Moon Pi and Mountain Shadow
14.03.2025

What phase of the Moon is 3.14 radians from the Sun? The Full Moon, of course. Even though the Moon might look full for several days, the Moon is truly at its full phase when it is Pi radians (aka 180 degrees) from the Sun in ecliptic longitude.

Lunar Dust and Duct Tape
17.04.2004

Why is the Moon dusty? On Earth, rocks are weathered by wind and water, creating soil and sand. On the Moon, the long history of micrometeorite bombardment has blasted away at the rocky surface creating a layer of powdery lunar soil or regolith. This lunar regolith could be a scientific and industrial bonanza.

Lunar Dust and Duct Tape
10.11.2001

Why is the Moon dusty? On Earth, rocks are weathered by wind and water, creating soil and sand. On the Moon, the long history of micrometeorite bombardment has blasted away at the rocky surface creating a layer of powdery lunar soil or regolith. This lunar regolith could be a scientific and industrial bonanza.

Mimas: Small Moon with a Big Crater
25.04.1999

Mimas is one of the smaller moons of Saturn but shows one of the largest impact craters. In fact, if the impact had been much greater, it would have disrupted the entire satellite. The large crater has been named Herschel after the 1789 discoverer of Mimas, Sir William Herschel.

APOD: 2023 January 16 Б Moon Enhanced
16.01.2023

Our Moon doesn't really look like this. Earth's Moon, Luna, doesn't naturally show this rich texture, and its colors are more subtle. But this digital creation is based on reality. The featured image is a composite of multiple images and enhanced to bring up real surface features.

Lunar Occultation of Venus
2.06.2022

On May 27 Venus rose as the morning star, near the waning crescent Moon in a predawn sky already full of planets. It was close on the sky to the Moon's crescent and a conjunction of the second an third brightest celestial beacons were enjoyed by skygazers around the world.

Tycho and Clavius
5.08.2021

South is up in this detailed telescopic view across the Moon's rugged southern highlands. Captured on July 20, the lunar landscape features the Moon's young and old, the large craters Tycho and Clavius.

APOD: 2025 January 15 Б Wolf Moon Engulfs Mars
15.01.2025

Does the Moon ever engulf Mars? Yes, but only in the sense that it moves in front, which happens on rare occasions. This happened just yesterday, though, as seen from some locations in North America and western Africa.

Full Moon, Full Mars
18.01.2025

On January 13 a Full Moon and a Full Mars were close, both bright and opposite the Sun in planet Earth's sky. In fact Mars was occulted, passing behind the Moon, when viewed from some locations in North America and northwest Africa.

APOD: 2026 May 9 Б Messier Craters in Stereo
9.05.2026

Many bright nebulae and star clusters in planet Earth's sky are associated with the name of astronomer Charles Messier from his famous 18th century catalog. His name is also given to these two large and remarkable craters on the Moon.