Our Universe- Introduction- the easy bit!
- The earth part of a series of planets orbiting around the sun. This we call the solar system.
- Our solar system is part of huge collection of stars and orbiting materisl in a galaxy called the milky way.
- There are billions of galaxies in the universe...
How Stars Are Formed
- Clouds of dust and gas are pulled together by the attractive force of gravity between them
- As they get more compressed, their temperature rises
- Eventually it rises enough to fuse together hydrogen gas into helium- the begining of nuclear fussion.
- This fusion continues, and a star is formed. All stars use nuclear fusion as an energy source, and all of the elements found naturally in our universe come about through this process.
- Debris and dust rotating around the star may clump together to form planets.
How Does A Star Remain Stable?
2 forces balance to create stability during the life cycle of star:
- Gravity pulling the star inwards
- Radiation pressure- the effect of huge temperatures- within the star act outwards
Life Cycle of Smaller Stars
stellar nebula ---> creates a...
average star ---> expands to become...
red giant ---> cools down and forms...
planetary nebula --->
Life Cycle of Larger Stars (greater mass)
Stellar nebula---> creates a...
Massive star ---> expands into a...
red supergiant ---> shrinks rapidly, explodes into...
Supernova ---> turns into either....
- If a medium star: neutron star
- If a large star: black hole