| A | B |
|---|
| galaxy | a mass of billions of stars clustered together in a group |
| Milky Way | the medium sized spiral galaxy that is our home galaxy |
| spectrum | a band of colors made when white light is broken up |
| expansion redshift | the absorption lines that result in longer (redder) wavelengths from galaxies moving away from each other as space expands |
| big bang | the beginning moment when the universe was very hot and dense, resulting in a tremendous "explosion" |
| background radiation | radiation that is left over from the beginning moments of the universe and is coming from all directions in space |
| spiral galaxy | a galaxy that looks like a whirlpool |
| elliptical galaxy | a galaxy that is shaped like a football |
| irregualr galaxy | a galaxy that has no recognizable shape |
| Sagittarius | the constellation found at the center of our galaxy |
| Absorbed | Some of the light produced by the heated gases of stars is _______________ by the star's atmosphere |
| absorption lines | The light absorbed by a star's atmosphere drops out of its light spectrum, forming dark _________________ |
| blue | When a galaxy is moving toward Earth, the light shining from that galaxy shifts toward the ___________ end of the spectum |
| red | When a galaxy is moving away from Earth, the light shining from that galaxy shifts toward the ______________ end of the spectrum |
| gravity | ____________ has caused matter to collect into clumps, forming stars and galaxies |
| proto Earth | young Earth grown from clumps of particles stuck together |
| oxygen | When plants developed on Earth ___________________became a waste product of photosynthesis |
| nebula | Dust and gas gathered into a _____________ after the big bang |
