If you are standing on the floor then your action (or lack of action) can count as a test of

The total amount of illumination changes during the lunar cycle of phases.

In the Northern Hemisphere, the sunlight moves from right to left across the surface of the Moon during the waxing phases.

Astronomy is pseudoscience.

Cosmic rays are electromagnetic radiation.

Ancient astronomers thought the heavens were perfect circles, spheres, and unblemished.

A lunar eclipse that occurs when the Moon moves completely into Earth’s umbral shadow is called

Star A has an apparent visual magnitude of 13.4 and star B has an apparent visual magnitude of 15.4. Star A is ____ than star B.

An eclipse of the Moon (lunar eclipse) as seen from Earth, happens when

If a satellite is in orbit around Earth and the satellite’s altitude is decreased, then the circular velocity __________________.