The beginning of the universe

What does the Big Bang theory propose?

• The universe was always the same size.

• The universe expanded from a hot, dense state.

• The universe was formed from the collision of two galaxies.

What is thought to have been created at the time of the Big Bang?

• Only stars and galaxies

• Space, time, and matter

• Only light and gravity

What observation provides strong evidence that the universe is expanding?

• Blue-shift of distant galaxies

• Red-shift of distant galaxies

• The constant speed of galaxies

The greater the red-shift in a galaxy’s light, the:

• Faster it is moving toward us

• Further away it is

• Slower it is rotating

What did scientists detect in 1965 that supports the Big Bang theory?

• Radio waves from stars

• Gamma rays from black holes

• Microwaves from all directions

What is the cosmic microwave background radiation (CMBR)?

• Radiation from nearby stars

• Remnant energy from the early universe

• Light from the sun scattered by space dust

Why does the CMBR support the Big Bang theory?

• It is the oldest known type of radiation in space

• It is concentrated in a few areas

• It is constantly changing direction

What would happen if the density of the universe is greater than a certain critical value?

• The universe would expand forever

• The universe would remain the same size

• The universe would eventually collapse in a Big Crunch

If the density of the universe is too low, what will eventually happen?

• The universe will expand forever

• Galaxies will collide

• Stars will form more rapidly

What is the main reason scientists believe dark matter exists?

• It can be seen through telescopes

• Its gravity affects the movement of stars

• It emits large amounts of light