Atmosphere of Earth surface. The refractive index of air depends on temperature, giving rise to refraction effects when the temperature gradient is large. An example of such effects is the mirage. "Atmospheric circulation" is the large-scale movement of air through the troposphere, and the means (with ocean circulation) by which heat is distributed around Earth. The large-scale structure of the atmospheric circulation varies from year to year, but the basic structure remains fairly constant because it is determined by Earth's rotation rate and the difference in solar radiation between the equator and poles. The first atmosphere consisted of gases in the solar nebula,
Atmosphere of the Moon on the order of just a few protons per cubic centimeter, it is virtually a vacuum in comparison with the atmosphere of the Earth. The Moon may also have a tenuous "atmosphere" of electrostatically-levitated dust. See Moon dust for more details. In October 2017, NASA scientists at the Marshall Space Flight Center and the Lunar and Planetary Institute in Houston announced their finding, based on studies of Moon magma samples retrieved by the Apollo missions, that the Moon had once possessed a relatively thick atmosphere for a period of 70 million years between 3 and 4 billion years ago. This