The star cluster Omega Centauri, which is about 16,000 light-years from Earth.
Photo courtesy of Goddard Photo and Video Blog. CC BY.

Blueshift: shift in absorption bands towards the blue (short wavelength) end of the spectrum. Occurs when light moves towards the observer

Cosmic Microwave Background Radiation: radiation left over from the creation of the universe

Doppler Effect: change in wavelength caused by motion

Electromagnetic Spectrum: collection of all radiation, visible and invisible

shift in absorption bands towards the red end of the spectrum (long wavelength). Occurs when light moves away from the observer

Scientific Notation: way to express very large or very small numbers

Spectrum: range of colors in the rainbow
Last modified: Wednesday, 7 September 2011, 4:26 PM