Timeline for Why is everything floating in space so cold?
Current License: CC BY-SA 2.5
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| Feb 2, 2011 at 4:39 | comment | added | Omega Centauri | I presume by space, he means roughly the earth's distance from the sun. At 1 AU the solar instensity is roughly 1350 watts per meter squared. We would expect a space object to be nearly in radiative equilibrium. Shortwave solar energy absorbed equals longwave infrared energy emitted. The shortwave energy absorbed would be the solar constant time one minus the albedo (reflectivity)), times a geometric adjustment (1/4 for a sphere). And the infrared out is emissivity times sigma T**4 (Stefan Boltzmann). A planet like the earth is warmer because greenhouse gasses effectivly reduce emissivity. | |
| Feb 2, 2011 at 0:24 | history | answered | Lawrence B. Crowell | CC BY-SA 2.5 |