Back to Glossary

The Moon

The Moon is Earth’s only natural satellite—a rocky, cratered body about one‑quarter the diameter of Earth, orbiting at an average distance of approximately 384,400 km. It influences tides, stabilizes Earth’s axial tilt, and was formed about 4.5 billion years ago following a collision between Earth and a Mars-sized object.

Source: science.nasa.gov

APODs including "The Moon"

Observatory Aligned with Moon Occulting Jupiter

24/05/2023

Observatory Aligned with Moon Occulting Jupiter
Image Credit: Rick Whitacre; Text: Natalia Lewandowska (SUNY Oswego) / NASA APOD

Sometimes we witness the Moon moving directly in front of -- called occulting -- one of the planets in our Solar System. Earlier this month that planet was Jupiter. Captured here was the moment when Jupiter re-appeared from behind the surface of our Moon. The Moon was in its third quarter, two days before the dark New Moon. Now, our Moon is continuously half lit by the Sun, but when in its third quarter, relatively little of that half can be seen from the Earth. Pictured, the Moon itself was aligned behind the famous Lick Observatory in California, USA, on the summit of Mount Hamilton. Coincidentally, Lick enabled the discovery of a moon of Jupiter: Amalthea, the last visually detected moon of Jupiter after Galileo's observations. Gallery: Moon Occults Jupiter in 2023 May: Notable Submissions to APOD