From a theoretical standpoint, what is a pulsar?
A) a star that alternately expands and contracts in size
B) a rapidly rotating neutron star
C) a neutron star or black hole that happens to be in a binary system
D) a binary system that happens to be aligned so that one star periodically eclipses the other
E) a star that is burning iron in its core
Question 2
What is the average temperature of the surface of the Sun?
A) 1 million K
B) 100,000 K
C) 10,000 K
D) 6,000 K
E) 1,000 K