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Q & A: thermal radiation

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Most recent answer: 05/08/2017
Q:
If the "jiggling of molecules" is eventually transferred into infared and sent into space; does that imply that if every thing and creature on earth stopped moving and interacting the earth would overload from energies brought in from space? Unlikely but are we keeping this planet alive by destroying it?.. in a sense.
- Ivan (age 25)
Cairns,Queensland
A:

The sorts of big motions you're thinking of don't have much of anything to do with the thermal radiation, the way that energy escapes from the earth. Living things do affect the earth's temperature  somewhat, for example by green plants absorbing some solar radiation that would otherwise bounce back into space, but even without any living things there would be a balance between solar radiation in and infrared radiation out with the earth at about its current average temperature. Of course, the biggest changes now are coming from one particular species- us- emitting CO2 and CH4, gases that slow down the rate that the infrared escapes and thus heat the earth up. 

From the point of view of physics, the possible upcoming changes (say a 3% change in absolute temperature, ~9K) are not all that big a deal. For biological creatures (us, again) who have to live here, however, that's a very big deal.

Mike W.


(published on 05/08/2017)

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