So what I’m reading is that these gas absorb the light from the sun and keeps it trapped on the earth.
What I don’t get is how is it letting the light and heat in from the sun in, but not the light and heat reflected from the Earth out? If it’s a barrier, shouldn’t it block both ways? If it’s not a barrier, how is it trapping the heat?
In: 950
The other commenters nailed the explanation but I’ll add that we can do a thing that’s like the greenhouse effect in reverse: [passive daytime radiative cooling](https://youtu.be/7a5NyUITbyk?t=170).
There’s a small window of IR (8000-13000 nm) that isn’t absorbed by the atmosphere, so if you engineer a material that absorbs/emits strongly in that range but not others, you can use all of space as a heat sink.
Stanford spun it out into a company called [SkyCool](https://www.skycoolsystems.com/#) in 2016.
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