There’s a 250 light-year hole in the center of emission…

There’s a 250 light-year hole in the center of emission nebula N44 and astronomers aren’t sure why. It could be that particle winds from massive stars are pushing out the gas. Perhaps a more compelling explanation though, based on the detection of X-ray emitting gas, is that supernova explosions carved out this cavern!

(Image Credit: Gemini Obs., AURA, NSF | via Apod.gov)