Term

Earth facts

Definition

It's a medium-sized planet circling a rather average star among billions in the Milky Way Galaxy. Only planet that is known to have life. Third planet from the sun, and it 150 million km away from it.

Term

Big Bang

Definition

Dominant scientific theory about the origin of the universe. The universe was created sometime between 10 billion and 20 billion years ago from a cosmic explosion that hurled matter in all directions. This theory predicts the existence of cosmic background radiation. Widely accepted but can never be proven.

Term

Two facts indicating the Big Bang

Definition

1. Expanding universe - universe galaxies are moving away from one another at tremendous speeds. 2. Pervasive background radiation - 2.7 degrees above absolute zero (-273 degrees celcius) which is heat left over from the Big bang.