Molecular clouds

Definition

Molecular clouds are dense regions of gas and dust in interstellar space where molecules, particularly hydrogen, can form. They are crucial sites for star formation as they provide the raw material needed to create new stars.

5 Must Know Facts For Your Next Test

1. Molecular clouds are primarily composed of molecular hydrogen (H2) and helium.
2. These clouds can span dozens to hundreds of light-years across and contain up to a million solar masses of material.
3. The temperature within molecular clouds is typically very low, around 10-20 Kelvin.
4. Molecular clouds often contain denser regions called 'clumps' or 'cores,' where star formation is initiated.
5. The presence of molecules such as CO (carbon monoxide) helps astronomers map and study these clouds using radio telescopes.

Review Questions

• What are the primary components of molecular clouds?
• Why are molecular clouds important for star formation?
• What is the typical temperature range within a molecular cloud?

Related terms

Interstellar Medium (ISM): The matter that exists in the space between stars, consisting of gas and dust.

Protostar:

A young star still in the process of forming from a collapsing cloud of gas and dust.

Nebula:

A general term for a cloud of gas and dust in space, which can be an active region for star formation or remnants of dead stars.