|
Post by julianb on May 31, 2010 10:45:04 GMT
www.ilovemycarbondioxide.com/pdf/Greenhouse_Effect_on_the_Moon.pdfpinched from the 'NASA, Moon's Greenhouse Effect' thread that I just read. SoCold thinks it funny, obviously doesn't get its implications to greenhouse theory if the calculated no atmosphere temperature of Earth did not take this into consideration. I see from the PDF that Neptune does have a measured lapse rate!
|
|
|
Post by touko on May 31, 2010 12:17:18 GMT
"If you have a sealed syringe of air and you push down on the plunger the air inside will warm. This is because the molecules are in motion and repel each other. You would have to keep applying force to the plunger to stop it from being pushed back out by the motion of the molecules. If there were a vacuum outside, the heat would soon be lost, the air inside would cool and there would no longer be any need to push on the plunger."
As I've said elsewhere, there will be no increase of thermal energy in the gas, the existing heat will only be concentrated in a smaller volume, and therefore appears to have gained energy. That same overall energy would be lost from the syringe at all times regardless whether you apply pressure or not.
"But if you did the same inside a sealed room and kept pushing on the plunger for a very long time, eventually the force you applied to the plunger would have been converted to enough heat to warm the entire room."
Sorry, no, as no new energy would have been created at any point. The thermal content will always be that of the initial syringe, nothing will be added to it.
But Hairball you're in good company -- the perpeertum mobile has been the goal of many an amateur thinker for centuries!
Touko
|
|
|
Post by hairball on May 31, 2010 12:20:02 GMT
Thanks for the encouragement Tuoko, I'll try to live up to your high expectations.
Indulge me, though, what happens to the energy used to depress the plunger? Don't hot gases radiate heat faster than cold ones? Isn't gravity a force? Don't forces do work?
|
|
|
Post by touko on May 31, 2010 12:44:59 GMT
Your compression efforts will be converted to heat, and scattered around. That hotter gas will radiate hotter, but, remember, from within a smaller version of its volume. Eventually, the end result will be the same in all cases, the energy will be lost.
Forces alone don't do any work. Consider a permanent magnet, the hugest one there is, and stand by it for an energy release for any work to take place -- you will be waiting.
The work gravity may appear to be making for you on an object on its way towards the center of the planet is the result of someone or something having lifted the object away from the planet's center at some time previously. No free lunch there!
Touko
|
|
|
Post by hairball on May 31, 2010 13:12:50 GMT
Damn, I guess I'd better cancel my appointment with those venture capitalists then
|
|