Physics » Space


Key Words

The life cycle of a star:

  • Nebula - a cloud of dust and gas. Stars form from Nebulas.
  • Protostar - dust and gas pull together through the force of gravity to form a Protostar.
  • Main sequence star - the force of gravity pulls everything inwards. It's a stable period in a stars life (our sun).
  • Red Giant - the hydrogen begins to run out in a star and it swells.
  • Super Red Giant - a large star's hydrogen begins to run out and it swells.
  • White Dwarf - the hot dense solid core left by small-to-medium-sized stars when they become unstable and ejects its outer layer of dust and gas.
  • Black Dwarf - the White Dwarf cools and no longer emits a significant amount of energy.
  • Supernova - a big star that has exploded due to the fusion and constant expanding and contracting forming elements as heavy as iron in various nuclear reactions.
  • Neutron star - made from an exploding supernova. The outer layers of dust and gas has been thrown into space leaving a very dense core.
  • Black hole -  a super dense point in space that not even light can escape from made from an exploding supernova from a very big star.

The Solar System - all the things that orbit our sun (our closest star):

  • Planets - large objects that orbit the Sun (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune).
  • Dwarf planets - planet like objects that orbit the Sun but smaller than our main 8 planets.
  • Moons - a natural satellite that orbits the planets.
  • Artificial satellites - man made satellites that orbit the Earth.

Satellite - an object that orbits a second, more massive object

Orbit - the path one object in space takes around another.

Gravity - the force that creates orbits.

The Big Bang - the explosion that came from a very dense, very small space which caused space to start expanding and grow.

Red-shift - wavelengths that have shifted into the red end of the spectrum. It shows that the light from distant galaxies are moving away from us.

Dark matter - an unknown substance which holds galaxies together, but does not emit any electromagnetic radiation.


Also see Forces, Atomic Stucture