Exam 15: Black Holes: Matters of Gravity

Suppose an observer were far from a planet that had a very strong gravitational field, and a light wave reaches the observer from a source of hydrogen (H _$\alpha$ ) light on the surface of the planet. For an H _$\alpha$ light source in the observer's own spaceship, the wavelength is 656.3 nm. What wavelength does the observer see when looking at the light source on the planet?

Which of these statements correctly describes "cosmic censorship"?

One prominent feature recently identified within many energetic close binary star systems as a result of their mutual interaction and mass exchange is

The formation of supermassive black holes

What is the event horizon of a black hole?

According to Einstein's theory of general relativity, if one watches a clock from a distant location as it is moved closer to a source of gravity, one will see the clock

Why do astronomers seek to measure gravitational waves simultaneously with at least three detectors?

When particle-antiparticle pairs are created just outside the event horizon of a black hole, one member can escape while the other enters the black hole. What is the name of this stream of particles leaving a black hole?

Suppose an astronaut is aboard a spaceship that is passing Earth at 80% of the speed of light. The astronaut sees a clock on Earth tick off 5 seconds. How much time elapses on the astronaut's own clock while this is happening?

What is believed to be the maximum mass for a neutron star?

What is believed to be the solar mass of the black hole candidate at the center of the galaxy M87?

The Schwarzschild radius is

How does the diameter of a black hole (size of the event horizon) depend on the mass inside the black hole?

One day, while straying dangerously close to a black hole, an astronaut notices that no matter how hard he tries to remain at rest, he is inevitably drawn into the black hole unless he keeps moving. What does this tell an observer about the black hole?

Suppose a virtual particle-antiparticle pair appears just outside the event horizon of a black hole, and that each particle is the same distance from the center of the black hole. What will happen in this case?

Where should an astronomer look for a supermassive black hole?

Which of these sources sometimes has an afterglow visible at optical and radio wavelengths?

Which of these has NOT been identified as the progenitor of at least some gamma-ray bursts?

In the context of black holes, what is a wormhole?

Where is the event horizon of a black hole located?