Black Hole silhouetted against the Milky Way Fall 2009 ASTR 2030 Homepage

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 clicker Fall 2009 ASTR 2030 Black Holes: Clicker Questions

    Tue 2009 Aug 25 (not graded):

  1. A black hole is:
    A. A collapsed star.
    B. A quasar.
    C. An object whose gravity is so strong that not even light can escape.
    D. A region of spacetime where space is falling faster than light.
    E. A mathematical object predicted by general relativity, which does not exist in reality.

  2. The event horizon of a black hole is:
    A. The physical (gaseous/liquid/solid) surface of a black hole.
    B. The surface from within which light cannot escape.
    C. A place where you will be torn apart by tidal forces.
    D. A place where the spacetime curvature becomes infinite.
    E. A place where space and time as we know them come to an end.
    F. The entrance to a wormhole, which will transport you to another place and time.

  3. The singularity of a black hole is:
    A. The physical (gaseous/liquid/solid) surface of a black hole.
    B. The surface from within which light cannot escape.
    C. A place where you will be torn apart by tidal forces.
    D. A place where the spacetime curvature becomes infinite.
    E. A place where space and time as we know them come to an end.
    F. The entrance to a wormhole, which will transport you to another place and time.

    Th 2009 Aug 27 (not graded):

  4. For what kinds of black holes do astronomers see evidence?
    A. Exploding mini-black holes.
    B. Stellar-sized black holes.
    C. Supermassive black holes at the centers of galaxies.
    D. The Universe as a whole is a black hole.
    E. Astronomers do not observe black holes at all.

  5. Why does the spaceship not go any closer to Hades?
    A. Because the black hole would pull the spaceship inside the event horizon.
    B. Because there are no closer orbits.
    C. Because it would take too much rocket fuel to go closer.
    D. Because the x-rays would kill a human.
    E. Because the tidal forces would tear a human apart.

  6. How long does Thorne say that our journey to the center of the Milky Way, 30,000 lightyears distant, will take, from our point of view? We accelerate at one gee (one Earth gravity) for the first half of the journey, then decelerate at one gee for the second half.
    A. Almost no time.
    B. 20 years.
    C. 30,000 years.
    D. 60,000 years.
    E. Much longer than any of the above.

  7. Will the probe fall into the black hole?
    A. Yes.
    B. No.

    Tue 2009 Sep 1:

  8. The tidal force is the difference in the gravitational force between two parts of an object (e.g. between your head and your toes). The tidal force of a black hole will tear you apart:
    A. at the event horizon;
    B. somewhere inside the event horizon;
    C. at the singularity;
    D. inside the event horizon if the black hole has a stellar-size mass, or outside the horizon if the black hole is supermassive;
    E. outside the event horizon if the black hole has a stellar-size mass, or inside the horizon if the black hole is supermassive.

  9. If the postulates of special relativity are correct, would the light have moved differently if Cerulean, not Vermilion, had emitted the light?
    A. Yes.
    B. No.

  10. On this spacetime diagram, how fast is Cerulean moving relative to Vermilion, in units of the speed of light?
    A. 0 .
    B. 1/2 .
    C. 1 .
    D. 2 .
    E. The information on the diagram is insufficient to answer the question.

    Th 2009 Sep 3:

  11. What does this spacetime diagram represent (choose the best answer)?
    A. Shows that time is a kind of spatial dimension.
    B. Demonstrates that light travels at the same speed in any inertial frame.
    C. Cerulean travels at 1/2 the speed of light relative to absolute space.
    D. Cerulean sends out light beams in opposite directions, they reflect off mirrors, and return to him at the same instant.
    E. Cerulean can travel forward or backwards in time, just as he can travel forwards or backwards in space.

  12. How is it possible that Vermilion and Cerulean can both think each other's clock runs slow?
    A. Because light travels at the same speed in any inertial frame.
    B. Because of time dilation.
    C. In special relativity, reality depends on the observer, and it is possible for two logically inconsistent things to occur.
    D. Because their clocks run at different rates.
    E. Because their notions of simultaneity differ.

  13. According to Thorne, what influence did the Michelson-Morley (1887) experiment have on Einstein's thinking?
    A. Michelson and Morley's failure to detect any difference in the speed of light in different directions suggested to Einstein that the speed of light is a universal constant;
    B. Michelson and Morley's failure to detect the motion of the Earth through the aether suggested to Einstein that there is no aether, no absolute space or time;
    C. It provoked Einstein to think about Maxwell's equations of electromagnetism, which showed that light is electromagnetic waves;
    D. Very little.

    T 2009 Sep 8:

  14. Not graded: Do you understand time dilation?
    A. I think so!
    B. I understand the diagram we filled in last week, but not much more.
    C. I think I could maybe understand if I thought more about it.
    D. I have no clue.

  15. Not graded: Do you understand Lorentz contraction?
    A. I think so!
    B. I understand the diagram we filled in last week, but not much more.
    C. I think I could maybe understand if I thought more about it.
    D. I have no clue.

  16. Which of the following is an inertial frame?
    A. A frame that carries inertia.
    B. A frame with respect to which unaccelerated objects move in straight lines at constant velocity.
    C. A rotating frame.
    D. An accelerating frame.
    E. The frame in which you are sitting right now.

  17. If Earth time is 4 years, then the traveler's time is:
    A. 4 years;
    B. less than 4 years;
    C. more than 4 years.

  18. On your way out to Alpha Cen, you appear to me, watching you through a telescope on Earth, to move at what speed?
    A. 0;
    B. ½ c;
    C. Near c;
    D. 2 c;
    E. Near infinite speed.

  19. On your way back from Alpha Cen, you appear to me, watching you through a telescope on Earth, to move at what speed?
    A. 0;
    B. ½ c;
    C. Near c;
    D. 2 c;
    E. Near infinite speed.

    Th 2009 Sep 10:

  20. What “breaks the symmetry” between you and your twin, that allows the twin to be younger than you on return?
    A. On the outward journey, the velocity at which the twin sees you recede is different from the velocity at which you see the twin recede; and then on the return journey, the velocity at which the twin sees you return is different from the velocity at which you see the twin return.
    B. There is no difference, so in fact you must both age the same.
    C. Twin moved through space, whereas you did not.
    D. Twin accelerated (at Alpha), whereas you did not.
    E. Twin experienced a sudden loss of time at Alpha.

  21. You on Earth watch your twin through a telescope, and the twin watches you through a telescope. Which of the following is true?
    A. You both see each each other's clocks slowed down, on both the outward and return journeys.
    B. You both see each other's clocks slowed down on the outward journey, speeded up on the return journey.
    C. You both see each other's clocks speeded up on the outward journey, slowed down on the return journey.
    D. You see the twin's clock slowed down on both the outward and return journeys, whereas the twin sees your clock speeded up on both the outward and return journeys.
    E. You see the twin's clock slowed down on the outward journey and speeded up on the return journey, whereas the twin sees your clock speeded up on the outward journey and slowed down on the return journey.

  22. Your twin watches you on Earth through a telescope. At the moment that the twin accelerates at Alpha, the twin sees your clock:
    A. Run at the same slowed-down rate both before and after accelerating.
    B. Suddenly change from 2 years to 8 years.
    C. Suddenly speed up.
    D. Suddenly slow down.
    E. Change from running forward to runing backward.

    T 2009 Sep 15:

  23. When you accelerate to relativistic velocities, the view ahead appears to shrink. Why?
    A. Because you are moving away from the scene ahead.
    B. Because of Lorentz contraction.
    C. Because of special relativistic aberration.
    D. Because acceleration curves space.

  24. If you travel through a scene at near the speed of light, clocks attached to the scene ahead appear:
    A. slowed down compared to your own clock;
    B. to run the same rate as your own clock;
    C. speeded up compared to your own clock.

  25. Very Long Baseline Interferometry (VLBI) observations of the quasar 3C273 show blobs emerging at 8c. This indicates that:
    A. The jet is moving faster than c.
    B. Special Relativity is wrong.
    C. The blob is not a parcel of matter, but rather a wave of brightness passing along the jet.
    D. The jet is pointed almost towards us, and is moving at close to c.
    E. The jet is pointed away from us, and is moving at close to c.

  26. Why is a second jet not observed in 3C273?
    A. There is no second jet.
    B. Aberration bends the second jet out of view.
    C. The second jet is relativistically dimmed out of view.
    D. The second jet is relativistically redshifted out of view.
    E. The second jet is behind the quasar, which obscures it.

    Th 2009 Sep 17:

  27. In George Gamow's classic book “Mr. Tomkins in Wonderland”, Mr. Tomkins has a dream that the speed of light is 30mph. In the dream, passing bicyclists appear Lorentz contracted along the direction of their motion. Is Mr. Tomkins' dream correct?
    A. Yes.
    B. No.

  28. You pass through a scene at near the speed of light. Clocks on objects ahead of you appear speeded by exactly the same amount as the frequencies of photons of light from those objects appear increased. True or false?
    A. True.
    B. False.

  29. You pass through a scene at near the speed of light. The brightness of objects, as measured by the number of photons you see from them per unit time, appears increased by exactly the same amount as the frequencies of clocks on those objects appear increased. True or false?
    A. True.
    B. False.

    T 2009 Sep 22:

  30. Suppose you watch this scene while falling freely. According to the Principle of Equivalence, what kind of trajectory will the cannonball follow from your perspective (relative to you)?
    A. A vertical line.
    B. A straight line.
    C. A curved (parabolic) line.

  31. Standing on the surface of the Earth, you hold a negative mass object in your hand. According to the Principle of Equivalence, which way does the negative mass object fall when you drop it?
    A. Down to the floor;
    B. It justs hangs there in mid-air, falling neither down nor up;
    C. Up to the ceiling;
    D. None of the above.

  32. According to Special Relativity, does B see the light from A to be redshifted or blueshifted?
    A. B sees the light to be redshifted (lower energy) compared to A.
    B. B sees the light to have the same energy as A.
    C. B sees the light to be blueshifted (higher energy) compared to A.

  33. You are in flat space. You swing a clock on a rope in a circle around you, so that the clock is moving at near the speed of light relative to you. According to Special Relativity, the clock will appear to you to tick:
    A. Slow;
    B. At the same rate as your own clock;
    C. Fast;
    D. None of the above.

  34. In the situation of the previous question, the object therefore appears to you (according to Special Relativity):
    A. Redshifted;
    B. Neither redshifted nor blueshifted;
    C. Blueshifted.

    Th 2009 Sep 24:

  35. According to Thorne Ch 2, Einstein came up with the Principle of Equivalence:
    A. In 1905, the same year he published his theory of Special Relativity;
    B. In 1907, while preparing an invited review on Special Relativity;
    C. In 1915, after 10 years of intermittent work;
    D. Over a period of several decades, up to nearly the end of his life in 1955;
    E. Actually it was Poincaré, not Einstein, who first proposed the Principle of Equivalence.

  36. According to the river model of black holes, a person who falls through the horizon of a black hole appears to an outside observer to freeze and become highly redshifted at the horizon because:
    A. the black hole freezes at its horizon, and never actually collapses;
    B. the person freezes at the horizon, and never actually falls through;
    C. the curvature of space becomes infinite at the horizon;
    D. the closer to the horizon a photon is emitted, the longer the photon takes to forge against the inrushing torrent of space to reach an outside observer;
    E. it's not true: an outside observer sees the infaller become highly speeded up and blueshifted.

  37. According to the river model of black holes, a person who falls through the horizon of a black hole:
    A. experiences time to come to a halt at the horizon;
    B. experiences an infinite curvature, a singularity, at the horizon;
    C. is tidally torn apart at the horizon;
    D. sees an infinitely bright shaft of light directly above them at the horizon;
    E. experiences nothing special at the horizon.

    Tue 2009 Sep 29:

  38. What is a Gamma-Ray Burst?
    A. An energetic burst of gamma rays from the center of the Milky Way.
    B. An energetic burst of gamma rays from distant galaxies.
    C. The sign that a new star is born.
    D. A sign of extraterrestrial life.
    E. A burst of gamma-rays with duration between 1000 seconds and 1 day.

  39. What is the likely origin of a long duration Gamma-Ray Burst?
    A. The merger of two neutron stars.
    B. The merger of a neutron star and a black hole.
    C. The collapse of a massive, rapidly rotating star.
    D. The collapse of a low-mass star.
    E. The merger of two neutron stars or a neutron star and a black hole.

  40. What is the likely origin of a short duration Gamma-Ray Burst?
    A. The merger of two neutron stars.
    B. The merger of a neutron star and a black hole.
    C. The collapse of a massive, rapidly rotating star.
    D. The collapse of a low-mass star.
    E. The merger of two neutron stars or a neutron star and a black hole.

    Th 2009 Oct 1:

  41. According to Thorne Ch 2, an astronaut in outer space can detect that spacetime is curved from:
    A. measuring the speed of light (with ruler, mirror, and clock);
    B. the presence of a gravitational force;
    C. the presence of a tidal force (difference in gravitational force between two points a small distance apart);
    D. outer space is empty, so spacetime there must be flat, not curved;
    E. the Principle of Equivalence implies that the astronaut cannot detect that spacetime is curved.

  42. If nothing can escape from a black hole, how can its gravity escape?
    A. Gravity is a curvature of space, and does not need to escape.
    B. A person outside the BH experiences the gravity of the matter that long ago collapsed to, or fell into, the BH.
    C. Gravity travels faster than light.

    T 2009 Oct 6:

  43. A gamma-ray burst is thought to be produced by what cosmic event?
    A. The explosive evaporation of a mini-black hole by Hawking radiation.
    B. A star quake on the surface of a neutron star.
    C. The merger of two black holes.
    D. A jet that emerges from a massive star whose core collapses to a black hole.
    E. A white hole.

  44. According to Orosz's table, what is the probable mass of the black hole in Cygnus X-1?
    A. 1–2 solar masses;
    B. 0–13 solar masses;
    C. 4–13 solar masses;
    D. 7–13 solar masses;
    E. none of the above.

  45. How do astronomers measure the mass of the black hole at the center of the Milky Way?
    A. By measuring the radius of the black hole's horizon.
    B. From the velocities and distances of stars moving around it.
    C. From the brightness of the radio source Sgr A*.
    D. From the redshift of stars and gas falling through its horizon.

  46. The curve of enclosed mass versus radius has a flat part, then an upturn at larger radius? What mass causes these?
    A. All the mass is produced by stars.
    B. All the mass is produced by a black hole.
    C. A point mass causes the flat part; stars cause the upturn.
    D. A point mass causes the flat part; an accretion disk causes the upturn.
    E. A star causes the flat part; a black hole cause the upturn.

    Th 2009 Oct 8:

  47. How do astronomers conclude that a compact object in an x-ray binary is a black hole, as opposed to something else (such as a neutron star)?
    A. More than 3 solar masses in a space smaller than a white dwarf.
    B. The compact object is black.
    C. The compact object shows gravitational lensing.
    D. There is no sign of a pulsar or of pulsations.

  48. What evidence most convincingly suggests that there is a supermassive black hole at the center of our own Milky Way?
    A. The black hole causes gravitational lensing.
    B. The supermassive black hole is in an x-ray binary star system.
    C. Hubble Space Telescope observations show gas swirling down a vortex.
    D. A relativistic jet is seen coming out of the core of the Milky Way.
    E. Measurements of the velocities of stars at the center of the Milky Way indicate a large mass in a small space.

  49. Karl Schwarzschild assumed a system of spacetime coordinates arranged to be at rest relative to distant stars. He found that the coordinates became singular at the horizon. Why?
    A. Because there is a singularity at the horizon.
    B. Because there is no rest frame at the horizon.
    C. Because an object becomes infinitely redshifted at the horizon.
    D. Because the black hole becomes infinitely curved at the horizon.

  50. Schwarzschild's time coordinate became spacelike inside the horizon, while his radial coordinate became timelike. What does this imply?
    A. Time stops inside the horizon.
    B. Black holes are highly curved inside the horizon.
    C. There is a singularity inside the horizon.
    D. Space falls faster than light inside the horizon.

    Tue 2009 Oct 13:

  51. In GR, an embedding diagram is:
    A. A kind of spacetime diagram.
    B. A diagram that illustrates the curvature of space by embedding the space inside a fictional higher-dimensional space.
    C. A diagram that illustrates that curved space must exist physically inside a higher-dimensional space.
    D. A diagram that illustrates how objects move in curved space.
    E. A diagram that illustrates the depth of the gravitational potential.

  52. Does the Schwarzschild geometry describe the geometry of empty space around the Sun?
    A. Yes, to a good approximation.
    B. No, not at all.

  53. If a star, when it collapses to a black hole, appears to all outside observers to freeze forever at its horizon, does it ever actually collapse?
    A. Yes.
    B. No.
    C. It depends on your frame of reference.

  54. When the mass of a black hole increases, its horizon expands. Does the horizon appear to engulf stuff that previously fell through the horizon?
    A. Yes, stuff that previously fell into the black hole disappears.
    B. No, stuff that previously fell into the black hole remains frozen at the horizon, appearing to expand with the horizon.

    Th 2009 Oct 15:

  55. What lies the other side of the horizon of a realistic astronomical (as opposed to idealized mathematical) black hole?
    A. A parallel universe.
    B. A wormhole.
    C. A white hole.
    D. Empty space surrounding a singularity.
    E. The remnant of the star that collapsed to the black hole.

  56. Why is the Reissner-Nordström solution for the interior of an electrically charged black hole, which assumes that the black hole is empty of matter except at the singularity, inconsistent?
    A. Because a charged black hole would quickly neutralize itself.
    B. Because it contains a wormhole and white hole to a new universe.
    C. Because it predicts that a huge density of mass-energy collects at the inner horizon.
    D. Because it contains a naked singularity.
    E. Because it is gravitationally repulsive in its core, so that infalling matter and charge would not fall to the singularity, and the black hole would not be empty.

  57. From the point of view of an observer outside the outer horizon of a white hole, is the white hole gravitationally attractive or gravitationally repulsive?
    A. Attractive.
    B. Repulsive.
    C. Neither.

  58. If you free-fall towards the white hole, attempting to fall into it, what happens?
    A. The white hole repels you, so you cannot fall in.
    B. The white hole attracts you, but you can get no closer than its horizon.
    C. The white hole spontaneously morphs into a black hole, which you fall into.

    Tue 2009 Oct 20:

  59. On this Penrose diagram, what aspect of the infaller's worldline indicates that it is a possible worldline?
    A. The line points upward at less than 45o from vertical.
    B. The line is at 45o from vertical, and therefore lightlike.
    C. The line lies inside the Universe.
    D. The line goes through the horizon.
    E. The line terminates at the singularity.

  60. In the BHFS visualization of the Schwarzschild black hole, which object is the antihorizon?
    A. The gravitationally lensed image of the outside Universe.
    B. The Einstein ring.
    C. The dark red grid.
    D. The blue-white grid.
    E. It's not visible in the visualization.

    Th 2009 Oct 22:

  61. Which of the following did the Andromeda movie get right?
    A. The Andromeda had normal brightness.
    B. The spectrum of light from Andromeda was normal.
    C. The Andromeda was not torn apart by the tidal force from the stellar-mass black hole;
    D. When the Andromeda came back up off the horizon, it had lost 300 years;
    E. The Andromeda was pulled by the salvage ship off its frozen position on the horizon.

    Tue 2009 Oct 27:

  62. What does the silence (in the first scene of “Contact”) mean?
    A. Sound waves cannot go through space.
    B. Radio waves cannot go through space.
    C. Radio waves from Earth have not yet reached this distance.
    D. Radio waves from Earth are too faint to reach this distance.
    E. The Universe is large.

  63. What will Ellie Arroway's boyfriend Palmer Joss turn out to be, professionally? (What would generate most conflict?)
    A. A scientist.
    B. A journalist/writer.
    C. A religious person.
    D. A multi-billionaire.
    E. A superhero.

  64. Who does Ellie meet on the beach?
    A. Herself as a young girl.
    B. Drumlin.
    C. Her father.
    D. An alien, posing as her father.
    E. God.

    Th 2009 Oct 29:

  65. Who is the hero of this movie?
    A. Captain Dan Holland (Robert Forster).
    B. Dr. Kate McCrae (Yvette Mimieux).
    C. The robot, Vincent.
    D. The black hole.
    E. There isn't a discernible hero?

  66. Why does the dialog suck?
    A. Because the script writer cannot write.
    B. Because it's a Walt Disney movie aimed at kids.
    C. Because the characters are wooden, characterless.
    D. Because the characters talk at each other, not to each other.
    E. Because there is no conflict between the characters.

  67. What is the best way to avoid being pulled into the black hole?
    A. Fire rockets continuously.
    B. Invent anti-gravity (the movie solution).
    C. Go into orbit, rely on centrifugal force.
    D. Reduce the mass of the ship by throwing almost everything overboard.
    E. Fall into the black hole and get frozen at its horizon.

  68. Who will the villain turn out to be?
    A. Journalist Harry Booth (Ernest Borgnine).
    B. Dr. Alex Durant (Anthony Perkins, the Psycho guy).
    C. A mad German scientist who wears a white coat and who has turned all his crew into mindless robots.
    D. Maximillian, an evil robot.
    E. There will not be a discernible villain.

    Tue 2009 Nov 3:

  69. When you, a human, try to compress ordinary solid or liquid matter, what happens to the electrons orbiting nuclei in atoms?
    A. They orbit much slower.
    B. They hardly change their orbits.
    C. They orbit much faster.
    D. They move so fast that they escape the nuclei.
    E. They jiggle around randomly.

  70. Planets are made of solid/liquid matter, which is almost incompressible. Their density (mass/volume) equals atomic density, which is constant. What does the imply about the relation between mass M and radius R of planets?
    A. The radius R is constant, independent of mass M.
    B. M µ R.
    C. M µ R2.
    D. M µ R3.
    E. M µ R1/3.

  71. Suppose you put an electron in a box and cooled the box to absolute zero temperature (in other words, removed as much energy as possible from the box). Would the electron:
    A. Stop moving?
    B. Have a small but finite velocity?

  72. Suppose you made the box smaller (and kept it at absolute zero temperature). Would the electron:
    A. Remain at rest?
    B. Go slower?
    C. Go faster?
    D. Stay the same velocity?
    E. You could not make the box smaller.

    Th 2009 Nov 5:

  73. What kind of pressure holds up a white dwarf star against its gravity?
    A. Atomic pressrure.
    B. Nuclear pressure.
    C. Gas pressure of a hot plasma.
    D. Electron degeneracy pressure.
    E. Neutron degeneracy pressure.

  74. If you add 0.02 solar masses to a 1.39 solar mass white dwarf, then its radius will:
    A. decrease slightly;
    B. increase slightly;
    C. collapse to a neutron star;
    D. collapse to a black hole;
    E. explode.

    Tue 2009 Nov 10:

  75. The transition between atomic pressure and electron degeneracy pressure in cold matter at very high density occurs when:
    A. The matter is cooled to absolute zero temperature;
    B. The matter is heated to the point where the electrons are ionized;
    C. The electrons are compressed to the point where their velocities exceed the atomic velocity c/137;
    D. The electrons are compressed to the point where their velocities approach the speed of light c;
    E. The electrons and protons fuse into neutrons.

  76. The fact that pulsars were observed to pulse at several different radio frequencies ruled out the possibility that pulsars were LGM (Little Green Men). Why?
    A. Because any signal from LGM would be too faint to be detectable.
    B. Because LGM would probably not use radio waves.
    C. Because LGM would emit only at a single narrow frequency.
    D. Because LGM would emit a complicated signal, not just pulses.
    E. Because the probability of LGM existing is tiny.

  77. The masses of neutron stars observed in x-ray binary systems are all consistent with 1.4 solar masses. What is the significance of this mass?
    A. It is the maximum mass of a white dwarf.
    B. It is the maximum mass of a neutron star.
    C. It is the minimum mass of a black hole.
    D. It is the maximum mass of a black hole.
    E. It is probably just a coincidence.

    Th 2009 Nov 12:

  78. Andrea Ghez was one of the astronomers featured on the Nova program. What has Andrea Ghez been doing?
    A. She has been observing large numbers of stellar-sized black holes in the Milky Way.
    B. She has been discovering that almost every large galaxy has a supermassive black hole at its center.
    C. She has been following the orbits of stars around the black hole at the center of the Milky Way.
    D. She has observed gigantic jets from supermassive black holes, and their effect on the surrounding galaxy.
    E. She has been observing gamma-ray bursts and afterglows.

  79. What observational evidence did the Nova program show that suggests that supermassive black holes affect the galaxies they live in?
    A. Radio observations reveal that jets from supermassive black holes blow huge bubbles in the surrounding galaxy.
    B. Hubble Space Telescope observations show that almost every large galaxy harbors a supermassive black hole.
    C. Gamma-ray observations detect gigantic bursts from supermassive black holes.
    D. Gravitational wave observations reveal merging supermassive black holes.

  80. What kind of satellite did the Nova program show being sent into space on a rocket, and then taking observations?
    A. A radio satellite, VLBI, designed to measure superluminal jets from black holes.
    B. A microwave satellite, WMAP, designed to detect radiation left over from the Big Bang.
    C. An infrared satellite, Kepler, designed to detect Earth-like planets.
    D. A gamma-ray satellite, Swift, designed to detect Gamma-Ray Bursts.
    E. A gravitational wave satellite, LISA.

    Tue 2009 Dec 1:

  81. Which slingshot trajectory around the moon will send the rocket furthest out in the solar system?
    A.
    B.

  82. When two black holes spiral together and merge, the mass of the merged black hole is:
    A. More than the sum of the masses of the two individual black holes.
    B. Exactly equal to the sum of the masses of the two individual black holes.
    C. Less equal to the sum of the masses of the two individual black holes.
    D. Could be either more or less than the sum of the masses of the two individual black holes.

  83. A more massive black hole produces Hawking radiation with longer wavelength. Therefore a more massive black hole produces Hawking radiation that is _____ energetic, and therefore has a _____ Hawking temperature.
    A. Less, lower.
    B. More, lower.
    C. Less, higher.
    D. More, higher.
    E. None of the above.

    Tue 2009 Dec 8:

  84. Would you vote in favor of making a baby Universe?
    A. I think that it is immoral to attempt to make a baby Universe. I vote no.
    B. If this is the only way that our Universe can reproduce, then I think society has a moral duty to make it happen. I vote yes.
    C. I don't think society should waste resources attempting to make a baby Universe. I vote no.
    D. I don't have a strong moral opinion, but I support the notion that society should attempt to make a baby Universe. I vote yes.
    E. I don't really care either way. I probably won't bother to vote.

  85. If society were presented with the one-time opportunity to make a baby Universe, what do you think the eventual outcome would be?
    A. All out war between the yes and no factions.
    B. Fierce political discussion, resolved by the democractic process.
    C. Nothing. Society would not care, and would just go about its business.

  86. You are the leader of the “No-baby-Universe” faction. You believe deeply that your cause is right. You strive for right. But your faction has lost the vote. What do you do?
    A. Continue to argue non-violently for your cause.
    B. Fight for right. Start a guerilla war.
    C. Spread disinformation about your opponents and their theory of making baby Universes.

  87. How should the movie end?
    A. As the science says: the people outside the black hole never know whether a baby Universe was made, or what might be the nature of that baby Universe.
    B. The baby Universe should expand out into the old Universe, destroying it, and starting afresh.
    C. Somehow there is an unexpected line of communication from inside the black hole to outside, that allows people outside the black hole to discover what happened.
    D. Postpone the conclusion to a sequel.
    E. Something else.

 Black Hole silhouetted against the Milky Way Fall 2009 ASTR 2030 Homepage

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