[F1grandprix]

Ironically - its actually about the worst thing you can do to deflect an asteroid - its effects are unpredictable.

Most modern proposals call for leaving a large mass near the asteroid - given a few years it will actually change the orbit enough to make it miss Earth.

With present technology - nukes included - we'd need at least 5-10 years warning to stop an incoming asteroid.

The best woudl be something akin to a solar powered engine of some sort. Maybe a drill that would mine from one side, then launch chunks out the other. The chunks would be small enough to burn up if any of them happened to come our way, but otherwise this would be something that would take some time.

A nuke? I would have to check my phusics on this one, but there is not a heck of a lot of mass associated with one of those, so it would not be able to change the course of the center of mass of a large object. I think the only thing you could do would be to use it to split the asteroid up and send its pieces in opposite directions (its center of mass would still be headed for earth, but the two halves, or however many sections, would just go around us....).

Things don't work quite the same way they do in the movies. Not many scriptwriters or directors ever did well in Physics.....

[PilotVertolet]

The best woudl be something akin to a solar powered engine of some sort. Maybe a drill that would mine from one side, then launch chunks out the other. The chunks would be small enough to burn up if any of them happened to come our way, but otherwise this would be something that would take some time.

A nuke? I would have to check my phusics on this one, but there is not a heck of a lot of mass associated with one of those, so it would not be able to change the course of the center of mass of a large object. I think the only thing you could do would be to use it to split the asteroid up and send its pieces in opposite directions (its center of mass would still be headed for earth, but the two halves, or however many sections, would just go around us....).

Things don't work quite the same way they do in the movies. Not many scriptwriters or directors ever did well in Physics.....

Yeah - nukes are pretty - but all you end up with is an asteroid with a hole in it. You need a lot of nukes to make a difference.

Engines might work better - but its expensive, and you need BIG ones to move an asteroid... or little ones running for years on end (ion drives?).

Thats why the "tractor beam" is so cool. The funny thing about gravity, is that putting a little rock near a big asteroid is enough to steer it around the Earth - just a steady little tug that goes on for years.... its like engines - but free.

[Depolit]

Guys, WAY too much tape on your glasses. We already have a proven solution for this....

[AntonioXYZ]

Because asteroids are all different sizes, have different density, and are made of different substances (we know this thanks to space exploration) some methods work better than others, depending on the asteroid. A nuke blown up next to a asteroid that is a loosely bound pile of rubble might make things worse, sending many different sized meteors toward the earth over a wider target. For icy asteroids, one proposal I found interesting is directing concentrated beams of sunlight to a point on its surface. As it heats up, it’ll spew a plume of debris, essentially like a comet, or rocket. Given enough time that might help change its course.

As for NASA's budget, here's what the Planetary Society's position is:

After reviewing the budget, we believe the new plan encouraging government, private, and international partnerships will allow humans to go back to and beyond the Moon faster and more realistically. We also were heartened by the strong support to Earth and space science in the new budget, including the authorization to re-fly the Orbiting Carbon Observatory and the full funding of the robotic Mars program. We will be calling on Members of The Planetary Society to urge Congress to support and appropriate the necessary funds for the new plan.

http://www.planetary.org/blog/article/00002328/