Stars and the Universe

• 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...
  

• 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.
  

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
  

stellar nebula ---> creates a...

average star ---> expands to become...

red giant ---> cools down and forms...

planetary nebula --->

white dwarf

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