Quiz 9 Astro 201 Fall 2010 Prof Bechtold Correct answers in BOLD 1 We can study galaxy formation and evolution because A light travels at a finite speed B most matter is dark C the Universe is expanding D we have telescopes outfitted with camcorders and have made movies E we know nothing about how galaxies form 2 A galaxy which has a lot of star formation going on in its center because of a recent merger with another galaxy is called a A starburst galaxy B milky way galaxy C Good and Plenty galaxy D dwarf galaxy E elliptical galaxy 3 Halton Arp is an astronomer who made the first big catalog of A quasars B dwarf galaxies C gravitational lenses D merging and interacting galaxies E normal spiral galaxies 4 The Hubble deep field was used to look at distant galaxies One thing that was found was that A distant galaxies are much bigger than nearby ones B distant galaxies are irregular collections of small clumps of stars and gas C distant galaxies have no dark matter D distant galaxies are not forming stars E distant galaxies are all ellipticals 5 We think galaxies formed by the progressive gravitational collapse and merger of small clumps into bigger structures This process is A imaginary B hierarchical C fragmentary D tidal E quasi stellar 6 A supermassive black hole in the center of a galaxy which is accreting gas and stars is called a A quasar B dwarf spheroidal galaxy C X ray binary star D brown dwarf E gravitational lens 7 When a relativistic electron orbits a magnetic field line radiation is emitted in a process called A synchrotron emission B bremsstrahlung emission C thermal emission D polar emission E Rayleigh scattering 8 If the average density of the Universe is less than the critical density the Universe will a b c d e expand forever eventually collapse eventually stop expanding accelerate none of the above 9 Astronomers say that they have observed black holes directly even though by definition a black hole is an object from which light cannot escape This is because a Astronomers have dark matter telescopes b The Hubble Space telescope has an infrared camera c Gas which is falling into a black hole forms a hot accretion disk d Black holes emit Hawking radiation e Astronomers have sent spacecraft to black holes and watched them disappear 10 Which of the following best summarizes what we mean by dark energy a Matter which has been sucked into black holes b Matter which has been sucked into black holes c Matter which has been ejected by black holes via the Hawking Process d It is the name given to whatever is responsible for causing the expansion of the Universe to accelerate with time e Matter that we know is there because we see its gravitational effect but which we cannot see