Why is the brilliant glowing phase of an emission nebula considered cosmically ephemeral?
Answer
The massive O and B stars that energize them burn out very quickly
The necessary energy source comes from massive O and B stars, which are fuel-hungry and typically exist for only a few million years before evolving or dispersing the surrounding material.
#Videos
How Does Ionization Cause Emission Nebulae To Glow? - YouTube
What Makes An Emission Nebula (HII Region) Glow? - YouTube
Related Questions
What percentage of atoms in an emission nebula is typically hydrogen?Why are emission nebulae frequently referred to as HII regions by astronomers?What stellar spectral types are usually responsible for powering an emission nebula?What specific energy band must photons possess to initiate the ionization of gas in a nebula?What atomic process causes the nebula to actually produce visible light after ionization has occurred?What is the primary cause of the rich, reddish hue observed in most emission nebulae?In contrast, why do reflection nebulae typically appear blue?What is the approximate kinetic temperature of the gas within a typical glowing emission nebula?What phenomenon explains spectral lines observed in nebulae that cannot be reproduced in dense terrestrial labs?Why is the brilliant glowing phase of an emission nebula considered cosmically ephemeral?