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40 Cards in this Set
- Front
- Back
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Spirals
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20% of all galaxies--lots of dust and gas; most abundant are normal spirals
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Elliptical Galaxies
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80% of all galaxies—most are dwarfs the super large ones eat others
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Irregular
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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 faster
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Hubble's Constant
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50 to 100 km/sec/mpc
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Cepheids
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1 to 100 days –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 principle
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homogeneous and isotropic
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Cosmological red shift
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all bodies are moving away –further the faster
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Cosmological horizon
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how far back can we 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—main reason
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Quasar
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quasi stellar objects –small energetic cores of early galaxies
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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 not 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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normal matter about 10%
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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 clusters of cluster called super clusters
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Critical Density
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matter needed to open or close the universe
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Recollapsing Universe
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high critical density so universe stops expansion and recollapses
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Critical Universe
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flat universe—this what we think it is—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 forever
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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 our 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 –3K now
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Obler’s 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
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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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