Welcome Guest [Log In] [Register]
Sky Dragon is up and running. We need people to sign up and add content. Introduce yourself at the General discussion forum. Speak up to welcome a few others, start a thread, or contribute to someone else's thread.
Viewing Single Post From: The giant space ship example
gbaikie

Quote:
 
You used the wrong number for the power in watts heating the starship.


Right.
Ok so :
6.58e15 Watts. for starship maintain 10 C
Takes about 30 hours to drop 1 C
Or your number "8.2e4 seconds to drop one degree"
Which is a long time

Earth requires 1.74e17 watts sunlight [with some percentage of this added heat]
And on Earth unless one is in the tropics with high humidity one doesn't normally see such a low
rate of cooling.
And explanation of such low rate is starship has far more atmosphere per square
meter as compared to earth.
And accordingly it doesn't matter how much atmosphere whether half or double
one still requires 6.58e15 Watts. for starship maintain 10 C.

So accordingly anything that adds heat capacity will not makes any difference.
Water vapor adds enormous amount of heat capacity but that aspect of water vapor
will not make a difference.

So for the moment I will consider the above as resolved.

I do have questions outstanding regarding laspe rate- why should it have any effect on lowering the 6.58e15 Watts requirement.
And also when you turn off furnace where does most change in temperature occur. It seems since
bottom of atmosphere is warmest it would cool the fastest.

Other than above I think I can move on to effects from greenhouse gases.

PS: I said "We also have temperatures dropping by 100 K during couple hours on the Moon during a Lunar ellipse. "
I gave ref over dragonslayer:
http://diviner.ucla.edu/
http://www.diviner.ucla.edu/blog/?p=610
“The following plot shows data taken during successive orbits over a unit of lunar mare situated between 32 and 33 degrees north. The orbit path progressed from east to west (right to left), with each orbit separated by roughly two hours. The first two data swaths were taken before the eclipse, the three center swaths were taken during the eclipse, and the last two swaths were taken after the Moon had reemerged from Earth’s shadow. The data show an average decrease in surface temperature during the eclipse of around 100K, with some locations remaining warmer than others.”
Obviously the speed of drop has to due high starting point of temperatures of lunar surface- and low heat capacity of top most layer of regolith. I also think the sudden drop from solar eclipse on earth similarly starts from high temperature.
Related to this is that as sun gets closer to dusk one see fairly rapid drop in temperature in some areas- though late afternoon to near dusk can be warmest times of the day in some other places- and I would guess that when you have though situations fairly warm dusk, the nite also keeps fairly warm. and areas where cools rapidly before sun goes down will see rapid cooling at nite.

Another thing how high is atmosphere, say at point of 1/1000 of psi, and during this time of cooling in which furnace is off, does the atmosphere lower significantly in the 8.2e4 seconds?
And is that mainly why 10 C surface air doesn't cool very quickly?

My guess in which I got 100,000 2 GW reactors was considering the atmosphere as an averaged temperature. Which I think is in contrast to how you look at it- you regard the 10 C of surface temperature as determinative factor.
And I sort of see the atmosphere as one temperature, just different pressure. Or pressurized the one cubic meter of air at say 100,000' to pressure at surface and they will be close to same temperature.
Or similar way is that if you want a warm surface temperature [10 C] one will make the atmosphere much higher as compared to a surface temperature of say -50 C.
Edited by gbaikie, Dec 8 2011, 01:47 AM.
Offline Profile Quote Post
The giant space ship example · Physical theory for climate