nebula

So most people have no idea of the differencebetween an emission nebula and a planetary nebula.But these are the things

in the constellation of Orion.It is a nebula:a star-forming region where new stars are being born.

are the freshly synthesized oxygen.So studying supernova remnants, like the Crab Nebula,allowed astronomers to firmly conclude

we can look inside some of those knobs and see the stars that are being born.And in some places, like the Orion Nebula --there was just an image released of the Orion Nebula --

about the discs of stars and gas that we call the spiral galaxies.And here's a beautiful picture of the Andromeda Nebula,which is our closest, largest spiral galaxy to the Milky Way.