Author Question: Which of the following best describes the meaning of declination and right ascension? A) They are ... (Read 47 times)

CBme · **on:** Jul 27, 2018

Which of the following best describes the meaning of declination and right ascension?

A) They are coordinates on the celestial sphere that are very similar to the coordinates of altitude and direction on Earth.
B) They are used to describe the locations and distances of stars that we see in the night sky.
C) They are coordinates on the celestial sphere, with declination telling us the angular distance of an object from the celestial equator and right ascension telling us how far around the celestial sphere an object is located from the vernal equinox.
D) They are terms used by astronomers to describe how the sky changes with the seasons.

Question 2

The best evidence for the existence of supermassive black holes is

A) very high orbital velocities in a very compact region.
B) evidence for jet velocities that approach the speed of light.
C) large quantities of high-energy emission such as X-rays and gamma rays, and radio emission from relativistic electrons.
D) huge dark regions in the centers of galaxies, where black holes have been sucking in the galaxy from the inside out.