P2- 7.4 - the early universe
- Created by: Grace
- Created on: 06-05-13 11:04
View mindmap
- 7.4- The early universe
- most scientists believe that the universe was created by the Big Bang about 13 billion years ago.
- At first the universe was a hot glowing ball of radiation
- In the first feew minuets the nuclei of the lightest elements formed
- As the universe expanded, over millions of years, its tempurature fell. Uncharged atoms were formed
- Before galaxies and stars formed, the universe was a dark patchy cloud of hydrogen and helium.
- eventually dust and gas were pulled together by gravitational attraction to form stars
- The resulting intense heat started off nuclear fusion reactions in stars, so they began to emit visible light and other raditation
- eventually dust and gas were pulled together by gravitational attraction to form stars
- Very large groups of stars are called galaxies.
- Our sun is one of the many billions of stars in the milky way galaxy.
- the universe contains billions of galaxies
- A galaxy is a collection of billions of stars held together by their own gravity .
- Untitled
- most scientists believe that the universe was created by the Big Bang about 13 billion years ago.
Comments
No comments have yet been made