| A | B |
|---|
| Spectroscope | Instrument that breaks up the light from a distant star into its characteristic colors. |
| Spectrum | Band of colors formed when light passes through a prism. |
| Wavelength | The distance from the top of one wave (crest) to the top of the next wave. |
| Red Shift | Shift toward the red end of the spectrum of a star that is moving away from the Earth. |
| Blue Shift | Shft toward the blue end of the spectrum of a star that is moving toward the Earth. |
| Doppler Effect | Apparent change in the wavelength of light that occurs when an object is moving toward or away from Earth. |
| Big Bang Theory | Theory that states that the universe began to expand with the explosion of concentrated matter and has been expanding ever since. |
| Gravity | Forces of attraction between objects. |
| Quasars | Quasi-stellar radio source; distant objects that gives off mainly radio waves and x-rays. |
