24.6.0 Evidence for Black Holes

26. Which of the following objects do many astronomers believe is a black hole? a. the nebula in Orion where new stars are seen to form (from dark dust clouds) b. the Crab Nebula c. Cygnus X-1 d. the open cluster called the Pleiades e. Bayonne, New Jersey

c. Cygnus X-1

28. Astronomers have concluded that growing supermassive black holes (which have millions of times the Sun's mass or more) is pretty unlikely at our location in the Milky Way Galaxy. Where do they think is the most likely place in the Milky Way for such a supermassive black hole? a. at the outer edge of the Galaxy's disk, where there is less pull from other stars b. where a neutron star has already formed c. at the center of the Milky Way Galaxy, where matter is more crowded d. at the location astronomers call Cygnus X-1 e. no place in our Galaxy is likely for a really massive black hole

c. at the center of the Milky Way Galaxy, where matter is more crowded

27. When one member of a binary star system is a black hole, and astronomers detect flickering x-rays coming from the system, where are these x-rays usually coming from? a. from inside the black hole event horizon b. from the photosphere of the companion star (the star that is not a black hole) c. from the singularity d. from a disk of material around the black hole (material that has been pulled from the companion star and is falling toward the black hole) e. from a distant galaxy that just happens to lie behind the black hole system (astronomers discovered that such x-rays have nothing to do with the black hole)

d. from a disk of material around the black hole (material that has been pulled from the companion star and is falling toward the black hole)

25. Far away from a black hole (at the distance of another star), which of the following is a possible way to detect it? a. notice what a large amount of star light it blocks from behind it b. look for the pulsed radio waves it gives off as it rotates like a lighthouse c. look for the neutrinos that escape from the event horizon d. search for flickering x-rays being given off from an accretion disk around the black hole, as it "eats" part of a neighbor star e. you can't fool me, you can never, ever detect a black hole!

d. search for flickering x-rays being given off from an accretion disk around the black hole, as it "eats" part of a neighbor star