ASP Galaxies and Cosmology 2

Question 1

What is dark energy?

Accepted Answer

A hypothetical form of energy driving the accelerated expansion of the universe

Answer

Dark energy is a hypothetical form of energy that permeates all of space and is the leading explanation for the observed accelerating expansion of the universe, comprising about 68% of total energy density.

Question 2

What is the Milky Way galaxy's morphological type?

Accepted Answer

Barred spiral galaxy

Answer

The Milky Way is classified as a barred spiral galaxy (type SBbc), featuring a central bar-shaped structure from which spiral arms emerge.

Question 3

What is the Big Bang theory?

Accepted Answer

A theory that the universe originated from a hot dense state approximately 13.8 billion years ago and has been expanding since

Answer

The Big Bang theory states that the universe began approximately 13.8 billion years ago from an extremely hot, dense state and has been expanding and cooling ever since, supported by CMB radiation and Hubble expansion.

Question 4

What is gravitational lensing?

Accepted Answer

The bending of light around massive objects due to their gravitational field

Answer

Gravitational lensing occurs when a massive object bends the path of light passing near it, as predicted by general relativity, producing magnified, distorted, or multiple images of background objects.

Question 5

What is the observable universe?

Accepted Answer

The spherical region from which light has had time to reach us since the Big Bang, roughly 46 billion light-years in radius

Answer

The observable universe is the spherical region centered on Earth from which light has had time to reach us given the age of the universe (~13.8 Gyr), with a current radius of about 46 billion light-years due to cosmic expansion.

ASP - Astronomical Society of the Pacific Exam Practice Test

ASP - Astronomical Society of the Pacific Exam Practice Test

ASP Galaxies and Cosmology 2