If you drop a rock from a great height, about how fast will it be falling after 5 seconds, neglecting air resistance? 

Why are galaxies in the blue cloud blue?

What do astronomers consider heavy elements?

Briefly describe two key pieces of evidence that support the Big bang Theory.

Study this H-R diagram. Which of the following stars is the most massive? (The red arrows help you locate these stars on the diagram.)

What layer of the Sun are we seeing in this photograph, and in what wavelength band was it photographed?

What would happen inside the Sun if a slight rise in core temperature led to a rapid rise in fusion energy?

This photo shows an object located in the halo of our Milky Way galaxy. Notice the many bright red dots in the photograph. What are they?

The top panorama shows our view of the Milky Way in all directions as it appears in visible light. The bottom panorama shows the same view, but in a different wavelength of light. What wavelength band are we seeing in the bottom photo, and how do you know?

Suppose a particular star has a core that is undergoing several stages of fusion simultaneously, as shown in this diagram. Based on your understanding of stellar lives, the mass of this star is probably ____________.