Unit 1: Astronomy Vocab #1

Front

Big Bang Theory

Back

The scientific explanation that the universe began from a single, very hot and dense point and has been expanding ever since.

Front

Universe

Back

All of space, time, matter, and energy that exists.

Front

Galaxy

Back

A large system of stars, gas, and dust held together by gravity (e.g., the Milky Way).

Front

Milky Way

Back

The galaxy that contains our Solar System.

Front

Expansion

Back

The increase in the distance between galaxies over time as the universe grows larger.

Front

Blueshift

Back

The condensing of light waves from distant galaxies, showing they are moving toward us.

Front

Redshift

Back

The stretching of light waves from distant galaxies, showing they are moving away from us.

Front

Cosmic Microwave Background (CMB)

Back

The faint radiation left over from the early universe, evidence of the Big Bang.

Front

Gravity

Back

The force that pulls matter together.

Front

Light Year

Back

The distance light travels in one year (~6 trillion miles), used to measure space distances.