Why is the greenhouse effect only one way?

Question

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

Answer 1

Visible light goes through glass very easily, but heat goes through glass more slowly. That’s how actual greenhouses work.

Visible light goes through carbon dioxide very easily, but heat goes through carbon dioxide more slowly. That’s how the greenhouse effect works. Visible light hits the ground/ocean, warms it up, but the heat generated doesn’t escape because too much CO2 in the atmosphere.