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Could these ground based lasers be used for deflecting asteroids?

scrumper 3y ago
I think far less efficiently than propelling a light sail - asteroids being not very reflective. There would be some momentum imparted by the photons impacting and more by ablation of the surface though (if the laser is powerful enough). Enough to deflect? A kiss from a kitten is enough to deflect if you do it far enough in advance…
- SoftTalker 3y ago
  I like the idea of diverting an asteroid by firing kittens at it.
  - jacquesm 3y ago
    Your idea of kissing is a bit violent.
- rokobobo 3y ago
  To divert an asteroid, you’d attempt to ablate a part of it, rather than just rely on its reflectivity: https://en.m.wikipedia.org/wiki/Asteroid_laser_ablation https://en.m.wikipedia.org/wiki/Asteroid_laser_ablation I imagine that tracking an asteroid and continuously pointing the laser array at a specific portion of it, will be harder than tracking a shiny light sail that’s continuously illuminated by the laser array—but as a whole, I think shooting a laser at an asteroid is one of our best bets, so having that array would be a good tool of planetary defense
r00fus 3y ago
Maybe if said asteroid were fitted with a lightsail?
- kurthr 3y ago
  You only lose ~50% using ablation rather than reflection so it would work fine without a lightsail. Long ago there was discussion of using X-Ray lasers pumped with nukes as well. https://www.nytimes.com/1992/07/21/us/star-wars-x-ray-laser-weapon-dies-as-its-final-test-is-canceled.html https://www.nytimes.com/1992/07/21/us/star-wars-x-ray-laser-...
petrocrat 3y ago
Interesting, I was thinking of them for another use as well: dumping surplus photovoltaic/wind collected energy into space as a thermostat of sorts to help control global average temperatures and buy more time to handle CO2 emissions. Not sure but maybe its cheaper than using batteries for time-shifting that energy to reduce fossil fuels during the transitionary period.

I think far less efficiently than propelling a light sail - asteroids being not very reflective. There would be some momentum imparted by the photons impacting and more by ablation of the surface though (if the laser is powerful enough). Enough to deflect? A kiss from a kitten is enough to deflect if you do it far enough in advance…

SoftTalker 3y ago
I like the idea of diverting an asteroid by firing kittens at it.
- jacquesm 3y ago
  Your idea of kissing is a bit violent.
rokobobo 3y ago
To divert an asteroid, you’d attempt to ablate a part of it, rather than just rely on its reflectivity: https://en.m.wikipedia.org/wiki/Asteroid_laser_ablation https://en.m.wikipedia.org/wiki/Asteroid_laser_ablation I imagine that tracking an asteroid and continuously pointing the laser array at a specific portion of it, will be harder than tracking a shiny light sail that’s continuously illuminated by the laser array—but as a whole, I think shooting a laser at an asteroid is one of our best bets, so having that array would be a good tool of planetary defense

r00fus 3y ago

Maybe if said asteroid were fitted with a lightsail?

kurthr 3y ago
You only lose ~50% using ablation rather than reflection so it would work fine without a lightsail. Long ago there was discussion of using X-Ray lasers pumped with nukes as well. https://www.nytimes.com/1992/07/21/us/star-wars-x-ray-laser-weapon-dies-as-its-final-test-is-canceled.html https://www.nytimes.com/1992/07/21/us/star-wars-x-ray-laser-...

petrocrat 3y ago

Interesting, I was thinking of them for another use as well: dumping surplus photovoltaic/wind collected energy into space as a thermostat of sorts to help control global average temperatures and buy more time to handle CO2 emissions. Not sure but maybe its cheaper than using batteries for time-shifting that energy to reduce fossil fuels during the transitionary period.