <edit> Maybe, maybe not, I'd guess not as you'd still have to have a signifcant mumber of high powered lasers and any error in pointing them won't be averaged out, in addition they'd be </edit> less fault tolerant and yes all around the globe-- scubadooper, Jul 20 2004 And would all of them be directed to fire at the same time? Or will they fire only when the Earth's rotation gets to one exact point ?-- NeoPiter, Jul 20 2004 If the laser can 'see' the target it'd fire-- scubadooper, Jul 20 2004 This would be handy come Year 2036. a little known fact is that the small asteroid named Apophis is aimed in a collision course with earth on this date...it will pass by us in 2027 in a visible orbit if there are any budding astronomers among us.....NASA has undertaken planning to divert it's orbit, but your idea sounds a lot simpler than their manned craft plan.......-- Half-life below 40yrs, Nov 23 2006 got a linky, half? that sounds interesting.-- Custardguts, Nov 24 2006 If we put all those annoying laser pointers together, it may be powerful enough to hit a meteor. :) One of the big problems is finding all those objects that's in earth's path. Space is vast & we have to find & excamine millions of things out there. the lasers don't have to be powerful enough to push the OPEC (Object in Path of Earth Collision) it could burn one point on the surface. the vapors would act like a rocket & push it out of harm's way.-- the great unknown, Jan 09 2007 random, halfbakery