Space physics

• Life cycle of a star

  A) Gas and dust cloud

  B) Protostar

  C) Main sequence star

  D) Red giant

  E) Red supergiant

  F) White dwarf

  G) Black dwarf

  H) Supernova

  I) Neutron star

  J) Black hole

  
• Nebula - A star forms from massive clouds of dust and gas in space, also known as a nebula. Gravity pulls more dust and gas together to form a protostar
• Protostar - As the mass falls together it gets hot. A star is formed when it is hot enough for the hydrogen nuclei to fuse together to make helium. The fusion process releases energy, which keeps the core of the star hot.
• Main sequence star - During this stable phase in the life of a star, the force of gravity holding the star together is balanced by higher pressure due to the high temperatures. The Sun is at this stable phase in its life.
• Red giant star - When all the hydrogen has been used up in the fusion process, larger nuclei begin to form and the star may expand to become a red giant.
• White dwarf - When all the nuclear reactions are over, a small star like the Sun may begin to contract under the pull of gravity. In this instance, the star becomes a white dwarf which fades and changes colour as it cools.
• Black dwarf - A star that is so dense that it has no hydrogen fuel left to fuse.
• Supernova - A larger star with more mass will go on making nuclear reactions, getting hotter and expanding until it explodes as a supernova.
• Neutron star - Very dense composed of closely-packed neutrons
• Black hole - A region of space where gravity is so strong that nothing, not even light, can escape.