Question 1

The cosmic microwave background is&#10;A) the result of radioactive decay of elements produced in supernovae explosions.&#10;B) scattering of microwaves by dust particles.&#10;C) electromagnetic waves from cold hydrogen gas.&#10;D) radiation resulting from the beginning of the universe.

Accepted Answer

The cosmic microwave background (CMB) is radiation that is a remnant from the early universe, specifically from a time about 380,000 years after the Big Bang when the universe cooled enough for electrons and protons to combine into neutral atoms, allowing photons to travel freely. This makes the CMB a snapshot of the oldest light in the universe, providing critical information about its early stages and the overall structure of the cosmos.

Question 2

His question made a paradox of why the universe is not infinite in all aspects:&#10;A) Newton&#10;B) Einstein&#10;C) Hubble&#10;D) Obler

Accepted Answer

The paradox related to the question of why the universe is not infinite in all aspects is known as Olbers' Paradox, named after Heinrich Wilhelm Olbers. It questions why, if the universe is infinite and filled with stars, the night sky is not completely bright with the light of those stars.

Question 3

The universe has matter evenly distributed; this principle is called _____.&#10;A) homogeneous&#10;B) isotropic&#10;C) Hubble time&#10;D) Hubble constant

Accepted Answer

The principle that matter is evenly distributed throughout the universe is known as homogeneity.

Question 4

The maximum distance that light can travel during the age of the universe is called ______.&#10;A) cosmic region&#10;B) cosmic horizon&#10;C) cosmic dimensions&#10;D) Hubble horizon

Accepted Answer

The maximum distance that light can travel during the age of the universe is referred to as the cosmic horizon. This concept is fundamental in cosmology, as it defines the boundary of the observable universe, beyond which we cannot see due to the finite speed of light and the finite age of the universe.

Question 5

When photons had their last interactions with the big bang gas is the ___________________.

Accepted Answer

The answer of When photons had their last interactions with...

Question 6

The remnant of the beginning of the universe is called the _______.

Accepted Answer

The answer of The remnant of the beginning of the...

Question 7

Dark matter began clumping even before the last scattering epoch.

Accepted Answer

Dark matter, not interacting with light, began to clump due to gravitational attraction even before the last scattering epoch, which is when photons decoupled from matter, allowing the universe to become transparent.

Question 8

The CMB is about 3K.

Accepted Answer

The Cosmic Microwave Background (CMB) is indeed about 3 Kelvin, indicating the residual thermal radiation from the early universe.

Deck 81: The Edges of the Universe