Ever wonder why your lungs fire up like a star in the night, and how the cosmos might be giving you a secret boost? I have a riddle that might reveal it.

Sure thing, I’ll toss a quick puzzle your way—solve it and the stars will do the rest: I’m not a planet, but I’m in the sky. I can turn a day into night if you let me, but you can’t see me unless I’m gone. What am I?