Planetary nebulas exhibit the future of our sun and solar system. But they have little to do with planets and everything to do with stars. This misnomer of a name probably came about when English astronomer William Herschel first observed them in the 1780s and remarked that they looked like planets through his 18th-century optics.

In fact, planetary nebulas herald the death of a star with less than three times the mass of the sun. As such a star runs burns up all its hydrogen fuel, it starts to burn helium in its core, which produces a much hotter fire in its interior. As a result, it starts to expel its outer layers, which typically includes a great deal of hydrogen and oxygen. Ultimately, the star ejects everything in those outer layers at high velocity—from our vantage, a slow-motion cataclysm that leaves behind only the star's core of mostly carbon. A diamond in the sky called a white dwarf star. 

But the heat from that star also ionizes the gas as it expels it, typically forming ring-like structures that are beautiful to us, but terrible to the planets around the star and any inhabitants those planets may harbor. All that's left of what once may have been a complex solar system is a white dwarf no longer generating new energy, but slowly releasing its stored heat until, in the fullness of time, it becomes a dark, cold cinder aimlessly roaming the galaxy.