Ice Diamond Riddle SOLUTION ft. Vsauce's Michael Stevens

Layman's guess: Let's assume we don't know if bigger stars are hotter than smaller stars because I honestly can't remember right now. So, you'd need to compare how big the star is vs how bright it is (relative to use here on earth). 

That's not enough information though - is it a super big bright star that's further away or a duller smaller star that's closer by? You'd have to observe them over a period of time as well, have something that tracks the night sky and see if any of them move relative to the rest of the stars. Stars further away will move less than ones closer by - and now you have motion parallax. Given the movements would be super ridiculously relatively small. You'd have to have a computer do all the math and tracking and stuff because who wants to do that for real?

I know you can do it a lot easier with a spectrograph but damn if I know how. I know it wouldn't be redshifting because the expansion due to dark energy is only really a thing that'd work on like... galaxies super far from us? Or how fast something is moving relative to us - like if a galaxy or star is moving closer to us or further away. Or if a star is wobbling because there's something in its orbit... 

And now I'm googling it so I'm just going to disqualify myself.