Universe and Gravity

Front

What is the Doppler effect when light is moving away from an observer?

Back

Red shift.

Front

What does it mean that the universe is expanding?

Back

The amount of space between galaxies is increasing.

Front

What force keeps a planet in orbit around the sun?

Back

Gravity.

Front

What theory explains the origin of the universe as a rapid expansion from a small point?

Back

Big Bang Theory.

Front

What happened during the Big Bang?

Back

All of what would become the universe was concentrated in a single small point, or singularity, which rapidly expanded into what is now stars, planets, galaxies, matter, and energy.

Front

What is gravity?

Back

A force that attracts two bodies towards each other, keeping planets in orbit around stars.

Front

What is the significance of red shift in astronomy?

Back

It indicates that an object is moving away from the observer, helping to measure the speed of galaxies.

Front

What is the observable universe?

Back

The part of the universe that we can see and measure, limited by the speed of light.

Front

What is a galaxy?

Back

A massive system of stars, stellar remnants, interstellar gas, dust, and dark matter bound together by gravity.

Front

What is dark matter?

Back

A form of matter that does not emit light or energy, making it invisible and detectable only through its gravitational effects.