Would a planet with the same atmosphere as Venus at Mars distance from the Sun still be hot?
I used to ponder this question too. If we were to swap over Venus and Mars, I think Venus would cool down significantly. It would be twice the distance from the sun, so would receive a quarter the heat input. It’s atmosphere would cool and become denser at the surface. The cloud deck would move lower to the planet’s surface. I suspect that the insulating properties of the dense atmosphere would still keep the surface well above the boiling point of water though. However, venus would never become Earth-like because it’s atmosphere is mostly co2, and most of the hydrogen needed to form water has either disappeared into space or become locked in the h2so4 that makes up the clouds.
