Blue light has higher frequency than red light. Thus, blue light has:

which of the following statements about the cosmic background radiation is not true?

(a) It has a temperature of about 3 degrees K about absolute zero.

(b) It is the result of moisture of radiation from many independent sources, such as stars and galaxies.

(c) It had a much higher temperatures in the past.

(d) It is isotropic.

What is the reason behind the smoothness of Io's surface?

What happens to gas as it freely expands?

When did the objects that we now see as asteroids and comets form in the solar system?

When your friend flies by you in a spaceship at half the speed of light, you observe that

What do we need to measure in order to determine a star's luminosity?

For someone standing in Charlottesville, the Sun is directly
overhead (at the zenith) and why
A. Never
B. Once per year
C. Twice per year
D. Four times per year
E. Every day at noon

What is the earliest time in the universe that we can directly observe?

What do we mean when we say that the universe is expanding?

In which of the following models will the universe stop expanding? 

A. Open Universe
B. Closed Universe
C. Steady State Universe
D. Critical Density Universe
E. All have an ultimate collapse.

What do we mean when we say that the sun is in gravitational equilibrium?

After a massive-star supernova, what is left behind?

The shadow cast by a simple stick or obelisk allowed ancient people to_______.

Which of these things poses the greatest hazard to communications satellites?

(a) Photons from the Sun

(b) Solar magnetic field 

(c) Protons from the Sun