space physics

• list the planets in order

  sun mercury Venus earth mars Jupiter Saturn Uranus Neptune Pluto
• example of a natural satellite

  moon
• first stage of the cycle of a star

  cloud of dust and hydrogen gas - nebula

  the force of gravity pulls the dust and gas together to form a protostar
• second


  as the star gets dense temperature rises anymore particles collide with each other
• 3


  when the temperature gets too high hydrogen nuclei undergo nuclear fusion to form helium

  nuclear fusion brings out a huge amounts of energy which keeps the core of the star hot
• the star enters a long stable period why?

  the outward pressure caused by nuclear fusion tries to expand the star balances the forces of gravity pushing inwards
• what is this stage called?

  a main sequence star
• after main sequence star..

  hydrogen begins to run out

  the outward force due to fusion energy is less than the inward force due to gravity

  this causes it to collapse inwards

  temp increase

  helium nuclei fuse together to create heavy elemetns

  star expands to form...
• the star forms


  a red giant,, at some point the red giant stops fusing helium and shrinks into a white dwarf
• then

  white dwarf gradually cools down and it stops releasing ay energy and forms a black dwarf
• starts bigger then the sun

  once run out of hydrogen they expand into a red super giant

  helium nuclei fuse together to make heavier elements

  eventually they explode in a supernova forming elements heavier then iron

  these elements are distributed throughout the universe

  remains can form a neutron star

  or a black hole