As you know (or not), the universe is always in a cycle of destruction creation, where, thanks to the dense and strong materials that make up (for example) the earth and we are created.
That is, the stars that make up the galaxies and therefore our universe are in constant creation and destruction, not knowing, at present, no star that comes from the origin “of the times”, at least in the visible universe.
The stars that are created do through the outer layers of others who have been driven out long ago (aeons) and then cast out when they explode for eons later by gravity, others are formed.
This leads that way, at least from about 13 billion years (the age of the universe, believed) without the cooling period and the moments of negative pressure that have made leaps and bounds to become enlarged ago.
So we see nebulae are only ejected by stars in periods prior to “death” or second life material. You know, when they run out of hydrogen, they begin to burn helium, its outer layers can not stand due to internal gravity and are expelled into space, collapsing the star as, in turn, is losing more layers, some with heavier materials They are created by uniting gravity helium atoms and hydrogen into heavier items such as oxygen, carbon, iron, sulfur…
An example of such materials is the nebula that I put in the image, NGC 6523 whose colors are due to have high sulfide concentrations (red) and oxygen (blue). A nebula 100 light years in radius (c’mon relatively large, but get an idea of when a star explodes far as it goes), relatively young (a few million years) and relatively close (about 5500 light-years away).
So bright that you can see with a simple telescope (is located in the constellation Sagittarius) and, with his youth, and is a candidate firm hatchery new stars (dots fat targets are very hot areas where they are concentrating materials to form new stars). Continuing the cycle of life in our universe.
By the way, an eon are a billion years.