Black Holes Session

Question 1 of 12

What is the event horizon of a black hole?

The point of no return; the boundary beyond which nothing, not even light, can escape. The singularity at the center of the black hole. The region where Hawking radiation is emitted. The physical surface of the black hole.

Question 2 of 12

What is the singularity of a black hole?

The event horizon. The accretion disk surrounding the black hole. The region of spacetime where the curvature becomes infinite. The ergosphere of a rotating black hole.

Question 3 of 12

What is Hawking radiation?

The light emitted when matter crosses the event horizon. Theoretical black body radiation predicted to be emitted by black holes due to quantum effects. Radiation caused by gravitational lensing. Radiation emitted from the accretion disk.

Question 4 of 12

What is the Schwarzschild radius?

The radius of the ergosphere. The radius of the accretion disk. The radius of the singularity. The radius of the event horizon of a non-rotating black hole.

Question 5 of 12

Which of the following is a possible way for a black hole to form?

From the collision of two neutron stars. From the gravitational collapse of a massive star at the end of its life. From the accretion of matter onto a white dwarf exceeding the Chandrasekhar limit. All of the above.

Question 6 of 12

What is an accretion disk?

A disk of gas and dust orbiting a black hole. The singularity at the center of a black hole. The event horizon of a black hole. A type of galaxy.

Question 7 of 12

What is gravitational lensing?

The bending of light around massive objects, such as black holes. The stretching of spacetime near a black hole. The emission of light from the accretion disk. The process of a black hole merging with another black hole.

Question 8 of 12

What is the ergosphere of a rotating black hole?

The region inside the event horizon. The region outside the event horizon where it is impossible to remain at rest. The singularity. The accretion disk.

Question 9 of 12

Which of these is a direct method of detecting black holes?

Observing the bending of light around a black hole (gravitational lensing). Detecting X-rays emitted from the accretion disk of a black hole. Directly imaging the shadow of a black hole against a bright background. All of the above can be considered direct methods.

Question 10 of 12

What does the 'no-hair' theorem state about black holes?

Black holes have no physical surface. Black holes have no color. Black holes are fully described by only three externally observable properties: mass, electric charge, and angular momentum. Black holes are completely bald.

Astronomy | Black Holes