nuclear fusion – The process in which lighter atomic nuclei join together to make heavier atomic nuclei and a massive amount of energy is released.
red giant – The huge red star formed when a star expands and shines less brightly as it starts to die.
l red shift – A shift in the wavelength of light towards the red end of the spectrum. It occurs when the light source is moving away from the observer and is evidence for an expanding Universe.
supernova – The huge explosion that occurs when a massive red giant is at the end of its life. white dwarf – The core that remains after the outer layers of a small red giant drift away.
black hole – An object whose gravitational pull is so strong that nothing can escape, not even light. It is formed after a really massive star collapses in a supernova.
l comet – A lump of rock and ice, which has a very elliptical orbit around the Sun.
Doppler effect – The shift in frequency of a sound wave or an electromagnetic wave due to the relative movement of the source or observer.
galaxy – A vast collection of millions of stars.
lnebula – A massive cloud of gas and dust in which a star is formed.
lneutron star – The very dense core that remains after a massive red giant collapses in a supernova