| A | B |
|---|
| Doppler Effect | change in wavelength of radiation |
| Electromagnetic Spectrum | forms of energy that travel at 300,000 km/sec |
| Optical telescope | uses a large lens to gather rays of light |
| Reflecting Telescope | uses one concave lens as its objective |
| Refracting Telescope | uses convex lens as objective |
| Schmidt Telescope | uses reflecting mirror and refracting lens |
| Spectroscope | Instrument that disperses a beam into a spectrum |
| Visible spectrum | band of visible colors |
| Big Bang | theory that universe was created out of hydrogen |
| Nebulae | large clouds of dust and gas in space |
| Neutron star | Dense core that remains after a large star explodes |
| Nova | Star that flares into intense brightness |
| Black hole | Massive objects in space that even light rays cannot escape |
| Constellation | group of stars |
| Galaxy | Group of millions or billions of stars held together by gravity |
| Light Year | About 9.5 trillion kilometers |
| Protostar | Large glowing cloud that eventually becomes a star |
| Pulsar | Emits sound and light rays very rapidly |
| Quasar | Radio sources that resemble stars |
| Dwarf star | Stars w/ absolute magnitude of +1 or less |
| Red giant | large red stars that are cooler and more luminous that blue stars |
| Supergiant | 100x as luminous as red giant |
| Variable star | Change in brightness |
| Magnitude | How bright a star is |
| Astronomical unit | Average distance between Earth and sun |
