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41 Cards in this Set
- Front
- Back
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what are spirals?
what is the most common type? |
- 20% of all galaxies, mostly dust and gas
- Normal spirals are most abundant |
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Elliptical galaxies?
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80% of all galaxies, most are dwarfs, the super large ones "eat" or consume others
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Irregular galaxies-
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No shape, near collisions or collisions made them, our satellite galaxies are the Magellan clouds and are irregular
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standard candles
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each type of galaxy has certain absolute magnitude
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clusters
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galaxies are not alone but in clusters
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super cluster
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clustering of clusters
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Hubble's Law
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the farther the distance, the greater the speed
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Hubble's Constant
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50-100 km/sec/mpc
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Cepheids
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1 to 100 days -only yardsticks to other galaxies
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Period Luminosity
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how we use Cepheid's to measure distance
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Cosmological principe
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homogeneous and isotropic
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cosmological red shift
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all bodies are moving away, the further they get the faster
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cosmological horizon
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how far back we can see
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look back time
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time since the beginning of the universe
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radio galaxies
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colliding galaxies are the main reason behind their formation
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quasar-quasar stellar objects
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small energetic cores of early galaxies
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dark matter
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90% of the universe
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dark energy
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makes up 60% of dark matter
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rotational curve
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stars do slow down as they go around the galaxy because of dark matter
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orbits in clusters
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galaxies orbit each other faster because of dark matter
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Gravitational lensing
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light is bent by galaxies more than it should because of dark matter
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MACHOs
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massive compact halo objects-may be dark matter
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Baryonic matter
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is composed of normal matter about 10 percent only
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WIMPS
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weakly interacting particles- may be dark matter
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large scale structures
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clusters of galaxies and super clusters
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critical density
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matter needed to open or close anything in the universe
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recollapsing universe
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high critical density so universe stops expansion and re-collapses
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critical universe
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flat universe- this is what we think it is, dont know, barely expanding
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coasting universe
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expands forever
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accelerating universe
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expansion goes faster
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Matter
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that which dominates the baryonic materials in our universe
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antimatter
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opposite to matter
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big bang
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universe expands out rapidly
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Gut
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grand unification of all forces
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Inflation
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time at beginning that universe expanded quickly
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Cosmic microwave background
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left over of early hot universe
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Oblers paradox
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why is night sky dark? - cannot have infinite size and infinite number of stars
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natural selection
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darwin proposed survival of the fittestq
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mutation
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biology changes life
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habitable zone
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area around a star that life can exist
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drake equation
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probabilities of life that communicates in universe
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