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,
Where Do We Come From? What Are We? Where Are We Going? Where Do We Come From? What Are We? Where Are We Going? Where Do We Come From? What Are We? Where Are We Going? is a painting by French artist Paul Gauguin. Gauguin inscribed the original French title in the upper left corner: D'où Venons Nous / Que Sommes Nous / Où Allons Nous. The inscription the artist wrote on his canvas has no question mark, no dash, and all words are capitalized. In the upper right corner he signed and dated the painting: "P. Gauguin / 1897". The painting was created in Tahiti, and is in the Museum of