Portal:Solar System
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The Solar System consists of the Sun and the other celestial objects gravitationally bound to it: the eight planets, their 165 known moons, four currently identified dwarf planets (including Pluto) and their four known moons, and billions of small bodies. This last category includes asteroids, Kuiper belt objects, comets, meteoroids and interplanetary dust. In broad terms, the charted regions of the Solar System consist of the Sun, four terrestrial inner planets, an asteroid belt composed of small rocky bodies, four gas giant outer planets, and a second belt, called the Kuiper belt, composed of icy objects. Beyond the Kuiper belt lies the scattered disc, the heliopause, and ultimately the hypothetical Oort cloud. In order of their distances from the Sun, the planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Six of the eight planets are in turn orbited by natural satellites, usually termed "moons" after Earth's Moon, and each of the outer planets is encircled by planetary rings of dust and other particles. All the planets except Earth are named after gods and goddesses from Greco-Roman mythology. The four dwarf planets are Pluto and Makemake the two largest known Kuiper belt objects; Ceres, the largest object in the asteroid belt; and Eris, which lies in the scattered disc.
The Sun is composed of hydrogen (about 74% of its mass, or 92% of its volume), helium (about 25% of mass, 7% of volume), and trace quantities of other elements. The Sun has a spectral class of G2V. G2 implies that it has a surface temperature of approximately 5,500 K, giving it a white color which, because of atmospheric scattering, appears yellow as seen from the surface of the Earth. This is a subtractive effect, as the preferential scattering of blue photons (causing the sky color) removes enough blue light to leave a residual reddishness that is perceived as yellow.
Mars, the fourth planet from the Sun, is named after the Roman god of war because of its blood red color. Mars has two small, oddly-shaped moons, Phobos and Deimos, named after the sons of the Greek god Ares. At some point in the future Phobos will be broken up by gravitational forces. The atmosphere on Mars is 95% carbon dioxide. In 2003 methane was also discovered in the atmosphere. Since methane is an unstable gas, this indicates that there must be (or have been within the last few hundred years) a source of the gas on the planet.
- ...that New York's Panther Mountain (pictured) was the site of a prehistoric meteor crash?
- ...that the Beethoven crater in the Beethoven quadrangle on Mercury is the eleventh largest named impact crater in the Solar System?
- ...that the planet Mars appears red primarily because of a ubiquitous layer of dust containing nanophase ferric oxides?
- ...that the 1997 volcanic eruption of Pillan Patera on Jupiter's moon Io was the largest effusive eruption ever witnessed?
- ...that ridges and escarpments in the Victoria quadrangle of the planet Mercury have been associated with the stresses caused by the sun slowing Mercury's rotation through tidal forces?
- ...that J002E3 was at first thought to be a new moon of Earth when discovered in 2002 but was later found to be the third stage of the Apollo 12 Saturn V?
- ...that the Tooting impact crater on Mars was named after the London suburb of the same name because the discoverer "thought [his] mum and brother would get a kick out of having their home town paired with a land form on Mars"?
- ...that 99% of the mass of the Carme group, a group of retrograde irregular satellites of Jupiter, is located in Carme?
- ...that the Tolstoj crater, a 400-km (240 mile) wide impact crater on the planet Mercury has an extensive, and remarkably well-preserved, radially-lineated ejecta blanket?
- ...that Malin Space Science Systems operates the camera on the Mars Global Surveyor?
- ...that Abbott Lawrence Rotch established the Blue Hill Meteorological Observatory in 1885, which maintains the longest-running meteorological record of any observation site in the United States?
- ...that the asteroid 7796 Járacimrman, discovered in 1996 on Kleť Observatory and named after the famous fictitious Czech genius Jára Cimrman, proved to be the lost asteroid that had already been observed in 1973 on Brera-Merate Observatory in northern Italy?
- August 21: Iran tries to launch satellite with Safir carrier rocket
- August 14: Ariane 5 rocket launches Superbird 7 and AMC-21 satellites
- August 5: NASA denies rumors of finding life on Mars
- August 3: Falcon 1 rocket fails during third launch attempt
- August 1: NASA to extend the Phoenix probe mission by 5 weeks
- July 26: Kosmos-3M launches final SAR-Lupe satellite
- July 18: Searching for asteroids, extraterrestrial life a little more rocky: Budget cuts threaten to close Arecibo, world's largest radio telescope
- July 16: Zenit-3SL rocket launches Echostar XI satellite
- July 7: 40th Ariane 5 rocket launches ProtoStar-1 and Badr-6 satellites
- July 1: Ulysses spacecraft retires after 17 year mission
- June 27: Asteroid slammed into Mars' northern hemisphere
- June 27: Proton rocket launches Prognoz satellite
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wag1 ppl enjoy
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Solar System: Planets (Definition ˑ Planetary habitability ˑ Terrestrial planets ˑ Gas giants ˑ Rings) ˑ Dwarf planets (Plutoid) ˑ Moons ˑ Exploration ˑ Colonization ˑ Discovery timeline
- Sun: Sunspot ˑ Solar wind ˑ Solar flare ˑ Solar eclipse
- Mercury: Geology ˑ Exploration (Mariner 10 ˑ MESSENGER ˑ BepiColombo) ˑ Transit
- Venus: Geology ˑ Atmosphere ˑ Exploration (Venera ˑ Mariner program 2/5/10 ˑ Pioneer ˑ Vega 1/2ˑ Magellan ˑ Venus Express) ˑ Transit
- Earth: History ˑ Geology ˑ Geography ˑ Atmosphere ˑ Rotation
- Moon: Geology ˑ Selenography ˑ Atmosphere ˑ Exploration (Luna ˑ Apollo 8/11) ˑ Orbit ˑ Lunar eclipse
- Mars: Moons (Phobos ˑ Deimos) ˑ Geology ˑ Geography ˑ Atmosphere ˑ Exploration (Mariner ˑ Mars ˑ Viking 1/2 ˑ Pathfinder ˑ MER)
- Ceres: Exploration (Dawn)
- Jupiter: Moons (Amalthea, Io ˑ Europa ˑ Ganymede ˑ Callisto) ˑ Rings ˑ Great Red Spot ˑ Exploration (Pioneer 10/11 ˑ Voyager 1/2 ˑ Ulysses ˑ Cassini ˑ Galileo ˑ New Horizons)
- Saturn: Moons (Mimas ˑ Enceladus ˑ Tethys ˑ Dione ˑ Rhea ˑ Titan ˑ Iapetus) ˑ Rings ˑ Exploration (Pioneer 11 ˑ Voyager 1/2 ˑ Cassini–Huygens)
- Uranus: Moons (Miranda ˑ Ariel ˑ Umbriel ˑ Titania ˑ Oberon) ˑ Rings ˑ Exploration (Voyager 2)
- Neptune: Moons (Triton) ˑ Rings ˑ Exploration (Voyager 2)
- Pluto: Moons (Charon, Nix, Hydra) ˑ Exploration (New Horizons)
- Makemake
- Eris: Dysnomia
- Planets beyond Neptune
- Small bodies: Meteoroids ˑ Asteroids (Asteroid belt) ˑ Centaurs ˑ TNOs (Kuiper belt ˑ Scattered disc ˑ Oort cloud) ˑ Comets (Hale-Bopp ˑ Halley's ˑ Hyakutake ˑ Shoemaker-Levy 9)
- Formation and evolution of the Solar System: History of Solar System formation and evolution hypotheses ˑ Nebular hypothesis
- See Also: Featured content ˑ Featured topic ˑ Good articles ˑ List of objects
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