Smoke Signals in Space
Wednesday, August 10, 2011 - 10:30
in Astronomy & Space
Planetary nebulae form when some dying stars, having expanded into a red giant phase, expel a shell of gas as they evolve into white dwarfs.
Planetary nebulae form when some dying stars, having expanded into a red giant phase, expel a shell of gas as they evolve into white dwarfs.