flacaltenn
Diamond Member
Once the the suns energy is gone it will cool very rapidly as it can not hold energy. What little energy is absorbed by the atmosphere will be emitted to space very quickly as there is nothing to stop it in the atmosphere. Its mass is incapable of holding energy for more than 1-2 seconds.
Then you go off the rails.
How does the atmosphere lose energy to space? N2 neither absorbs nor emits IR.
The N2 indefinitely holds on to its stored energy simply by staying in a gaseous phase, suspended in the gravity field. During daylight the surface inputs energy to the atmosphere, which is then returned at night.
N2 certainly emits the energy it absorbs via collisions with other molecules...it conducts till such time as it can't, then it radiates till it reaches its equilibrium temperature...ditto for O2 and argon...
You like to claim that every thing radiates till it becomes inconvenient then N2 doesn't radiate? How quaint.
Everything DOES radiate. Just not in the IR band.. To get coupled heating between objects from radiative transfers they have to be tuned to each other. And since the earth's surface is "kinda" like a black body radiator, it's major emission/absorptions bands are ALL mostly IR. So unless the gas has emission bands in that RANGE, no IR heating will result.
Liquid nitrogen and oxygen are "blue tinted". Go look at some pics. That's where the bulk of their emission bands are. But if you heat EITHER ONE to high enough temperature -- they will dissassociate the N2 bonds and reassociate them which causes emission in the IR range. That's NOT gonna happen very much in the atmosphere unless chemical action is taking place.
Heating of N2 in atmos is therefore mostly from convective (actual) heat transfer. But I'm not sure that Ian is right about the system "only losing heat to the ground" during convection, because EVERY component of the greenhouse has a LARGE net loss to the sky. The GHouse gases are only retarding that popsicle effect..