Measuring the Distance Between the Moon and Earth

There are several methods to calculate the distance between the Moon and the Earth:

Trigonometry

The distance between the Moon and Earth can be calculated using trigonometry. By measuring the angles between the Moon, Earth, and the Sun and using these angles to calculate the distance between the Moon and Earth.

Lunar Laser Ranging (LLR)

Lunar Laser Ranging involves reflecting laser beams off of mirrors placed on the Moon by the Apollo missions and measuring the time it takes for the light to travel to the Moon and back. This time measurement can then be used to calculate the distance between the Moon and Earth.

Radar Ranging

Radar ranging involves sending a radar signal to the Moon and measuring the time it takes for the signal to bounce back to Earth. This time measurement can then be used to calculate the distance between the Moon and Earth.

Astrometry

Astrometry is the study of the position and motion of celestial objects. By accurately measuring the position of the Moon in the sky and the position of the Earth, the distance between the two can be calculated.

The average distance between the Moon and Earth is about 384,400 kilometers (238,855 miles). However, the distance between the two is constantly changing due to the Moon's elliptical orbit around the Earth.