The universe

• White light is a mixture of colours that have different ranges of wavelengths
• When white light passes through a gas of an element before passing through a prism, the spectrum produced will have a pattern of dark lines. These dark lines are called absorption lines
• As each different element will produce a unique pattern of lines, these absorption spectra can be used to identify which elements are produced in a gas.
• As the light passes through, gas atoms in a star's atmosphere absorb specific wavelengths of visible light
• The further away a galaxy is, the greater increase in wavelength
• The wavelength of the lines change due to the space between the galaxy and the earth expanding
• If the expansion was reversed, everything would revert back to a single point
• Cosmological red shift proved that the universe is expanding, but if the big bang model for the origin of the universe is correct, some energy must have been releases during the big bang
• The high energy, short wavelength, gamma rays that were released during the Big Bang have stretched to longer wavelength microwaves as the Universe expanded