h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

As I understand it, it is extrememely difficult to deflect an object orbiting the sun in such a way that it actually falls into the Sun itself. This is because something orbiting the Sun has a massive amount of angular momentum that must be removed in order for this to happen. For an object of spacecraft size the easiest way to do this is to fire it at Jupiter in such a way that Jupiter's massive gravitation can do the job, for a more massive object, frankly, you're in difficutly.

Having said all that, the chances of nudging an asteroid in such a way that it hits an almost infinitemal point in space (e.g. the Earth) are vanishingly small. 99.9999% of the time, surely it would miss - after all, there is lots of space and not much Earth.

>>99.9999% of the time it would surely miss.

Are you saying that 1 in a million times, it would hit the Earth?

Cripes and there was me thinking I was exaggerating

Well, we don't have the resources to nudge asteroids. Heck, we don't even have the resources to scan the entire sky for incoming asteroids. But not to fear - as many have demonstrated on the Lift Off! thread, it's much more realistic and cost effective to build a moon base, and a mars colony to diversify the species locales.

We do have the resources to nudge asteroids. As I mentioned earlier, it's already been attempted. And we have the resources to scan the whole sky - may soon even have a 2AU interferometer.

>>We do have the resources to nudge asteroids. As I mentioned earlier, it's already been attempted<<

From what I've read, it would take a sustained push for several years to nudge a sizeable rock off course - when did we do that?

We crashed a spaceship into a Halley's comet.

By that definition of nudge, if I aim a laser pointer at a comet, am I nudging it?

A laser aimed at a comet could cause the ice to evaporate, thus causing a force to push it off course. I think I read that somewhere, anyway..

Deep Impact cashed a weight onto comet Tempel 1 in 2005, but that was just intended to shake the dust up a bit - nothing to do with altering its course.

http://www.nasa.gov/mission_pages/deepimpact/mission/index.html

"The impact is not forceful enough to make an appreciable change in the comet's orbital path around the Sun."

cashed? crashed