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Interesting.
Martin and Jonah: I don't think he meant "new heat" in that way. Language that drives a physicist nuts, yes, but not claims of zero-point energy from parked cars!
Contributing to warming? A wee bit.
Picture a vast greenhouse the size of, say, France, sitting on the surface of the Earth. The green house "retains heat" in two ways: first, by preventing the escape of longer-wavelength light, making that light bounce around uselessly, being converted into longer- and longer-wavelength light until a substantial fraction of those little jiggles are mere heat. Second, it prevents heated air from circulating, so that the inside of the greenhouse is much warmer than the outside (in a parked car, the temperature above ambient can be a good 40F.) The second factor doesn't matter as much for this issue - heat here in the troposphere, heat there in the troposphere, it's basically the same - but the first one is important.
Now imagine that greenhouse, in a feat of green architecture, was constructed by sawing the rooftops off of the world's cars. Same basic idea, plus imagine the award-winning photos of the roof.
So it should contribute to the amount of longer-wavelength light bouncing around. BUT... not to large-scale warming.
Global warming is the result of the actual heat capacity of the atmosphere rising. This has happened not by just adding mass, but by adding particular substances - CO2, CH4, and various big, hunky molecules like Chanel No.5 - to the atmosphere. You can shoot lots of radiation at the Earth, but if the atmosphere doesn't have the wherewithal to retain it, out it goes into space. One of the effects of warming has been elevated nighttime temperatures. In other words, the heat is being held in by the stuff we're putting into the atmosphere. So. In that same way that, yes, some extra "heat energy" is being dumped into the atmosphere rather than fleeing into space as visible or short-wavelength IR. But although it may help make a Wal-Mart parking lot an unpleasant place for reasons other than simply being a Wal-Mart parking lot, it doesn't really contribute to global warming.
Disclaimer: I have attempted to hide my rudimentary knowledge of thermodynamics, compared to, say, Tom Twardowski, with flippant humor. Forgive me, my car was recently broken into and the computer stolen, so any excuse to portray automobiles as evil is welcome.
Marc Taylor
Coordinator, Andrus Planetarium
Hudson River Museum
511 Warburton Avenue
Yonkers, NY 10701
914 963 4550 x223
Fax 963 8558
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> -----Original Message-----
> From: [log in to unmask] [mailto:[log in to unmask]]
> Sent: Wednesday, September 06, 2006 1:55 PM
> To: [log in to unmask]
> Subject: heat: a thought exercise
>
>
> ISEN-ASTC-L is a service of the Association of
> Science-Technology Centers
> Incorporated, a worldwide network of science museums and
> related institutions.
> **************************************************************
> ***************
>
> I was chatting with a host at a wine-tasting event this past
> weekend in
> Sonoma, and as soon as he found out I was involved in the
> science museum
> field, he posed a challenge, and it threw me to the extent
> that I said I'd
> post it to the ASTC list and see where the chips fell.
>
> *****
> Here's the exercise:
>
> Imagine that you've parked your car outside on a hot summer
> day. When you
> open the doors after a couple of hours, you're blasted with
> the heat that
> has built up inside. Is this "new heat"? If so, could this
> (gazillions
> of cars sitting around) theoretically contribute to an excess
> of global
> heat (global warming)? To add to the exercise, imagine that this is
> taking place 10 million years ago, without the variables brought on by
> chemicals in the atmosphere.
> *****
>
> If you're like me, you'll have a knee-jerk reaction to this
> exercise, but
> then you may step back a mental notch and find yourself asking more
> questions than you thought you started out with, so I will
> stop here and
> not pollute the discussion with any of my own initial thoughts.
>
> My new friend is looking for equations and the like to prove
> the point -
> one way or the other - game on!!!
>
> **************************************************************
> *********
> More information about the Informal Science Education Network and the
> Association of Science-Technology Centers may be found at
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More information about the Informal Science Education Network and the
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