Self Assessment Week 13

Question 12 According to the general theory of relativity, light and other radiation coming from a white dwarf or a neutron star should (and experiments show that it does) exhibit

a gravitational redshift

Question 13 From which of the following will a wave of light show the greatest gravitational redshift:

a white dwarf

Question 5 When a light wave leaves a region of strong gravity, compared to the same wave leaving a spaceship in empty space, the wave in strong gravity will have Correct!

all the characteristics listed are correct

Question 8 To predict whether a star will ultimately become a black hole, what is the key property of the star we should look at?

mass

Question 9 Some years after college (and after you recover from your astronomy class,) you get married and exchange gold rings with your sweetheart. What connection is there between the gold in those rings and recent observations of gravitational waves?

our new understanding is that significant amounts of gold in the universe are produced in the mergers of neutron stars, which can be detected with gravitational waves

Question 10 Far away from a black hole (at the distance of another star), which of the following is a possible way to detect it?

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

Question 6 When scientists say that "black holes have no hair", what do they mean? Correct!

that once a black hole forms, very little information can be extracted from it about the material that is now inside

Question 4 When astronauts aboard the International Space Station (ISS) in space let go of an orange, it just floats there. Why is that?

the ISS is falling around the Earth, and in free fall, things feel no weight

Question 14 In the first direct detection of gravitational waves by LIGO in 2015, the waves came from

the merger of two black holes

Question 7 According to Einstein's general theory of relativity, the stronger a star's gravity,

the slower time runs near it

Question 11 The first time that astronomers observed both gravitational waves and electro-magnetic waves from the same event, what they were observing was:

the spiraling toward each other of two neutron stars

Question 3 Which of the following statements about the way the mass of a white dwarf affects spacetime is correct?

the white dwarf mass will curve spacetime; light has to follow that curvature

Question 2 According to the general theory of relativity, the presence of mass

causes a curvature (or warping) of spacetime

Question 1 If you are in a freely falling elevator near the top of a tall building, as the elevator falls, your weight would be:

equal to zero - you would be weightless