We often find dark nebulae associated with bright H II regions.

Question

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Dark nebulae are dense interstellar clouds of gas and dust that can block the light of background stars. H II regions, on the other hand, are regions of ionized hydrogen gas that emit light due to the presence of hot, massive stars. These regions are often associated with young star-forming regions, which may also contain dark nebulae. The ionizing radiation from the bright H II region can cause the surrounding dust and gas to heat up and glow, making the dark nebulae more visible. Therefore, it is common to find dark nebulae associated with bright H II regions. Dark nebulae are often found in close proximity to bright H II regions because the ionizing radiation from the nearby H II region causes the gas and dust in the dark nebula to become excited and emit light, revealing the otherwise invisible structure.

We Often Find Dark Nebulae Associated with Bright H II