Giant molecular clouds

Definition

Giant molecular clouds are vast regions of gas and dust in space, primarily composed of molecular hydrogen. They are the primary sites for star formation within galaxies.

5 Must Know Facts For Your Next Test

1. Giant molecular clouds can span hundreds of light-years across and contain up to a million solar masses of material.
2. These clouds are often found in the spiral arms of galaxies, where they contribute to the ongoing process of star formation.
3. The temperature within giant molecular clouds is typically very low, around 10-20 K, which allows molecules to form.
4. Regions within these clouds can collapse under their own gravity to form new stars, leading to the creation of stellar nurseries.
5. Observations in radio wavelengths are crucial for studying giant molecular clouds because they allow astronomers to detect emissions from molecules like carbon monoxide (CO).

Review Questions

• What is the primary composition of giant molecular clouds?
• In what regions of galaxies are giant molecular clouds most commonly found?
• Why are temperatures within giant molecular clouds typically very low?

Related terms

Nebula: A nebula is a vast cloud of gas and dust in space, often serving as a nursery for new stars.

Protostar: A protostar is an early stage in the formation of a star, formed when regions within a giant molecular cloud collapse under gravity.

Interstellar Medium: The interstellar medium is the matter that exists in the space between stars within a galaxy, consisting mostly of hydrogen and helium gas along with dust particles.