Celestia Forums

Two of my students have found something weird today, with Celestia 1.4.1. I've checked at home with 1.5.0, and I have the same result as them, and I don't understand what is going on :

Selecting Venus gives me 229 Kelvin, while I get an higher score for Earth : 258 Kelvin. Why ? Earth is farter from the Sun than Venus, so should record a lower temperature. Can someone explain this to me ? Is this a bug ?

It's not a bug. Or rather, if there is a bug, it's a lack of documentation. The temperature displayed by Celestia is the radiative equilibrium temperature and does account for trapping of heat by greenhouse gases. The temperature is lower for Venus because its higher albedo relative to Earth's more than compensates for the fact that Venus is closer to the Sun.

Here's a thread with some more information:

http://www.celestiaproject.net/forum/viewtopic.php?t=2999

I'm considering removing the temperature from the list of information displayed by Celestia. It's confusing to a lot of people, and isn't a fundamental datum.

--Chris

chris wrote:I'm considering removing the temperature from the list of information displayed by Celestia. It's confusing to a lot of people, and isn't a fundamental datum.

--Chris

I'm not sure this is a good idea. At least, don't remove the temperature of stars !! This one is an important information !

Cham wrote:

chris wrote:I'm considering removing the temperature from the list of information displayed by Celestia. It's confusing to a lot of people, and isn't a fundamental datum.

--Chris

I'm not sure this is a good idea. At least, don't remove the temperature of stars !! This one is an important information !

No, I definitely will not remove the temperature of stars.

I should also point out that Hank's new scripting changes allow a great deal of flexibility in what information is displayed about planets.

--Chris

I think that having a rough estimate of black body temperature close to a planet is very usefull. Maybe you should just simplify the temperature calculation, by showing the star's radiation temperature at the planet position, without taking into consideration the albedo or any other effect.

It could just be labelled "Blackbody Temp" instead... but then yes, it would have to NOT include any albedo effects (ie treat the albedo as zero, so it absorbs all energy). That would be useful actually, you can use that to show where the Snow Lines are in systems.