Unlike the ultraviolet photons originally emitted by the embedded stars of an emissionnebula, the photons emitted by the recombination of electrons with atoms:

Question

Quizplus · Accepted Answer

Unlike ultraviolet photons, the photons emitted by the recombination of electrons with atoms can travel further and escape the nebula. This is because they have less energy and longer wavelengths, making them less likely to be absorbed or scattered by gas or dust particles. The photons emitted by the recombination of electrons with atoms have less energy than the ultraviolet photons emitted by the stars, so they can escape the nebula and be observed by astronomers.

Unlike the Ultraviolet Photons Originally Emitted by the Embedded Stars