What is the best current method for determining the masses of stars?

Based on their colors, which of the following stars is hottest?

Match the objects with the method astronomers would use to determine their distance.

A 3 Msun star will end its life as a

Because the celestial sphere is not real, it is not a good scientific model.

The ___________ of a gas is a measure of the average speed of the particles in the gas.

Which type of spectrum would you expect to see from a star?

Match the Laws to their descriptions.

Why did Ptolemy have to introduce multiple circles of motion for the planets instead of a single, simple circle to represent the planet’s motion around the Earth?

Astronomers call the side of the Moon that always faces away from the Earth the dark side of the Moon.