Protogalactic cloud

Definition

A protogalactic cloud is a massive gas cloud that existed in the early universe and is believed to be the precursor to galaxies. These clouds primarily consist of hydrogen and helium.

5 Must Know Facts For Your Next Test

1. Protogalactic clouds are the building blocks from which galaxies form.
2. These clouds mainly contain hydrogen and helium, with very little heavy elements.
3. The collapse of a protogalactic cloud under gravity leads to the formation of stars and eventually a galaxy.
4. Protogalactic clouds can merge or collide, influencing the shape and size of the resulting galaxy.
5. Observations of distant, high-redshift regions provide evidence for the existence of protogalactic clouds in the early universe.

Review Questions

• What are the primary components of a protogalactic cloud?
• How does a protogalactic cloud contribute to galaxy formation?
• Why are observations of high-redshift regions important for understanding protogalactic clouds?

Related terms

Galactic Halo: The spherical region surrounding a galaxy that contains older stars, globular clusters, and dark matter.

Dark Matter: A form of matter that does not emit light but exerts gravitational forces, playing a crucial role in galaxy formation.

Star Formation: The process by which dense regions within molecular clouds collapse to form stars.