The Formation and Evolution of the Universe

Approximately how many galaxies are estimated to exist in the observable universe?

• 1 billion

• 2 trillion

• 100 million

• 500 billion

What significant discovery did Edwin Hubble make about the universe?

• The universe is contracting

• The universe is expanding

• The universe is static

• The universe is shrinking

What is the Planck length?

• The distance between Earth and the Sun

• The average length of a galaxy

• The smallest possible length in the universe

• The largest possible length in the universe

During the Grand Unification Era, which force first separated from the others?

• Strong nuclear force

• Electromagnetic force

• Gravitational force

• Weak nuclear force

What event is believed to have sparked cosmic inflation?

• The separation of the weak force

• The separation of the strong force

• The separation of the gravitational force

• The separation of the electromagnetic force

What was the primary composition of the universe during the particle era?

• Equal amounts of matter and antimatter

• Only antimatter

• Only energy

• Only matter

What percentage of protons and neutrons were present after the neutron decay process?

• 90% protons; 10% neutrons

• 75% protons; 25% neutrons

• 87% protons; 13% neutrons

• 50% protons; 50% neutrons

At what temperature did the universe allow electrons to orbit nuclei, forming stable atoms?

• 5,000 kelvin

• 1,000 kelvin

• 3,000 kelvin

• 10,000 kelvin

How long after the Big Bang did the first stars begin to form?

• 1 billion years

• 100 million years

• 1 million years

• 10 billion years

What event spreads heavy elements throughout the universe?

• A supernova explosion

• Cosmic inflation

• The formation of the solar system

• The Big Bang