this post was submitted on 03 Mar 2024
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Space based mirrors for asteroid mining. Bounce a sh*tton of light from the sun around and just melt asteroids. Love that in the Troy Rising series.
Lots of problems getting there irl (need a better way to get out of the gravity well, and light speed lag for command and control would be a real issue) but the idea is just too fun.
That sounds like a great way to accidentally muzzle sweep a thousand international satellites with a billion-kWh laser beam. Not saying it's entirely a bad idea, but having invisible unshielded beams of stupendous energy bouncing all over the solar system sounds like a recipe for a couple accidental meltings. I could just see someone making an adjustment to the next mining target without informing China and whoops, that secret manned satellite you sent up a couple months ago is now slag.
Depends how it's focused. It wouldn't be a straight coherent beam, because that would actually break thermodynamics if you could produce it from sunlight.
Ooh, this is new info. How so?
One way to look at it is loss of information. If you point a (brightness-tolerant) telescope at a lasar beam, you can't see much. Pretty much every beam is the same. If you point it at the sun there's all kinds of interesting features. Another way is to consider that light is a gas made of photons, and you're essentially talking about making every particle spontaneously align, which in a heat engine would obviously be ridiculous. All of these are entropy-negative processes, and a passive mirror or lens is passive and can only do reversible operations.
Another fun fact that comes out of this is that a magnifying glass can never make a spot hotter than the sun. Here's an XKCD what-if that goes into it - and might honestly be where I learned this first.
Yeah they deal with that in the book series. Lots of AI who do space traffic routing space ships around the beams so as not to get fried.
It's also used as a weapon in the books to defend the solar system. Fune books. I read em once a year or so.