Why is Earth's average temperature so low?

[ethan]

Hi;
I just installed the latest update to Universe Sandbox, and have been playing with it for a while.
I notice that when I first load the 'Solar System' sim, the average temperature of the Earth starts at around 7C, and drops from there as time passes.
Why would the temp start out so low (shouldn't it be around 15C?) and why would it go lower, and not higher - considering climate change.
But even if climate change is not worked into the calculations, I would expect the average temperature of Earth to start where it is today and remain relatively constant for thousands of years.

Am I doing something wrong?

Thanks
NJUltrarunner

[fiws]

I don't know if this is the same problem, but when i load the solar system all planets are at 0 Kelvin.
I also can't change the temp. It always just jumps back to 0 K.

[bshapiroalbert]

Thanks for asking about this. We recently became aware that the Earth's temperature is slightly lower than we would like it to be and decreases over time. We are looking into what change may have caused this and hope to have it fixed sometime in the future.

[bshapiroalbert]

Originally posted by fiws:

I don't know if this is the same problem, but when i load the solar system all planets are at 0 Kelvin.
I also can't change the temp. It always just jumps back to 0 K.

I'm sorry you're having this issue with Universe Sandbox. Are you running Universe Sandbox on a Linux machine?

We are aware that this issue sometimes occurs on Linux machines, and we have a temporary solution for it at this time.

Our temporary solution for this is to make sure that Vertical Sync is set to Off. You can do this by going to: Home > Settings > Graphics > Vertical Sync

You may need to restart Universe Sandbox after changing this setting for it to take effect.

Alternatively, you can try is running Universe Sandbox with Proton through Steam.

You can do this by right-clicking on Universe Sandbox in your Library, going to Compatibility, checking the "Force the use of a specific Steam Play compatibility tool" box, and selecting "Proton Experimental" from the dropdown list.

[fiws]

Originally posted by bshapiroalbert:

Our temporary solution for this is to make sure that Vertical Sync is set to Off. You can do this by going to: Home > Settings > Graphics > Vertical Sync

Thanks, this worked. (So ironically i need to heat the real earth, by rendering unneeded frames, to heat the earth in the game :D )

[bshapiroalbert]

Originally posted by Squid:

I'm on MacOS and I'm having similar problems. I just remade one of my simulations and on three terrestrial planets half of the hemispheres are 0 K for some reason. Still can't find out why

We recently pushed an update, 28.0.3, on October 8, 2021 that included a small fix to the Earth's average temperature. It should be stable around 13.8 degrees C now.

If you are still seeing issues like this with the most recent version of Universe Sandbox, it would be helpful if you could send us a copy of your log files as well as a saved simulation that shows this effect.

Here are some instructions for how to send your log files:
http://universesandbox.com/blog/2014/08/support-us2/#emaillog

And here are some instructions for how to send us your saved simulation:
http://universesandbox.com/blog/2014/08/support-us2/#emailsim

[Sanguinor]

Hello I'm on Windows 10 I've just bought universe sandbox on the 28 november 2021. The average temperature of Earth is still at around 8°C instead of 14°C. My vertical sync is desactivated but the earth temperature is too low.

[bshapiroalbert]

Thank you for your support and your question.

The default temperature that we show is the Surface Temperature, which changes based on the elevation and the Lapse Rate, the rate at which temperature drops with elevation on an object's surface. The average surface temperature is about 8.5 °C.

The average Sea Level temperature should still be around 14 °C. The Sea Level Temperature assumes that an object has a uniform elevation. You can find the Sea Level temperature under:
Properties > Surface > Sea Level

Hopefully that is helpful. We are constantly trying to improve Universe Sandbox to make this temperature simulation more accurate over time.

[Sanguinor]

Hello, Would it be possible to find, on the interface, the equivalent black body temperature of the planet ? https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature ?

[bshapiroalbert]

Yes, we call this the "Effective Temperature" in Universe Sandbox, and you can find it under:
Properties > Surface > Energy Flow > Effective Temperature

[Sanguinor]

Ok, I can use Effective Temperature (blackbody temperature) in °K but it is not the same number as in my equations. I don't know why. I have 275.92 °K and in the software it is 241 °K

World Type World Type 2 Atmo Pressure Atmo type atmosphéric Mass Atmosphéric Composition Toxicity Breathable Toxicity Corrosive Marginal Marginal description hydro % coverage Average Surface Temperature °K World Climate Table Average surface temperature °C blackbody correction blackbody temperature density World diameter in earth unit world surface gravity in earth unit World diameter in km World Mass in earth unit Ressources Habitability Affinity Star Luminosity in solar units Radius orbital in AU

Large Large (Garden) 3,85 Very Dense 0,7 "thick atmospheres
dominated by nitrogen and noble gases, with a significant amount of free oxygen" breathable (although it may be uncomfortably dense). Or marginal Breathable Unknown Not corrosive Marginal High Carbon Dioxide 80% 270°K Chilly -3,15°C 0,97856 275.92°K 1,1 1,13 1,243 14398,46 1,5871867 0,00 5 5,00 1 Sun 1,107329951AU

[bshapiroalbert]

I see that the Effective Temperature of Earth in the default Solar System simulation in Universe Sandbox fluctuates between 253 and 256 degrees Kelvin depending on where the Earth is in its orbit.

From a few different sources online, such as the one below, it seems that Earth's Equilibrium temperature is close to 260 degrees Kelvin.
https://www.astro.princeton.edu/~strauss/FRS113/writeup3/

It is possible that our Equilibrium Temperature is off by a couple of degrees due to rounding issues or other slightly different values of albedo, Sun temperature, or distance from the Sun. I am not sure what the difference is in your calculations unfortunately.

[Sanguinor]

This is what I use :

To determine the blackbody temperature,
divide the average surface temperature by the blackbody correction.

The blackbody correction
is based on two different factors, each
dependent on the world type and a
few other parameters: the absorption
factor and the greenhouse factor.

The absorption factor is a measure
of how much incoming energy is
absorbed by the world’s surface rather
than being reflected away. The higher
the absorption factor, the more energy
is absorbed, and the warmer the world
will be with respect to its blackbody
temperature. (For those familiar with
astrophysics, the absorption factor
can be determined by subtracting the
world’s albedo from one, and taking
the fourth root of the result.)

The greenhouse factor is a measure
of how much heat energy is trapped
by the world’s atmosphere rather than
being radiated back into space. The
higher the greenhouse factor, the
more energy is recycled within the
atmosphere, and the warmer the
world will be with respect to its blackbody
temperature.

[bshapiroalbert]

My guess is that the difference comes from limitations in the way we compute some of our heating sources in Universe Sandbox.

Some of our heating processes are simplified from real life due to computational limits or current limits of our simulation. For example, we do not have materials like carbon dioxide or nitrogen, which may affect our atmospheric heating computations compared to real life.

If you would like to learn more about how we compute these values, we have a wiki that describes how we compute Effective Temperature and the power from various sources of heating:
https://universesandbox.fandom.com/wiki/Temperature_Calculation#Equilibrium_and_Effective_Temperatures

[Sanguinor]

Thank you for the wiki link. The difference could come from the greenhouse effect that is in my calculus.

[CyberTiger]

What about surface temperature? I've noticed max temperatures range around 27°C max on Earth in game, is that correct, given some areas of Earth in reality have temperatures in excess of 40°C?