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One classical thermal escape mechanism is Jeans escape, [1] named after British astronomer Sir James Jeans, who first described this process of atmospheric loss. [2] In a quantity of gas, the average velocity of any one molecule is measured by the gas's temperature, but the velocities of individual molecules change as they collide with one another, gaining and losing kinetic energy.
Diagram showing displacement of the Sun's image at sunrise and sunset Comparison of inferior and superior mirages due to differing air refractive indices, n. Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. [1]
The Moon's density is substantially less than that of Earth, due to its lack of a large iron core. [3] On Earth , physical and chemical differentiation processes led to a crustal density of approximately 2700 kg/m 3 compared to the 3400 kg/m 3 density of the compositionally different mantle just below, and the average density of the planet as a ...
Blue light is scattered more than other wavelengths by the gases in the atmosphere, surrounding Earth in a visibly blue layer at the stratosphere, above the clouds of the troposphere, when seen from space on board the ISS at an altitude of 335 km (208 mi) (the Moon is visible as a crescent in the far background).
[106] [107] [108] Earth's surface is shaped by plate tectonics that formed the continental masses. [93] Earth's planetary magnetosphere shields the surface from radiation, limiting atmospheric stripping and maintaining life habitability. [109] The Moon is Earth's only natural satellite. [110] Its diameter is one-quarter the size of Earth's. [111]
The fact that the sky is not completely dark at night is easily visible. If light sources (e.g. the Moon and light pollution) were removed from the night sky, only direct starlight would be visible. The sky's brightness varies greatly over the day, and the primary cause differs as well.
Scientists warn that if carbon dioxide and other greenhouse gas emissions continue to rise at their current rates, Earth’s temperatures could increase dramatically in future decades, leading to catastrophic and irreversible climate change. The 10 largest emitters produced about 26.4 gigatons of carbon dioxide in 2013.
[13] [14] Similarly, Earth has an effective temperature of 255 K (−18 °C; −1 °F), [14] but a surface temperature of about 288 K (15 °C; 59 °F) [15] due to the greenhouse effect in our lower atmosphere. [5] [4] The surface temperatures of such planets are more accurately estimated by modeling thermal radiation transport through the ...