HW 14

A  Our Sun will become a black holes at the end of its life.

B  A stellar-mass black hole can suddenly brighten after swallowing a clump of gas in the surrounding accretion disk; the light comes out from inside the event horizon.

C  Most pulsars are thought to be rapidly rotating black holes.

D  Black holes are generally more massive than three solar masses because neutron degeneracy pressure can hold up smaller masses.

A  A black hole has an “event horizon” from which no light can escape, according to classical (i.e., non-quantum) ideas.

B  A black hole that has reached an equilibrium configuration can be described entirely by its mass, electrical charge and amount of spin (“angular momentum”).

C  Near the event horizon of a stellar mass black hole, tidal forces stretch objects apart.

D  Inside a black hole, matter is thought to consist primarily of iron, the end point of nuclear fusion in massive star.

A  the total mass of the galaxy.

B  the color of the galaxy.

C  the diminished brightness of starlight in the galaxy core, relative to surrounding areas.

D  the distance of the galaxy from the Milky Way Galaxy.

E  the speeds of the stars near the core.

A  Find star(s) orbiting a blank spot.

B  Identify an accretion disk emitting x-rays.

C  All of these answers would work.

D  Find an astrometric binary with a massive companion.

A  TRUE

B  FALSE

A  FALSE

B  TRUE

A  FALSE

B  TRUE

A  constant

B  sphere

C  singularity

D  orbit

A  radius, mass

B  charge, mass

C  density, mass

D  speed. light

A  emitting x-rays.

B  gamma-ray burst

C  ultra violet light

D  gamma-ray light

A  stellar mass

B  Schwarzschild radius

C  Einstein-Rosen Bridge

D  event horizon

A  stop

B  rotate

C  curve

D  drop