ESC1000 – 88069; Earth Science
In the beginning the only planetary system that was known to man was our solar system made up of nine planets. At the time the major planets were Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. There were also many other minor planets in our solar system, but not as important compared to the major planets. On 24 August 2006, the International Astronomical Union (IAU) struck Pluto from the list of major planets, demoting it to the newly created category of “dwarf planet.” The move was spurred by the discovery of multiple large bodies orbiting even farther from the sun than distant Pluto, as a result of an object called Eris, which appeared to be bigger than Pluto.
As a result, the International Astronomical Union (IAU) define a planet as a celestial body that is in orbit around a star, nearly round in shape with sufficient mass, and an object that is clear around the orbit surrounding its neighborhood, and is not a satellite. As a result, the solar system now has eight planets…Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. They define a dwarf planet as a celestial body that orbits the Sun, is not a moon, not a satellite, has enough mass to assume a nearly round shape, and has not cleared the neighborhood around its orbit. Although, scientists believe there may be dozens or more dwarf planets in outer space, world only recognizes Pluto, Ceres, Eris, Makemake and Haumea. The difference between planets and dwarf planets is that planets have cleared the path around the sun while dwarf planets tend to orbit in zones of similar objects that can cross their path around the Sun. They both orbit the Sun not moons, must be large enough that their own gravity pulls them into the shapes of spheres ruling out numerous smaller bodies of asteroids. Another detail is that planets clear smaller objects out of their orbits by pulling the small bodies into themselves or throwing them out of orbit, while dwarf planets that have weaker gravities, are unable to clear out their orbits.
Although, scientists believe there may be dozens or more dwarf planets in outer space, National Aeronautics and Space Administration (NASA) acknowledges there are currently five official dwarf planets. Pluto, once the smallest of the nine “major” planets, became the first dwarf planet. Ceres, the largest asteroid in the main asteroid belt between Mars and Jupiter, also became the second dwarf planet. Finally, Eris, Makemake, and Haumea join the group to make of the starting five! Pluto, Makemake, and Haumea all orbit the Sun in the Kuiper Belt on the frozen edges of our Solar System. Eris, also called a Trans-Neptunian Object, is even further away from the Sun.
On February 18, 1930, Clyde W. Tombaugh, an assistant at the Lowell Observatory in Flagstaff, Arizona, discovered Pluto. Formerly the ninth planet from the sun,...