Nebula

 Nebula  Nebula is an "Interstellar Cloud" of dust, hydrogen, gas and plasma. Before it was known as nebula the general name for any extended astronomical object including galaxies far beyond the milky way (some examples of the older usage survive; for example, the Andromeda Galaxy was referred to as the Andromeda Nebula before galaxies were discovered by Edwin Hubble).Many Nebula form the gravitational collapse of gas in the interstellar medium or ISM. As the material collapses under its own weight massive stars may form in the centre. Most nebulas can be described as a diffuse nebula, which means that they are extended and contain no well-defined boundaries. Planetary Nebula form from the gaseous shells that are ejected from low-mass asymptotic giant branch stars when they transform into White Dwarf. Habitability:

There is no way that you could even step foot onto nebula as it is a cloud of dust. Which will mean that if you try to stand on it you wouldn't be able to.

