[Tycho?]

The Sun constitues over 99% of the mass of the entire solar system. Mercury is the only planet with no moons. While Mercury is the closest planet to the sun, Venus has the highest average temperature due to its runaway greenhouse effect. The tallest (known) mountain in the Solar System is Mons Olympus on Mars. The diameter of Jupiter is equivilant to the diameter of 11 Earths stacked on eachother. Saturn's moon titan has an atmosphere far thicker than Earth's and is composed mostly of nitrogen and methane The rotational axis of Uranus is tilted almost 90 degrees; its south pole points towards the sun. Neptune's moon Triton is the coldest body yet obvserved in the solar system. Pluto has a moon, Charon, which is more than half the diameter of Pluto itself.