Astronomy Quiz # 4
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Created by:
paulmoceyhanton on November 30, 2007
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26 terms
Terms | Definitions |
|---|---|
 Most of the galaxy is made up of... | dark matter |
| are galaxy interactions and collisions common? | yes |
| If two galaxies collide, what is the chance of the stars colliding? | chances are they would not collide |
| variable stars & how they extend the distance ladder | a variable star is a star thats luminosity changes over a short period of time. by measuring the time it takes to pulsate we can determine the distance |
| Why are spiral arms so bright? | Because that is where star formation occurs and the young stars are very bright. |
| Tully-Fisher relation & how it extends the distance ladder | based on redshift and blueshift in the arms of the spiral galaxies, you can judge the luminosity and therefore the distance |
| Which emits more energy, an active galaxy or a normal galaxy? | An active galaxy |
| The four characteristics of life | grow by eating, ability to react to changes in environment, reproduce & pass on genetic material to next generation, capacity for genetic change - evolution |
| Which element are organic molecules based on? | carbon |
| isotropic | the universe looks the same in any direction |
| homogeneous | assumed property of the universe such that the number of galaxies in an imaginary large cube of the universe is the same no matter where in the universe the cube is placed |
| What causes the acceleration in the accelerating universe? | dark energy/cosmological constant |
| Three types of galaxy | ellipticle, spiral, irregular |
| galaxies are found in | clusters and superclusters |
| Huble's Law (V=Ho d) | rate at which a galaxy recedes is directly proportional to its distance from us |
| spectrum of a normal galaxy | looks like a regular blackbody curve |
| spectrum of an active galaxy | does not look like a regular blackbody curve |
| source of energy in active galaxies | supermassive black hole devouring material |
| elliptical galaxies | no cool gas, no new stars, hot interstellar gas |
| irregular galaxies | new stars created, irregular in shape, cool gas, random orbit |
| Gravitational Lensing | light from quasar bending around an object in front of it and making it appear as if there is 2 Quasars |
| spiral galaxy formation | gas & dust clouds & stars combine, formation is slow, fast rotation causes gas clouds to flatten |
| elliptical galaxy formation | star formation fast, slow rotation |
| galaxy cluster | mutual attraction of galaxies |
| synchroton radiation | comes from emission from black hole, because of accretion disc spiraling toward black hole |
| Seyfert Galaxy | Type of active galaxy whose emissions come from a very small region within the nucleus of an otherwise normal looking spiral system |
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