Thermoelectric has terrible efficiency, tho. Also, graphene isn’t inexpensive, and actual macroscopic conductivity is much worse than aluminum or copper.

Efficiency may not be much of an issue if you're spinning up a kilometers-wide, microns-thick graphene sheet at a Lagrange point or something.

At the solar flux levels at the point of that probe (light intensity decays by distance squared), efficiency is probably mostly irrelevant. What's the challenge though is how you irradiate all the heat away to provide a large enough temperature delta.

It’d be neat to see a divergent lens made of carbon metamaterial at the aft of the craft. (... or convergent depending on the shape of the craft)

Wow. This actually sounds like a fun weekend project I'd like to try my hand on.

But in a little more serious manner, if anyone is going in this direction i'd love to hear about it.

I mean, sure. Except for the part where we blot out the only star in our solar system.

Can't we siphon the total energy output of some other star? #NIMBY

I mean, you could have the sphere cover everything except the solid angle that subtends the Earth and literally nothing would change (on Earth).

I think that would mean only a dyson hemisphere, since Earth is illumnated by the entire hemisphere of the sun that faces us, due to the sun's sheer size.

To see the kinds of effects this would have on the gas giants would be fascinating. It would probably drastically alter the coriolis banding and spots on Jupiter and Saturn.

Venus would probably be the only other planet affected, and perhaps comet behavior might change. In fact, I wonder if planets would become so cold, that they might produce visible comas as they warm up, when they enter the sun's (now hemispherical) light cone. That's probably the most prominent effect I can see happening.

It could be much more than a hemisphere while still leaving a line of site from the full sun's hemisphere to the Earth.

line of sight

Right, yes, line of sight from one site to another. Oops.

But does it have to totally block it out? What if we left space in between units so that it just dimmed the sun behind it. Hell, maybe it will help reduce global warming so we can just keep on keepin' on. No need to reduce output levels of anything other than the amount of sun we receive.

Plus, it would be fun to screw with societies in other parts of the galaxy that are using their Kepler satellite equivalents. Every time the Earth transits, the light would dip in a way that would lead the observers to think Earth was much larger, thereby much less massive (for the math to work). Great defensive strategy as they would not think our planet was worth pursuing.

You just solved the Fermi paradox ;)

Well, Wolf 359 is only 8 light years away and is cool enough that we could float carbon or tungsten thermal collection devices on the surface...