These are some really interesting facts on space. Space is one of the most fascinating and interesting topics in itself. This article is full of information on this interesting topic. It snows in the upper atmosphere of Mars but vaporizes before reaching the ground. There was a time when Mars had large amounts of surface water. Proof of this facts have been fund on certain valleys and canyons. Saturn's rings are about 500,000 miles in circumference but only about a foot thick. December 21st 1968, was the first time that humans actually left the Earth, when Apollo 8 became the first manned space vehicle to leave Earth orbit and to orbit the Moon.