Question 1

The universe is expanding in such a way suggesting that we live in a matter-dominated universe.

Accepted Answer

The universe is currently thought to be dominated by dark energy, which is causing its accelerated expansion, rather than being matter-dominated.

Question 2

After carefully removing all potential sources of electronic "noise," including bird droppings inside the microwave horn antenna,Penzias and Wilson realized that they were actually detecting radiation from space.

Accepted Answer

This statement accurately describes the discovery made by Penzias and Wilson while attempting to measure cosmic microwave background radiation. They discovered that the persistent "hiss" they were picking up was not due to any local sources of noise, but was in fact a form of radiation that had been predicted by Big Bang theorists.

Question 3

If the universe were found to have a positive curvature,than space would be open rather than closed or flat.

Accepted Answer

A positive curvature implies that the universe is closed and finite, resembling the surface of a sphere, where traveling in a straight line would eventually lead back to the starting point.

Question 4

The era of combination occurred about 3 minutes after the Big Bang,and the era of recombination occurred about 3000 years after the Big Bang.

Accepted Answer

The era of combination actually occurred about 380,000 years after the Big Bang, not 3 minutes. The era of recombination did occur around 300,000 years after the Big Bang, not 3000 years.

Question 5

There is far more helium in the universe than could have been created by hydrogen fusion in stars alone.

Accepted Answer

Helium is also produced in other processes such as alpha decay and the Big Bang itself.

Question 6

Olbers's paradox asks the question,"Is there life elsewhere in the universe?"

Accepted Answer

Olbers's paradox is a question that concerns the nature of the universe and its potential inhabitants, but it does not ask explicitly about the existence of life elsewhere in the universe. Instead, it asks why the night sky is dark if the universe is infinite and filled with an infinite number of stars. This paradox was first proposed by German astronomer Heinrich Wilhelm Olbers in the early 19th century.

Question 7

Temperature variations in the early universe appear as "hot spots" in the cosmic microwave background.The apparent size of these spots depends on the curvature of space.

Accepted Answer

The curvature of space affects the size of the hot spots in the cosmic microwave background.

Question 8

The Andromeda Galaxy has an overall blue shift meaning that it is moving toward the Milky Way Galaxy.

Accepted Answer

The Andromeda Galaxy is moving toward the Milky Way Galaxy, which causes a blue shift in its light spectrum.

Question 9

The universe has been expanding for billions of years.

Accepted Answer

The universe has been expanding since the Big Bang, which occurred approximately 13.8 billion years ago. This expansion continues to this day, as evidenced by various observations such as the redshift of light emitted by distant galaxies.

Question 10

The strong force is one of the four fundamental forces of the universe and it holds protons and neutrons in the nuclei of atoms.

Accepted Answer

The strong force is indeed one of the four fundamental forces and it is responsible for holding together the nucleus of an atom by overcoming the repulsive electromagnetic force between positively charged protons.

Question 11

The Hubble law states that the more distant a galaxy,the less its redshift and the slower it is receding from us.

Accepted Answer

The Hubble law states that the more distant a galaxy, the greater its redshift and the faster it is receding from us.

Question 12

The value of the accepted Hubble constant is about 73 km s^-1 Mpc^-1.

Accepted Answer

This is currently the accepted value of the Hubble constant, based on recent studies and observations.

Question 13

The question,"If the universe is expanding,what is it expanding into?" can easily be answered with observations.

Accepted Answer

The question itself contains a misconception. The universe is not expanding into anything. Rather, it is the fabric of space-time itself that is expanding. Thus, the question does not have a meaning in the context of current scientific understanding.

Question 14

Two prominent research groups came to the same surprising conclusion after taking measurements of the luminosity of Type Ia supernovae at great distances,this being that the universe is accelerating while it expands.

Accepted Answer

This is known as the discovery of dark energy and was a groundbreaking finding in cosmology.

Question 15

Recent satellite missions have confirmed the lumpiness of the cosmic microwave background,which helps explain the current structure of the universe.

Accepted Answer

Recent satellite missions, such as the Planck and WMAP missions, have confirmed the lumpiness or unevenness of the cosmic microwave background radiation, which provides insights into the seeds of galaxy and structure formation in the early universe.

Question 16

The strongest of the fundamental forces of the universe is gravity.

Accepted Answer

The strongest fundamental force is the strong nuclear force, which holds the nuclei of atoms together. Gravity is actually the weakest of the four fundamental forces.

Question 17

The theory of everything (TOE)would provide one equation to describe all of the processes in the universe,and there would be no differences among the gravitational,electromagnetic,and strong and weak nuclear forces.

Accepted Answer

This is the goal of the theory of everything - to unify all four fundamental forces into one equation.

Question 18

Because the universe has continued to expand over the past 13.7 billion years,the radius of our cosmic light horizon is greater than 13.7 billion light-years;the present radius is about 47 billion light-years.

Accepted Answer

The universe has continued to expand since the Big Bang, which means that the radius of our cosmic light horizon has also increased. This means that the present radius of our cosmic light horizon is greater than 13.7 billion light-years, and it is estimated to be about 47 billion light-years.

Question 19

The Big Bang explains why so much helium exists in the universe when it could not have been created by hydrogen fusion in stars alone.

Accepted Answer

The Big Bang theory states that helium was created during the initial moments of the universe through nucleosynthesis, which explains why there is so much helium in the universe today despite not being created solely by hydrogen fusion in stars.

Question 20

The wavelengths of light from very distant galaxies are shifted to the blue part of the spectrum,indicating that the universe is contracting.

Accepted Answer

The opposite is true - the wavelengths of light from very distant galaxies are shifted to the red end of the spectrum, indicating that the universe is expanding. This phenomenon is known as redshift.

Quiz 15: Observing the Evolution of the Universe