Star cluster RCW 108. Photo courtesy of NASA
. Public domain.
- Hydrogen and helium formed shortly after the Big Bang. Heavier elements were created after a few hundred thousand years.
- Stars contain heavy elements such as iron.
- The "Inside-out" theory states that the center of the galaxy formed first, followed by the outer parts.
- The "Outside-in" theory state that the outer parts of the galaxy formed first, with the center created at another time.
- Stars contain mostly hyrogen and helium, but also have iron, carbon and oxygen.
- There are four stages of stars: Protostar, main sequence, red giant/supergiant and white dwarf/black hole.
- The Earth formed with heavy elements inside of it.
- Heavy elements are found within stars today
- Recent evidence shows that there is a lot of matter in the universe that we cannot directly detect. This matter is called dark matter
- The rate of expansion of the universe is increasing. The cause of this increase is unknown; one possible explanation involves a new form of energy called dark energy.
Last modified: Wednesday, 7 September 2011, 4:30 PM