**Ask a monkey a physics question thread**

[BananaStand]

So my 8 year old educated me this week. Turns out that the hot-ness of a planet is not entirely correlated with its proximity to the sun. She had to do a little project on Venus and it turns out that's the hottest planet.

Seems odd that Mercury, which millions of miles closer to a massive fireball burning at about a jillion degrees Fahrenheit would be less hot.

Initial research suggest that the reason for this is Venus's very thick atmosphere that retains heat. But if that's the case....wouldn't Venus have just incinerated itself? Or is that actually what's happening...it' just takes a long time? Is venus burning up?

[OngBonga]

Another point to consider is that heat doesn't travel through space like it does through air. We feel warmth from the sun because of radiation, not because of convection.

I'm not 100% sure on this, but I think the light intensity at Venus is 4x weaker than Mercury (being twice the distance, inverse square law, 2 squared is 4). But when you consider heat moving through a fluid in a gravity field, well now most of the heat is going up, so you'll get much less than a quarter of the heat at twice the distance, unless you're above the heat source, in which case you'll get much more than a quarter.

Electromagnetic radiation travelling through space doesn't have this problem.