W12H123_Ch14-cosmology---rev3d-Ali-IKS_HO

What is Cosmology?

The study of the universe, focusing on its size, age, and fate.

What does the Cosmological Principle state?

The universe is homogenous and isotropic on large scales, implying it has no center or special point.

Define homogeneity in the context of the universe.

All places in the universe look alike and have a similar composition.

Define isotropy in the context of the universe.

All directions in the universe look alike, meaning we see the same things regardless of the direction.

What is the significance of the Cosmic Microwave Background (CMB) radiation?

It shows uniform temperature and provides evidence for the isotropy of the universe.

What is the Olbers Paradox?

The question of why the night sky is dark if the universe is infinite and filled with stars.

How does Hubble's Law explain galaxy movement?

Distant galaxies are receding from us at a speed proportional to their distance.

What does the analogy of expanding raisins in bread illustrate?

It represents how galaxies are carried along as space expands.

What does the 'age of the universe' estimate rely on?

The current rate of expansion and the Hubble constant.

What does the Cosmic Background Radiation tell us about the early universe?

It provides evidence of radiation from the early phase of the universe, detected as blackbody radiation.

What occurs during recombination in the early universe?

Protons and electrons combine to form atoms, allowing photons to travel freely.

What are the implications of dark matter in the universe?

Most matter in the universe is non-baryonic and contributes to gravitational effects not explained by visible matter alone.

What two problems did classical cosmology face?

The flatness problem and the isotropy of the cosmic background.

What is the cosmological constant?

A parameter in Einstein's equations representing dark energy responsible for the universe's accelerated expansion.

What are the observable structures in the universe according to large-scale surveys?

Filaments and walls of galaxy superclusters, as well as vast voids of empty space.