Atmosphere of the Moon

The elevated presence of atomic and molecular particles in its vicinity compared to interplanetary medium, referred to as "lunar atmosphere" for scientific objectives, is negligible in comparison with the gaseous envelopes surrounding Earth and most planets of the Solar System.

[5][6] Otherwise, the Moon is considered not to have an atmosphere because it cannot absorb measurable quantities of radiation, does not appear layered or self-circulating, and requires constant replenishment due to the high rate at which its gases are lost into space.

One source of the lunar atmosphere is outgassing: the release of gases such as radon and helium resulting from radioactive decay within the crust and mantle.

[8] The elements sodium and potassium have been detected in the Moon's atmosphere using Earth-based spectroscopic methods, whereas the isotopes radon-222 and polonium-210 have been inferred from data obtained by the Lunar Prospector alpha particle spectrometer.

[10] While this greatly exceeds the density of the solar wind, which is usually on the order of just a few protons per cubic centimeter, it is virtually a vacuum in comparison with the atmosphere of the Earth.

Surveyor 7 observes levitating dust, a phenomenon named Lunar horizon glow can be seen
The thin lunar atmosphere is visible on the Moon's surface at sunrise and sunset with the lunar horizon glow [ 1 ] and lunar twilight rays, like Earth's crepuscular rays . This Apollo 17 sketch depicts the glow and rays [ 2 ] among the general zodiacal light [ 3 ] [ 4 ] .