What causes the characteristic red glow observed in an emission nebula?

Answer

Recombination of ionized hydrogen (Balmer series)

The red coloration arises because ionized hydrogen, excited by nearby hot, young stars, releases energy as electrons recombine, predominantly resulting in the red hue of the Balmer series.

What causes the characteristic red glow observed in an emission nebula?

#Videos

Nebulae: Crash Course Astronomy #36 - YouTube

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