Author Question: When we see that a spectral line of a galaxy is broadened, that is, spanning a range of wavelengths, ... (Read 35 times)

neverstopbelieb · **on:** Jul 27, 2018

When we see that a spectral line of a galaxy is broadened, that is, spanning a range of wavelengths, we conclude that

A) we do not have very good resolution of a star's orbital velocity.
B) there are many stars traveling at extremely high orbital velocities.
C) there are different Doppler shifts among the individual stars in the galaxy.
D) we are actually measuring the orbital velocity of a cloud of atomic gas.
E) we are actually measuring the orbital velocity of dark matter.

Question 2

The curvature of spacetime around a black hole is so extreme that outward-going signals cannot escape.

Indicate whether the statement is true or false