5 Foundations of Cosmology Free Online FlashCards

What does cosmology study?

Cosmology is the scientific study of the universe as a whole, including its contents, large-scale structure, history, and evolution.

What key change did the heliocentric model introduce?

The heliocentric model shifted Earth from the center of the planetary system, challenging earlier models that placed a stationary Earth at the center.

What relationship did Hubble present evidence for in 1929?

Hubble presented evidence that more distant galaxies generally recede faster than nearer ones, helping overturn the idea of a static cosmos.

What does the Big Bang theory describe?

The Big Bang describes space itself expanding from an early hot, dense state; it is not matter exploding from one point into pre-existing empty space.

What is the observable universe?

It is the region from which light or other signals have had time to reach us since the early universe became transparent. It is not necessarily the entire universe.

Why is the observable universe wider than its age in light-years?

The universe is about 13.8 billion years old, while the observable universe is about 93 billion light-years across. Space expanded as the oldest light traveled.

What does a light-year measure?

A light-year is a measure of distance: the distance light travels in one year.

What causes cosmological redshift?

Cosmological redshift occurs when the expansion of space stretches light from distant galaxies toward longer, redder wavelengths.

What is the cosmic microwave background?

The CMB is cooled remnant light from the early universe, released when the universe had cooled enough for atoms to form and light to travel freely.

What do distant Type Ia supernovae reveal about expansion?

Type Ia supernova observations showed that the universe’s expansion is accelerating today. Dark energy is the name for the unknown cause of this acceleration.

What observations provide evidence for dark matter?

Dark matter is inferred from gravitational effects such as the motions of stars and galaxies and the bending of light by gravitational lensing.

How do dark matter and dark energy differ?

Dark matter acts gravitationally like matter and helps explain cosmic structure. Dark energy is associated with the universe’s accelerated expansion.