Astro Test #2 June 2018

The Milky Way
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Terms in this set (50)
Galaxy A is half as far from us as Galaxy B. The recession speed of Galaxy A is _______ the recession speed of Galaxy B½ as large asThe largest elliptical galaxies appear to be the result ofGalaxy collisionsSpace between galaxies is expanding, which means that light from a galaxy that is moving away from us has its wavelengthIncreased compared to what it normally would beA Seyfert galaxyIs a spiral galaxy with an intensity that varies on a timescale of minutesA galaxy is 2 million light-years away. The light from the galaxy that you observe now was emitted2 million years agoSc galaxies appearBlueAbout __________ of spiral galaxies are barred spirals2/3In the 1930s, Fritz Zwicky observed that galaxies in the Coma cluster move too fast to be explained by the visible matter in the galaxy cluster. This was the first evidence forDark matterThe super-massive black hole at the centre of the Milky Way galaxy contains __________ of the galaxy's massA tiny fraction of 1%The relationship between the distance of a galaxy from us and its recession speed was discovered byEdwin HubbleGravitational lensing is theBending of light from very distant galaxies by more nearby galaxiesGravitational lensing was first proposed by ________ and first confirmed by the observations of ________Einstein/ EddingtonGravitational lensing is one of the main ways to collect evidence forDark matterCosmic background radiation was first observed in _______ by _______1964, Robert Wilson and Arno PenziasCosmic background radiationProvides strong evidence for the Big Bang theoryThe reciprocal of the _______ give an approximate value for the age of the universeHubble constantThe parameter Ω indicates the fate of the universe. If Ω = 1, then the universe willContinue to expand indefinitely, but the expansion rate approaches zero more and more closely as time passesThe parameter Ω indicates the fate of the universe. If Ω > 1, then the universe willExpand for a while, but slow down, reverse, and eventually collapse in a "Big Crunch."The parameter Ω indicates the fate of the universe. If Ω < 1, then the universe willContinue to expand indefinitely, but the expansion rate is approximately constantThe best current measurements of the parameter Ω are that its value isApproximately equal to 1Ordinary stars typically emitVery little of their energy as radio wavesQuasars appear star-like, but emitAn enormous amount of radio wavesRich galaxy clusters consist mostly ofElliptical galaxiesObservations of elliptical galaxies with multiple nuclei is evidence forGalaxy MergersRadio galaxies are typically certain elliptical galaxies that emit large amounts of radio waves from theirCores and "radio lobes" that are outside their visible regionsThe size of the universe is[This is not currently known.]A typical quasar emitsMuch more power than an entire galaxy.Right after the Big Bang, the universe wasVery hot and dense, and it expanded and gradually cooledDuring the evolution of the early universe, when protons combined with free electrons, the universeBecame transparent to lightThe cosmic background radiation currently has its peak in the part of the electromagnetic spectrumMicrowaveThe age of the universe is currently thought to be about14,000,000,000 years oldThe currently accepted resolution of Olbers paradox is that[None of the others.]The idea that the universe is expanding was first proposed by based on his or her observationsEdwin HubbleThe Higgs boson was first detectedBy the LHC in 2012Helium was first produced in the universeIn the first few minutes after the Big BangThe universe has approximately the same average properties in all directions; to de- scribe this fact, we say that the universe isIsotropicLight from distant stars has its path bent by the gravitational effect of matter between us and the source of the light. This is a prediction ofEinstein's theory of general relativityData from the WMAP and Planck satellite observatories suggest that the universeIs flat (overall), has accelerating expansion, will probably expand foreverIn the first minute or so after the Big Bang, atomic nuclei could not exist becauseIt was too hotIt is currently estimated that the content of the universe is approximately5% ordinary matter, 25% dark matter, and 70% dark energy