3 ms·

Probably not - but it is easy enough to deflect an asteroid's trajectory to avoid earth. Over astronomical distances simply heating a portion of the asteroid ca

Probably not - but it is easy enough to deflect an asteroid's trajectory to avoid earth. Over astronomical distances simply heating a portion of the asteroid can provide enough thrust to sufficiently avoid a collision.

A2017U1 8y ago
I believe you need enough advance warning and it's actually quite _simple_ as far as these things go. Always surprised how little science there is in this stuff, both detection and diversion it is a real existential threat to humanity given enough time and yet militaries around the world are out there tilting at windmills spending all their cash on outdated bloated acquisition projects to kill each other better in the most peaceful time on Earth.
- sagartewari01 8y ago
  The reason is probably same as the reason toddlers aren't afraid of guns.
throwaway5752 8y ago
Is that easy? To hit the right spot on a 1km target from a n x 10^9 km (presumably from space and lifting the necessary equipment, otherwise include correcting for atmospheric distortion?). Also, wouldn't power / beam dispersion be a big problem?
- chmod775 8y ago
  It should be significantly easier in space thanks to the lack of an atmosphere that would mess with your beam. I tried to figure out just how accurately we are able to point stuff in space and found out the hubble telescope is able to "lock onto a target without deviating more than 7/1000th of an arcsecond, or about the width of a human hair seen at a distance of 1 mile." [1] That's pretty amazing to me. Though I'm not sure if that would be enough, or whether we can be even more accurate. With a laser beam it might also not be a problem if you're just slightly inaccurate, say only hitting your mark 70% of the time as long as you still manage to heat your target spot up sufficiently. [1]: https://www.nasa.gov/mission_pages/hubble/story/index.html https://www.nasa.gov/mission_pages/hubble/story/index.html
  - throwaway5752 8y ago
    I was more interested in the dispersion aspect of it. I'm not a specialist in this area, but I think a good dispersion rates for a high powered laser is in the area of 0.3 mrad regardless of the medium of transmission. And with that dispersion, targeting an object as far as Jupiter (600M km) would mean the beam would be 180,000km wide when it arrived. Since people smarter than me have floated this as a way of deflecting asteroids, I assume there's some kind of way to focus it over those distances? It seems nontrivial though.

A2017U1 8y ago

I believe you need enough advance warning and it's actually quite _simple_ as far as these things go. Always surprised how little science there is in this stuff, both detection and diversion it is a real existential threat to humanity given enough time and yet militaries around the world are out there tilting at windmills spending all their cash on outdated bloated acquisition projects to kill each other better in the most peaceful time on Earth.

sagartewari01 8y ago
The reason is probably same as the reason toddlers aren't afraid of guns.

throwaway5752 8y ago

Is that easy? To hit the right spot on a 1km target from a n x 10^9 km (presumably from space and lifting the necessary equipment, otherwise include correcting for atmospheric distortion?). Also, wouldn't power / beam dispersion be a big problem?

chmod775 8y ago
It should be significantly easier in space thanks to the lack of an atmosphere that would mess with your beam. I tried to figure out just how accurately we are able to point stuff in space and found out the hubble telescope is able to "lock onto a target without deviating more than 7/1000th of an arcsecond, or about the width of a human hair seen at a distance of 1 mile." [1] That's pretty amazing to me. Though I'm not sure if that would be enough, or whether we can be even more accurate. With a laser beam it might also not be a problem if you're just slightly inaccurate, say only hitting your mark 70% of the time as long as you still manage to heat your target spot up sufficiently. [1]: https://www.nasa.gov/mission_pages/hubble/story/index.html https://www.nasa.gov/mission_pages/hubble/story/index.html
- throwaway5752 8y ago
  I was more interested in the dispersion aspect of it. I'm not a specialist in this area, but I think a good dispersion rates for a high powered laser is in the area of 0.3 mrad regardless of the medium of transmission. And with that dispersion, targeting an object as far as Jupiter (600M km) would mean the beam would be 180,000km wide when it arrived. Since people smarter than me have floated this as a way of deflecting asteroids, I assume there's some kind of way to focus it over those distances? It seems nontrivial though.