Worldbuilding

2667 readers

21 users here now

Rules of !Worldbuilding:

See here for a longer, more explanatory version.

Rule 0: These are guidelines, not laws.
Rule 1: Be polite and respectful to others.
Rule 2: Provide some lore with your submissions!
Rule 3: Show some effort.
Rule 4: Do it yourself.
Rule 5: Advertising is limited.

Related Communities

For conlang (constructed languages) discussion check out !conlangs@mander.xyz Feel free to discuss the your conlangs in our community, as well!

founded 3 years ago

MODERATORS

infinitecartographer@lemmy.world

Gradually_Adjusting@lemmy.world

Zonetrooper@lemmy.world

Imotali@lemmy.world

How long do you think it would take the atmosphere to cool to the point of precipitating if the sun were to vanish? (lemmy.world)

submitted 1 day ago by early_riser@lemmy.world to c/worldbuilding@lemmy.world

7 comments fedilink hide all child comments

From what I remember, most (all?) of the heat in the atmosphere, or at least in the troposphere, comes from the ground, with convection carrying heat into the upper atmosphere.

Looking at my temperature graph from my weather station in my backyard, overnight the temp dropped about 1 Freedom Unit per hour. So at the absolute quickest, and assuming an average surface temperature of 60 F when the sun vanishes, here's what I have

Atmospheric gas	melting point (F)	hours until gas begins condensing	days until gas begins condensing
water	32	28	1.166666667
CO2	-70	130	5.416666667
argon	-307	367	15.29166667
N2	-346	406	16.91666667
O2	-361	421	17.54166667

This is likely way too fast, as I believe the colder you are, the less heat you lose. Also, melting/boiling points depend on the surrounding pressure, which will get effected by the other gases precipitating. 70 below isn't unheard of, and the coldest temp ever reached was -128 in Antarctica.

What do you think. IDK I'm le tired.

you are viewing a single comment's thread
view the rest of the comments

[–] zener_diode@feddit.org 2 points 19 hours ago (1 children)

This sounds to me like a question that could be answered using Universe Sandbox.

So, loading up the default solar system, here's Earth:

(note the temperature and gas pressure maps on the left)

Now, lets delete the Sun:

I'm setting the sim speed to 1 hour/second, so that I can see what's going on. Aaand hit play.

... it's much slower than I expected. I'm pretty sure the temperature sim was not meant for this, because after one simulated month, the average surface temperature has only dropped by about 2.5 °C. That sounds very wrong. (There is unfortunately no option to show the atmosphere's temperature.)

So ... the only significant difference is a slight temperature change, and (if you look at the liquid depth map) most of the northern hemisphere has been covered in a few millimeters to centimeters of liquid (maybe this is actually the atmosphere?). But gas pressure still looks mostly normal. Maybe I should file a bug report.

[–] early_riser@lemmy.world 2 points 19 hours ago (1 children)

That’s absolutely a bug. Temps dip more substantially even overnight. Assuming there’s no temperature advection during the night, the low is hit just before dawn. No dawn means no rising temperature.

[–] zener_diode@feddit.org 2 points 19 hours ago

Yeah, running it a bit longer (and much faster), it took a bit more than 150 years for the atmosphere to liquify.