Tycho Brahe's model of the solar system had the earth motionless and fixed at the center with the sun and stars moving around the earth, but he incorporated Copernicus' heliocentric model so that the other, non-Earth planets orbited around the sun. Brahe admired Copernicus' work and how it could explain the observed motion of planets, but he did not agree that the earth moved.
In 2 AD, Ptolemy developed a model of the solar system that had the earth at the center and the sun, planets and stars moving around the earth. Most observations seemed to validate this model, except for observations of the planets. Mars, in particular, could be observed to "wander," moving backward and then forward again at various points. Ptolemy and others tried to address the issue with epicycles, positing that Mars was in orbit around the earth but also in another smaller orbit around itself. The epicycles didn't work well mathematically, ultimately leading to Copernicus and his model with the sun at the center and the earth in orbit around it.
Tycho Brahe, who had developed very accurate instruments to measure planetary motion, did not believe the earth could also be in motion. His data suggested that the sun and stars orbited the earth, but like many others he found Ptolemy's epicycles problematic. By incorporating Copernicus' model of the planets orbiting the sun he felt he had addressed the mathematical issues surrounding epicycles while preserving the widely held belief that the earth was at the center of the solar system, and that all the heavenly bodies revolved around it.Learn More
Saturn's mass is 258,326,818,200,000,000,000,000,000 pounds (568,319,000,000,000,000,000,000,000 kilograms). The sixth planet in the solar system and the second largest after Jupiter, Saturn is about 886 million miles away from the Sun. According to the National Aeronautical and Space Authority, Saturn completes one rotation (spinning on its axis) in 10.70 Earth-hours.Full Answer >
According to University of California Santa Barbara ScienceLine, the world spins because it was formed from debris that was swirling around the Sun on a stable orbit. After the material clustered to form the Earth, the planet’s original motion was retained. Thus, the Earth maintains a stable orbit of fixed radius, in line with Kepler’s law and Newton’s laws.Full Answer >
Jupiter has rings. All four of the solar system's giant planets, Jupiter, Saturn, Uranus and Neptune, have rings. While the famous rings of Saturn, which are composed mainly of ice, are more pronounced, Jupiter's rings are relatively thin and are composed of dust.Full Answer >
Saturn's gases are about 96 percent hydrogen and 3 percent helium, with small amounts of ethane, methane, ammonia, propane and phosphine making up the rest of the atmosphere. Saturn is considered a gas giant, because much of it is made of gas.Full Answer >