The Solar System

The Solar System The Solar System consists of the Sun and those celestial objects bound to it by gravity: the eight planets and five dwarf planets, their 173 known moons, and billions of small bodies. The small bodies include asteroids, icy Kuiper belt objects, comets, meteoroids, and interplanetary dust. The charted regions of the Solar System comprise the Sun, four terrestrial inner planets, the asteroid belt, four gas giant outer planets, and finally the Kuiper belt and the scattered disc. The hypothetical Oort cloud may also exist at a distance roughly a thousand times beyond these regions. The solar wind, a flow of plasma from the Sun, permeates the Solar System, creating a bubble in the interstellar medium known as the heliosphere, which extends out to the middle of the scattered disc. In order of their distances from the Sun, the eight planets are: Mercury (57,900,000 km) Venus (108,000,000 km) Earth (150,000,000 km) Mars (228,000,000 km) Jupiter (779,000,000 km) Saturn (1,430,000,000 km) Uranus (2,880,000,000 km) Neptune (4,500,000,000 km) As of mid-2008, five smaller objects are classified as dwarf planets, all but the first of which orbit beyond Neptune. These are: Ceres (415,000,000 km, in the asteroid belt; formerly classed as the fifth planet) Pluto (5,906,000,000 km, formerly classified as the ninth planet) Haumea (6,450,000,000 km) Makemake (6,850,000,000 km) Eris (10,100,000,000 km) Six of the planets and three of the dwarf planets are orbited by natural satellites, usually termed "moons" after Earth's Moon. Each of the outer planets is encircled by planetary rings of dust and other particles.   The Sun The Sun, an average-sized, middle-aged star, formed almost 5 billion years ago from a cloud of gas and dust.   Mercury Mercury, the closest planet to the Sun, takes only 88 days to orbit the Sun.   Venus The surface of Venus, the brightest object in the sky after the Sun and Moon, is covered with craters, mountains, volcanoes, and lava plains.   Earth Earth is the third planet from the Sun and takes 23 hours, 56 minutes to spin on its axis one time.   The Moon The Moon, located 238,000 miles from Earth, has a temperature of 225° F during the day and drops down to –243° at night.   Mars Rust in the soil creates the Red Planet's signature color.   Jupiter Jupiter is the largest planet in our solar system, with a diameter of 89,000 miles.   Saturn Saturn, the sixth planet from the Sun, has a ring system made up of ice and rock particles, some as big as a minivan.   Uranus Uranus, the third-largest planet in the solar system, has an average temperature of –350° F and does not have a solid surface.   Neptune Neptune has 13 moons, the two largest are Triton and Nereid.   Pluto Pluto, reclassified as a dwarf planet in 2006, is located nearly 40 times as far from the Sun as Earth.   Asteroids Asteroids, chunks of rock and metal that orbit the Sun, sometimes collide with the Earth. This is one possible explanation for the extinction of dinosaurs.   Comets Comets, thought to be leftovers of the early solar system, are made of dust, rocks, organic.   ©2009 Funspirations All Rights Reserved. Click here to Subscribe