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Saturn has a hot interior, reaching 11,700 °C (21,100 °F) at its core, and radiates 2.5 times more energy into space than it receives from the Sun. Jupiter's thermal energy is generated by the Kelvin–Helmholtz mechanism of slow gravitational compression; but such a process alone may not be sufficient to explain heat production for Saturn ...
In astronomy or planetary science, the frost line, also known as the snow line or ice line, is the minimum distance from the central protostar of a solar nebula where the temperature is low enough for volatile compounds such as water, ammonia, methane, carbon dioxide and carbon monoxide to condense into solid grains, which will allow their accretion into planetesimals.
Planetary habitability in the Solar System is the study that searches the possible existence of past or present extraterrestrial life in those celestial bodies. As exoplanets are too far away and can only be studied by indirect means, the celestial bodies in the Solar System allow for a much more detailed study: direct telescope observation, space probes, rovers and even human spaceflight.
Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...
[98] [99] However, once a red giant star reaches the horizontal branch, it achieves a new equilibrium and can sustain a new circumstellar habitable zone, which in the case of the Sun would range from 7 to 22 AU. [100] At such stage, Saturn's moon Titan would likely be habitable in Earth's temperature sense. [101]
Saturn’s rings are seen as viewed by NASA’s Cassini spacecraft, which obtained the images that comprise this mosaic at a distance of approximately 450,000 miles from Saturn April 25, 2007.
Strong stellar winds can also strip gas atoms from the top of an atmosphere causing them to be lost to space. To support an Earth-like atmosphere for about 4.6 billion years (Earth's current age), a moon with a Mars-like density is estimated to need at least 7% of Earth's mass. [20]
There are large variations in surface temperature over space and time on airless or near-airless bodies like Mars, which has daily surface temperature variations of 50–60 K. [18] [19] Because of a relative lack of air to transport or retain heat, significant variations in temperature develop. Assuming the planet radiates as a blackbody (i.e ...