[thedoc (OP)]

This month Asteroid 2012 DA14 a 130.000 Ton lump of rock will pass just 24,000 km from Earth.  That’s closer than many satellites...
Read a transcript of the interview by clicking here

or [chapter podcast=1000083 track=13.02.07/Naked_Scientists_Show_13.02.07_1000408.mp3] Listen to it now[/chapter] or [download as MP3]

[Pmb]

The typical assumption is to detonate a nuke next to it such that the pressure of the radiation will exert so much force as to change its velocity a bit. Then if we've done this in enough advance time then we can change its orbital path enough so that it will miss the Earth.

[David Cooper]

The best thing to do is not see them - if someone sees one, it forces a collapse of the wavefunction and makes the path of the asteroid become certain, at which point it may hit us. If we avoid seeing it, it will remain uncertain as to where it is so it can miss us and hit us at the same time, and then we'll continue to exist in a universe where it missed.

[CliffordK]

A lot depends on the size and pre-warning.

Perhaps yesterday's meteorite, estimated at about 10 tons would be considered the maximum "safe" size.  Had there been advanced warning, the people choosing to seek shelter would have been quite safe.  Of course, many people would have been standing at the windows, or outside to see it.

2012_DA₁₄ which missed Earth shortly afterwards was estimated at 190,000 metric tons.  And, while still small by celestial standards, striking Earth would cause much more severe damage. 

If one Nuked the middle of the asteroid, one would create a cloud of debris.  However, each fragment would be put on a significantly different trajectory than the original object.  Depending on when it was blasted, perhaps only a couple of fragments would collide with Earth at close to the original expected time. 

The question would then be how small the fragments would be.  Could one blast it so that no fragment remained greater than 10 tons?

Hitting Earth with the "shotgun effect" would be brutal, but with advanced warning, most people could survive.
 
[Fixed URL - mod]

[Ophiolite]

The best thing to do is not see them - if someone sees one, it forces a collapse of the wavefunction and makes the path of the asteroid become certain, at which point it may hit us. If we avoid seeing it, it will remain uncertain as to where it is so it can miss us and hit us at the same time, and then we'll continue to exist in a universe where it missed.

I like it in theory, but in practice when I've tried to collapse the waveform of a substantial payrise I always wind up in the wrong universe. The same thing could happen here, so I vote for installing solar sails.

[Pmb]

The best thing to do is not see them - if someone sees one, it forces a collapse of the wavefunction and makes the path of the asteroid become certain, at which point it may hit us. If we avoid seeing it, it will remain uncertain as to where it is so it can miss us and hit us at the same time, and then we'll continue to exist in a universe where it missed.

Sorry, but if you're not just joking around then you must not have a very good understanding of quantum mechanics.. You're missing some important facts. For macroscopic ovbjects the uncertainties become certainties. Where there was an absense of trajectories now has the ani                                                                                                                                                                                                                                                               

[CliffordK]

so I vote for installing solar sails.

The solar sail would have to be HUGE to make much difference. 

However, a solar powered plasma engine would be more efficient than the solar sails, and it would be an optimal scenario for the solar plasma engine, with essentially unlimited mass to expel, if you could just get the right energy density.

[evan_au]

A number of those techniques like the nuclear explosion or solar sail rely on evaporating volatile material, forming a diffuse gas jet which would deflect the object. Presumably this would work better on objects with lots of volatiles (like a comet) than one with lots of iron or stone.

Another suggestion is to use something like a shotgun blast, which would create a distributed pressure on the whole asteroid, keeping it largely intact; any bits blown off would be small in size.

I like the idea of preparing a satellite with compartments of black powder (eg graphite) and white powder (eg Titanium dioxide). You could aim it at an asteroid, and while playing orbital catch-up, analyse its shape and rotation. With judicious placement of black and white powder, solar pressure can divert it over several orbits.

The problem with all of these schemes is that they assume you can spot the satellite several orbits before it strikes the Earth. If you only see it on its final approach, you won't be able to rendezvous with it, and so some high-speed flyby with a nuclear weapon may be the only option, and that will not deflect an object greatly if it only has a fraction of an orbit for the deflection to take effect.

Wiki article on the topic: http://en.wikipedia.org/wiki/Asteroid_deflection_strategies

[yor_on]

We can't.

[David Cooper]

The best thing to do is not see them - if someone sees one, it forces a collapse of the wavefunction and makes the path of the asteroid become certain, at which point it may hit us. If we avoid seeing it, it will remain uncertain as to where it is so it can miss us and hit us at the same time, and then we'll continue to exist in a universe where it missed.

Sorry, but if you're not just joking around then you must not have a very good understanding of quantum mechanics.. You're missing some important facts. For macroscopic ovbjects the uncertainties become certainties. Where there was an absense of trajectories now has the ani

The end of your post appears to be missing. But no - it is not clear that macroscopic objects can't be in highly uncertain states, and it's possible that they are forced to take up more certain states when observed by something complex like a mind which cannot sustain the same uncertain state in the course of processing the data. The very act of processing the data may force a simplification of the data (meaning that its state must become more certain) and this may force the real object to simplify too to conform to the certainty of the data.

[CliffordK]

How far could one maintain a high power laser in space?

Could one nudge an asteroid off course with a powerful laser?

What about forcing the ice on a comet to melt, at least reducing the initial kinetic impact of an intact comet.

[Atomic-S]

The end of your post appears to be missing. But no - it is not clear that macroscopic objects can't be in highly uncertain states, and it's possible that they are forced to take up more certain states when observed by something complex like a mind which cannot sustain the same uncertain state in the course of processing the data. The very act of processing the data may force a simplification of the data (meaning that its state must become more certain) and this may force the real object to simplify too to conform to the certainty of the data.

We have to be sure that no one with an IQ over 10 observes it.

[Atomic-S]

Could one nudge an asteroid off course with a powerful laser?

In principle, irradiating one side the asteroid could  vaporize that side, causing jet thrust to redirect its course.

[shane]

We could try catching them with a net an move them off course three space shuttle connected then detached with a net wrapping around  the meteor using side rockets to push the three shuttles apart grabbing the meteor.....( Meteor Exstraction Service )

[shane]

Try catching the asteroids in a net and move them else where with a powerful rockets of some kind