A nebula is a distinct luminescent part of interstellar medium, which can consist
of ionized, neutral, or molecular hydrogen and also cosmic dust. Nebulae are often
star-forming regions, such as in the Pillars of Creation in the Eagle Nebula.
In these regions, the formations of gas, dust, and other materials "clump" together
to form denser regions, which attract further matter and eventually become
dense enough to form stars. The remaining material is then thought to form
planets and other planetary system objects.
(wikipedia])[whttps://en.wikipedia.org/wiki/Nebula