80 upvotes, 4 direct replies (showing 4)
View submission: Why does it get cold at night ?
IR waves which are mostly transparent to the atmosphere remove all of the thermal energy. They just leave into space.
There is also a neat thing clouds do as they are a big factor in retaining heat at night. Water happens to not be transparent at the wavelength most IR waves escape as and as clouds it forms large absorption and reflection regions. CO2 is also not very transparent but as it doesn't form clouds on earth it is spread evenly in the atmosphere so it only determines how slowly the IR energy escapes.
Comment by redditonlygetsworse at 27/11/2024 at 22:42 UTC
69 upvotes, 2 direct replies
There is also a neat thing clouds do as they are a big factor in retaining heat at night.
Yeah anyone who has lived somewhere where it gets seriously cold knows that as nice as it is to see the sun in the winter, those clear skies also mean it's time to put on [even more] extra layers.
Comment by redpandaeater at 27/11/2024 at 22:57 UTC
11 upvotes, 0 direct replies
The water thing is also something people don't tend to talk about with global warming. Water isn't usually considered to have a significant global warming potential since its concentration isn't really affected by humans. It does however contribute up to potentially 2/3 of the entire greenhouse effect. Of course increasing temperatures increases the amount of water vapor in the air, which has a positive feedback effect.
Granted water can be fairly complicated since the albedo of clouds can help to reduce the amount of incoming solar radiation.
Comment by police-ical at 29/11/2024 at 00:18 UTC
2 upvotes, 0 direct replies
Incidentally, while we as warm-blooded animals are very sensitive to changes in air temperature, day-night swings are still quite small in terms of how much energy is there. An overnight fall from 60F to 40 F (about 15 to 4 C) sounds and feels like a lot, but in absolute terms it's only a fall from 289 to 278 K.
Comment by SolidOutcome at 28/11/2024 at 00:25 UTC
1 upvotes, 1 direct replies
If heat is readily emitted by IR only...then why is it so hard to cool things in space? Wouldn't everything cool rapidly into IR emissions?