1 00:00:00,000 --> 00:00:10,000 Our solar system is one of over 500 known solar systems in the entire Milky Way galaxy. 2 00:00:10,000 --> 00:00:18,000 The solar system came into being about 4.5 billion years ago when a cloud of interstellar gas and dust collapsed, 3 00:00:18,000 --> 00:00:26,000 resulting in a solar nebula, a swirling disk of material that collided to form the solar system. 4 00:00:26,000 --> 00:00:29,820 The solar system is located in the Milky Way's Orion star cluster. 5 00:00:30,539 --> 00:00:37,399 Only 15% of stars in the galaxy host planetary systems, and one of those stars is our own sun. 6 00:00:40,240 --> 00:00:42,840 Revolving around the sun are eight planets. 7 00:00:43,520 --> 00:00:48,899 The planets are divided into two categories based on their composition, terrestrial and jovian. 8 00:00:49,659 --> 00:00:55,579 Terrestrial planets, including Mercury, Venus, Earth, and Mars, are primarily made of rocky material. 9 00:00:55,579 --> 00:01:00,899 Their surfaces are solid, they don't have ring systems, they have very few or no 10 00:01:00,899 --> 00:01:07,719 moons, and they are relatively small. The smallest and closest to the Sun is 11 00:01:07,719 --> 00:01:11,859 Mercury which has the shortest orbit in the solar system at about three Earth 12 00:01:11,859 --> 00:01:18,500 months. Venus is the hottest planet with temperatures of up to 867 degrees 13 00:01:18,500 --> 00:01:23,379 Fahrenheit due to an atmosphere of carbon dioxide and extensive lava flows. 14 00:01:23,379 --> 00:01:28,359 Next to this world of fire is a world of water, Earth. 15 00:01:28,359 --> 00:01:32,659 The water systems on this planet help create the only known environment in the universe 16 00:01:32,659 --> 00:01:36,319 capable of sustaining life. 17 00:01:36,319 --> 00:01:42,500 The last of the terrestrial planets, Mars, might have also supported life about 3.7 billion 18 00:01:42,500 --> 00:01:48,980 years ago when the planet had a watery surface and moist atmosphere. 19 00:01:48,980 --> 00:01:53,299 Beyond the four terrestrial planets of the inner solar system lie the Jovian planets 20 00:01:53,299 --> 00:01:55,319 of the outer solar system. 21 00:01:55,319 --> 00:02:01,959 The Jovian planets include gas giants Jupiter and Saturn, and ice giants Uranus and Neptune. 22 00:02:01,959 --> 00:02:07,540 The gas giants are predominantly made of helium and hydrogen, and the ice giants also contain 23 00:02:07,540 --> 00:02:12,419 rock, ice, and a liquid mixture of water, methane, and ammonia. 24 00:02:12,419 --> 00:02:18,099 All four Jovian planets have multiple moons, sport ring systems, have no solid surface, 25 00:02:18,099 --> 00:02:20,979 and are immense. 26 00:02:20,979 --> 00:02:26,680 The largest Jovian is also the largest planet in the solar system, Jupiter. 27 00:02:26,680 --> 00:02:31,639 Nearby is Saturn, the solar system's second largest planet. 28 00:02:31,639 --> 00:02:36,300 Its signature rings are wide enough to fit between Earth and the moon, but are barely 29 00:02:36,300 --> 00:02:40,009 a kilometer thick. 30 00:02:40,009 --> 00:02:43,689 Past Saturn are the ice giants Uranus and Neptune. 31 00:02:43,689 --> 00:02:50,509 The slightly bigger of these ice giants, Uranus, is famous for rotating on its side. 32 00:02:50,509 --> 00:02:57,610 Next to Uranus is Neptune, the outermost planet in the solar system and also one of the coldest. 33 00:02:57,610 --> 00:03:02,770 Orbiting the terrestrial planets is the asteroid belt, a flat disk of rocky objects full of 34 00:03:02,770 --> 00:03:08,129 remnants from the solar system's formation, from microscopic dust particles to the largest 35 00:03:08,129 --> 00:03:12,669 known object, the dwarf planet Ceres. 36 00:03:12,669 --> 00:03:18,270 Another disk of space debris lies much further out and orbits the Jovian planets, the icy 37 00:03:18,270 --> 00:03:20,310 Kuiper Belt. 38 00:03:20,310 --> 00:03:25,349 Apart from asteroids, the Kuiper Belt is also home to dwarf planets such as Pluto and is 39 00:03:25,349 --> 00:03:28,069 the birthplace of many comets. 40 00:03:28,069 --> 00:03:33,830 Beyond the Kuiper Belt is the Oort Cloud, a vast, spherical collection of icy debris. 41 00:03:33,830 --> 00:03:38,389 It is considered the edge of the solar system since that is where the gravitational and 42 00:03:38,389 --> 00:03:42,030 physical influences of the Sun end. 43 00:03:42,030 --> 00:03:47,189 Our solar system's particular configuration of planets and other celestial objects, all 44 00:03:47,189 --> 00:03:56,430 revolving around a life-giving star make it a special place to call home.