What are the main gases found in a nebula?

Nebulae are vast clouds of gas and dust in space, primarily composed of hydrogen, which is the most abundant element in the universe. In addition to hydrogen, helium is the second most prevalent gas found in nebulae, existing in smaller quantities. This composition is critical in the formation of stars and planetary systems, as the gravitational collapse of these gases can lead to the creation of new celestial bodies.

Other gases, such as oxygen, nitrogen, carbon dioxide, and methane, may exist in trace amounts or be produced within the nebulae due to various chemical processes, but they do not constitute the primary components. The fundamental structure and evolution of nebulae hinge on the presence of hydrogen and helium, making them essential for understanding cosmic processes such as star formation and the lifecycle of matter in the universe.