61–70 of 274 posts
Moreover, to keep the beam tightly focused on one probe at a time would require an adaptive optics system that compensated for atmospheric turbulence — something astronomers know how to do over a span of 10 meters, the size of a big telescope mirror now, but not over a mile. Would it be easier just to put the lasers on the moon?
https://en.wikipedia.org/wiki/Lunar_soil#Moon_dust_fountains...
Earlier quoted context omitted.
It would be nice if they could use solar wind to decelerate as they approached. I know there's not enough energy there to insert them into an orbit, but they might get time for a few more pictures?
Just flip the battery in the laser around and it will pull instead of pushing.
It would be cool if there was one or more endowments for this sort of thing, to perpetuate the mission(s), similar to how schools have endowments.
Oddly the most practical use for this is as an interstellar weapon. You don't need to solve the problem of communicating back to Earth, you just need a little terminal guidance. If an iPhone weighs 100 g and we use a non-relativistic formula for energy at 1/4c, that is 2.8 x 10^14 joules, a ton of TNT equivalent is about 4.1 x 10^9 joules, so that is a cool 70kT -- The impact velocity would be high enough to break th…
7kT is half of the Hiroshima bomb. Still destructive, especially if you've got a bunch of them.
Sending a swarm of unguided relativistic projectiles across the universe seems profoundly rude.
> a swarm of unguided relativistic projectiles In a sense, this is essentially what the universe is .
So the whole thing should weigh in the order of several grams, yet it should be able to deflect 100GW of incoming radiation near perfectly (otherwise it will instantly vaporize) while maintaining structural integrity under the acceleration of 60,000g for two minutes? And whatever laser sources we're using must track this smartphone-sized object during these two minutes across several million kilometers. Perfectly. (I…
I love these napkin calculations. The relativistic effect shifts the frequency by 22.47% for 0.2c. Given a 445nm laser (the powerful blue ones), that's 545nm when redshifted (green). It's a bit of a jump, but that wavelength is still smack in the "solar atmospheric absorbtion spectrum window" -- you won't lose much of the energy in the atmosphere. Reading this page diagonally [ http://www.edmundoptics.com/resources/a…
We need way better than 99.5%.
So, how is a tiny smartphone-sized probe supposed to transmit data back to Earth from 4.37ly away?
Similar to how the retroreflectors on the moon allow you to bounce a laser off of them and send it directly back to you.
1.) Why in the world does the 'Light / Laser Beamer' need to be physically located on earth? Why not in space?
2.) Is building 'check-points' for both data and power atop the planets not a possibility? (Solar, chemical, etc).
Moreover, to keep the beam tightly focused on one probe at a time would require an adaptive optics system that compensated for atmospheric turbulence — something astronomers know how to do over a span of 10 meters, the size of a big telescope mirror now, but not over a mile. Would it be easier just to put the lasers on the moon?
It might be easier to fire the lasers from the moon, but getting the lasers to the moon would be a huge pain.