... The Gum Nebula . ... In fact, we are only about 450 light-years from the front edge and 1,500 light-years from the back edge of this cosmic cloud of glowing hydrogen gas. ... Sprawling across hundreds of light-years, emission nebula IC 1396, visible on the upper right, mixes glowing cosmic gas and dark dust clouds. ... Where are all of these meteors coming from? ... That is why the last week's meteor shower was known as the Perseids -- the meteors all appear to come from a radiant toward Perseus. ...