The surface of Venus is over 900 degrees so I don't see how this is relevant. Yes, I know mercury it's closest to the sun. If bungie did a better job of explaining the story, you would know that the grimoire explains how the traveler made the other planets livable for humans. I mean c'mon man. It's a Sci-Fi game. How come when you jump on the moon gravity pulls you back down even though there's no atmosphere? Why can't I just float through the air infinitely?