What is an absorption nebula?

An absorption nebula is accurately described as a dust-laden cloud that obstructs the light from objects behind it. These clouds are primarily composed of gas and dust, which absorb and scatter light from stars and other luminous objects located behind them from our viewpoint. As a result, they appear dark against the bright background of the universe.

This phenomenon is significant in the study of astronomy as absorption nebulae often contain the raw materials for star formation and can reveal information about the composition and dynamics of interstellar space. While other types of nebulae, such as emission nebulae, give off light, absorption nebulae are distinguished by their role in blocking light rather than emitting it.

The other choices do not correctly define an absorption nebula; for instance, while some regions where stars are born may indeed contain dust, they are not exclusively designated as absorption nebulae. Star clusters and clouds that emit light in the spectrum also do not fit the definition, thus underscoring the unique characteristics of absorption nebulae.