JohnWest — 2020-12-02 20:04:21 UTC A partially molten layer with a thickness of 93 miles (150 kilometers) surrounds the iron core. The finding implies the plumes are being fed by this vast liquid water reservoir. One of the most unusual KBOs is Haumea, which is a part of a collisional family orbiting the sun. Comets are generally named for their discoverer -- either a person or a spacecraft. Ceres is a good example of how challenging it can be to categorize bodies in our solar system. Based on the small number of craters observed, the surface of this moon appears to be no more than 40 to 90 million years old, which is quite youthful in geologic terms. It was the only way, he figured, to solve a baffling mystery about comets: Some comets loop through the solar system on periodic orbits of a half-dozen years or so. Asteroids range in size from Vesta - the largest at about 329 miles (530 kilometers) in diameter - to bodies that are less than 33 feet (10 meters) across. Enraged, Zeus struck the Titans with lightning. This is the case for Earth as well; craters on our planet are eroded by the relentless forces of flowing liquid (water, in Earth's case) and wind. The sun at the heart of our solar system is a yellow dwarf star, a hot ball of glowing gases. It takes icy Eris 557 Earth years to complete a single orbit around our sun. The changing illumination is why, from our perspective, the moon goes through phases. Triton's thin atmosphere, also discovered by Voyager, has been detected from Earth several times since, and is growing warmer - although scientists do not yet know why. It is the second least dense planet; Saturn is the least dense of all. They may yield important clues about the formation of our solar system. Venus' rotation and orbit are unusual in several ways. Its resonance with Dione excites its orbital eccentricity, which is damped by tidal forces, tidally heating its interior, and possibly driving the geological activity. Asteroids that actually cross Earth's orbital path are known as Earth-crossers. Uranus is also one of just two planets that rotate in the opposite direction than most of the planets (Venus is the other one), from east to west. Europa was abducted by Zeus (the Greek equivalent of the Roman god Jupiter), who had taken the shape of a spotless white bull. In 1991, astronomers on Earth using radar observations showed that Mercury may have water ice at its north and south poles inside deep craters. Like its fellow terrestrial planets, Venus has a central core, a rocky mantle and a solid crust. The next mission is Juno, which arrived in the Jovian system in July 2016. Our lunar neighbor has inspired stories since the first humans looked up at the sky and saw its grey, cratered face. Ceres has a very thin atmosphere, and there is evidence it contains water vapor. The chunks of ice and rock in Saturn's rings (and the particles in the rings of the other outer planets) are not considered moons, yet embedded in Saturn's rings are distinct moons or moonlets. That's much cooler than the blazing core, but it's still hot enough to make carbon, like diamonds and graphite, not just melt, but boil.