Module 21

1. The telescope that uses lenses to bring visible light to a focus is a _____ telescope.

1. The telescope that uses mirrors to bring visible light to a focus is a _____ telescope.

1. Telescopes are placed _____ in order to most effectively collect X-rays and gamma rays.

1. The space exploration that landed astronauts on the Moon was _____.

1. _____ is the material blasted out of the Moon’s surface as a result of space-object impacts.

The theory that suggests the Moon is formed as a result of a collision between Earth and a Mars-sized object is called the _____ theory.

1. The daily rising and setting of celestial objects like the Sun is due to the _____ of Earth.

One reason different seasons occur on Earth is because Earth’s _____ is tilted 23.5° relative to the ecliptic.

When the moon waxes during its lunar cycle, the amount of its sunlight portion that we see appears to _____ in size.

When the moon wanes during its lunar cycle, the amount of its sunlight portion that we see appears to _____ in size.