Portal:Solar System

The Solar System Portal

The Sun and planets of the Solar System (distances not to scale)

The Solar System consists of the Sun and the objects that orbit it. The name comes from Sōl, the Latin name for the Sun. It formed about 4.6 billion years ago when a dense region of a molecular cloud collapsed, creating the Sun and a protoplanetary disc from which the orbiting bodies assembled. The fusion of hydrogen into helium inside the Sun's core releases energy, which is primarily emitted through its outer photosphere. This creates a decreasing temperature gradient across the system. Over 99.86% of the Solar System's mass is located within the Sun.

The most massive objects that orbit the Sun are the eight planets. Closest to the Sun in order of increasing distance are the four terrestrial planets – Mercury, Venus, Earth and Mars. Only the Earth and Mars orbit within the Sun's habitable zone, where liquid water can exist on the surface. Beyond the frost line at about five astronomical units (AU), are two gas giants – Jupiter and Saturn – and two ice giants – Uranus and Neptune. Jupiter and Saturn possess nearly 90% of the non-stellar mass of the Solar System.

There are a vast number of less massive objects. There is a strong consensus among astronomers that the Solar System has at least nine dwarf planets: Ceres, Orcus, Pluto, Haumea, Quaoar, Makemake, Gonggong, Eris, and Sedna. Six planets, seven dwarf planets, and other bodies have orbiting natural satellites, which are commonly called 'moons', and range from sizes of dwarf planets, like Earth's Moon, to moonlets. There are small Solar System bodies, such as asteroids, comets, centaurs, meteoroids, and interplanetary dust clouds. Some of these bodies are in the asteroid belt (between Mars's and Jupiter's orbit) and the Kuiper belt (just outside Neptune's orbit).

Between the bodies of the Solar System is an interplanetary medium of dust and particles. The Solar System is constantly flooded by outflowing charged particles from the solar wind, forming the heliosphere. At around 70–90 AU from the Sun, the solar wind is halted by the interstellar medium, resulting in the heliopause. This is the boundary to interstellar space. The Solar System extends beyond this boundary with its outermost region, the theorized Oort cloud, the source for long-period comets, extending to a radius of 2,000–200,000 AU. The Solar System currently moves through a cloud of interstellar medium called the Local Cloud. The closest star to the Solar System, Proxima Centauri, is 4.25 light-years (269,000 AU) away. Both are within the Local Bubble, a relatively small 1,000 light-years wide region of the Milky Way. (Full article...)

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The dwarf planet Ceres from the Dawn spacecraft
The dwarf planet Ceres from the Dawn spacecraft
A dwarf planet is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighbouring region of planetesimals and is not a satellite. They are smaller than planets, but more massive than small solar system bodies. The term was adopted in 2006 by the International Astronomical Union (IAU) as a result of the increase in discoveries of trans-Neptunian objects that rivaled Pluto in size, and finally precipitated by the discovery of an even more massive object, Eris. The IAU currently recognizes five dwarf planets—Ceres (pictured), Pluto, Haumea, Makemake, and Eris. It is suspected that at least another 40 known objects in the Solar System are dwarf planets, but the number might be as high as 2,000. The 2006 definition has been both praised and criticized, and has been disputed by some scientists. (Full article...)

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  • Image 1 Earthrise, as seen by Apollo 8 Apollo 8 Credit: William Anders Earthrise, the first occasion in which humans saw the Earth seemingly rising above the surface of the Moon, taken during the Apollo 8 mission on December 24, 1968. This view was seen by the crew at the beginning of its fourth orbit around the Moon, although the first photograph taken was in black-and-white. Note that the Earth is in shadow here. A photo of a fully lit Earth would not be taken until the Apollo 17 mission. '"`UNIQ--templatestyles-00000017-QINU`"' More selected pictures
    Earthrise, as seen by Apollo 8
    Earthrise, as seen by Apollo 8
    Earthrise, the first occasion in which humans saw the Earth seemingly rising above the surface of the Moon, taken during the Apollo 8 mission on December 24, 1968. This view was seen by the crew at the beginning of its fourth orbit around the Moon, although the first photograph taken was in black-and-white. Note that the Earth is in shadow here. A photo of a fully lit Earth would not be taken until the Apollo 17 mission.
  • Image 2 Mimas (moon) Photo: NASA/JPL/SSI Saturn's moon Mimas, as imaged by the Cassini spacecraft. It was discovered on 17 September 1789 by English astronomer William Herschel, and was named after Mimas, a son of Gaia in Greek mythology, by Herschel's son John. The large Herschel Crater is the dominating feature of the moon. With a diameter of 396 km (246 mi), it is the smallest astronomical body that is known to be rounded due to self-gravitation. More selected pictures
    Photo: NASA/JPL/SSI
    Saturn's moon Mimas, as imaged by the Cassini spacecraft. It was discovered on 17 September 1789 by English astronomer William Herschel, and was named after Mimas, a son of Gaia in Greek mythology, by Herschel's son John. The large Herschel Crater is the dominating feature of the moon. With a diameter of 396 km (246 mi), it is the smallest astronomical body that is known to be rounded due to self-gravitation.
  • Image 3 Jupiter Diagram: Kelvin Song A diagram of Jupiter showing a model of the planet's interior, with a rocky core overlaid by a deep layer of liquid metallic hydrogen and an outer layer predominantly of molecular hydrogen. Jupiter's true interior composition is uncertain. For instance, the core may have shrunk as convection currents of hot liquid metallic hydrogen mixed with the molten core and carried its contents to higher levels in the planetary interior. Furthermore, there is no clear physical boundary between the hydrogen layers—with increasing depth the gas increases smoothly in temperature and density, ultimately becoming liquid. More selected pictures
    Diagram: Kelvin Song
    A diagram of Jupiter showing a model of the planet's interior, with a rocky core overlaid by a deep layer of liquid metallic hydrogen and an outer layer predominantly of molecular hydrogen. Jupiter's true interior composition is uncertain. For instance, the core may have shrunk as convection currents of hot liquid metallic hydrogen mixed with the molten core and carried its contents to higher levels in the planetary interior. Furthermore, there is no clear physical boundary between the hydrogen layers—with increasing depth the gas increases smoothly in temperature and density, ultimately becoming liquid.
  • Image 4 Five global views of Venus by Magellan. Magellan (spacecraft) Credit: NASA/Jet Propulsion Laboratory These images are composites of the complete radar image collection obtained by the Magellan mission. The Magellan spacecraft was launched aboard Space Shuttle Atlantis in May 1989 and began mapping the surface of Venus in September 1990. The spacecraft continued to orbit Venus for four years, returning high-resolution images, altimetry, thermal emissions and gravity maps of 98 percent of the surface. Magellan spacecraft operations ended on October 12, 1994, when the radio contact was lost with the spacecraft during its controlled descent into the deeper portions of the Venusian atmosphere. '"`UNIQ--templatestyles-00000012-QINU`"' More selected pictures
    These images are composites of the complete radar image collection obtained by the Magellan mission. The Magellan spacecraft was launched aboard Space Shuttle Atlantis in May 1989 and began mapping the surface of Venus in September 1990. The spacecraft continued to orbit Venus for four years, returning high-resolution images, altimetry, thermal emissions and gravity maps of 98 percent of the surface. Magellan spacecraft operations ended on October 12, 1994, when the radio contact was lost with the spacecraft during its controlled descent into the deeper portions of the Venusian atmosphere.
  • Image 5 Lunar distance Model: Nickshanks Lunar distance is a measurement of the distance from the Earth to the Moon. This diagram shows the distance, averaging 384,400 km (238,900 mi), to scale, as well as the Earth and the Moon (scroll to see the entire image). More selected pictures
    Model: Nickshanks
    Lunar distance is a measurement of the distance from the Earth to the Moon. This diagram shows the distance, averaging 384,400 km (238,900 mi), to scale, as well as the Earth and the Moon (scroll to see the entire image).
  • Image 6 Jupiter Jupiter Credit: Cassini probe Jupiter is the fifth planet from the Sun and by far the largest within the Solar System. It is 318 times more massive than Earth, with a diameter 11 times that of Earth, and with a volume 1300 times that of Earth. Its best known feature is the Great Red Spot, a storm larger than Earth, which was first observed by Galileo four centuries ago. This picture, taken by the Cassini orbiter was one of 26 thousand images taken of Jupiter during the course of its flyby and is the most detailed global color portrait of the planet ever produced. '"`UNIQ--templatestyles-00000016-QINU`"' More selected pictures
    Jupiter
    Jupiter
    Jupiter is the fifth planet from the Sun and by far the largest within the Solar System. It is 318 times more massive than Earth, with a diameter 11 times that of Earth, and with a volume 1300 times that of Earth. Its best known feature is the Great Red Spot, a storm larger than Earth, which was first observed by Galileo four centuries ago. This picture, taken by the Cassini orbiter was one of 26 thousand images taken of Jupiter during the course of its flyby and is the most detailed global color portrait of the planet ever produced.
  • Image 7 Mars Mars Credit: NASA 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. '"`UNIQ--templatestyles-00000018-QINU`"' More selected pictures
    Mars
    Mars
    Credit: NASA
    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.
  • Image 8 Comet Hale-Bopp 29-03-1997 Comet Hale–Bopp Credit: Philipp Salzgeber Comet Hale–Bopp sails across the sky in the vicinity of Pazin in Istria, Croatia. To the lower right of the comet the Andromeda Galaxy is also faintly visible. The comet was visible to the naked eye for a record 18 months, twice as long as the Great Comet of 1811. At perihelion, it shone brighter than any star in the sky except Sirius, and its two tails stretched 30-40 degrees across the sky. The passage of Hale-Bopp was notable also for inciting a degree of panic about comets not seen for decades. Rumours that the comet was being followed by an alien spacecraft inspired a mass suicide among followers of the Heaven's Gate cult. '"`UNIQ--templatestyles-00000013-QINU`"' More selected pictures
    Comet Hale-Bopp 29-03-1997
    Comet Hale-Bopp 29-03-1997
    Credit: Philipp Salzgeber
    Comet Hale–Bopp sails across the sky in the vicinity of Pazin in Istria, Croatia. To the lower right of the comet the Andromeda Galaxy is also faintly visible. The comet was visible to the naked eye for a record 18 months, twice as long as the Great Comet of 1811. At perihelion, it shone brighter than any star in the sky except Sirius, and its two tails stretched 30-40 degrees across the sky. The passage of Hale-Bopp was notable also for inciting a degree of panic about comets not seen for decades. Rumours that the comet was being followed by an alien spacecraft inspired a mass suicide among followers of the Heaven's Gate cult.
  • Image 9 Sunspot TRACE image Sunspot Credit: NASA/TRACE A TRACE image of sunspots on the surface, or photosphere, of the Sun from September 2002, is taken in the far ultraviolet on a relatively quiet day for solar activity. However, the image still shows a large sunspot group visible as a bright area near the horizon. Although sunspots are relatively cool regions on the surface of the Sun, the bright glowing gas flowing around the sunspots have a temperature of over one million °C (1.8 million °F). The high temperatures are thought to be related to the rapidly changing magnetic field loops that channel solar plasma. '"`UNIQ--templatestyles-00000015-QINU`"' More selected pictures
    Sunspot TRACE image
    Sunspot TRACE image
    A TRACE image of sunspots on the surface, or photosphere, of the Sun from September 2002, is taken in the far ultraviolet on a relatively quiet day for solar activity. However, the image still shows a large sunspot group visible as a bright area near the horizon. Although sunspots are relatively cool regions on the surface of the Sun, the bright glowing gas flowing around the sunspots have a temperature of over one million °C (1.8 million °F). The high temperatures are thought to be related to the rapidly changing magnetic field loops that channel solar plasma.
  • Image 10 Saturn Photo credit: Cassini orbiter Saturn eclipsing the Sun, as seen by the Cassini orbiter. Individual rings seen in this image include (in order, starting from most distant): E ring, Pallene ring (visible very faintly in an arc just below Saturn), G ring, Janus/Epimetheus ring (faint), F ring (narrow brightest feature), Main rings (A,B,C), and D ring (bluish, nearest Saturn). Interior to the G ring and above the brighter main rings is the pale dot of Earth. More selected pictures
    Photo credit: Cassini orbiter
    Saturn eclipsing the Sun, as seen by the Cassini orbiter. Individual rings seen in this image include (in order, starting from most distant): E ring, Pallene ring (visible very faintly in an arc just below Saturn), G ring, Janus/Epimetheus ring (faint), F ring (narrow brightest feature), Main rings (A,B,C), and D ring (bluish, nearest Saturn). Interior to the G ring and above the brighter main rings is the pale dot of Earth.
  • Image 11 The Blue Marble Photo credit: The Apollo 17 crew The Blue Marble is a famous photograph of Earth. NASA officially credits the image to the entire Apollo 17 crew — Eugene Cernan, Ronald Evans and Jack Schmitt — all of whom took photographic images during the mission. Apollo 17 passed over Africa during daylight hours and Antarctica is also illuminated. The photograph was taken approximately five hours after the spacecraft's launch, while en route to the Moon. Apollo 17, notably, was the last manned lunar mission; no humans since have been at a range where taking a "whole-Earth" photograph such as "The Blue Marble" would be possible. More selected pictures
    Photo credit: The Apollo 17 crew
    The Blue Marble is a famous photograph of Earth. NASA officially credits the image to the entire Apollo 17 crew — Eugene Cernan, Ronald Evans and Jack Schmitt — all of whom took photographic images during the mission. Apollo 17 passed over Africa during daylight hours and Antarctica is also illuminated. The photograph was taken approximately five hours after the spacecraft's launch, while en route to the Moon. Apollo 17, notably, was the last manned lunar mission; no humans since have been at a range where taking a "whole-Earth" photograph such as "The Blue Marble" would be possible.
  • Image 12 Lunar phase Image: Tom Ruen An animation of the phases of the Moon. As the Moon revolves around the Earth, the Sun lights the Moon from a different side, creating the different phases. In the image, the Moon appears to get bigger as well as "wobble" slightly. Tidal locking synchronizes the Moon's rotation period on its axis to match its orbital period around the earth. These two periods nearly cancel each other out, except that the Moon's orbit is elliptical. This causes its orbital motion to speed up when closer to the Earth, and slow down when farther away, causing the Moon's apparent diameter to change, as well as the wobbling motion observed. More selected pictures
    Image: Tom Ruen
    An animation of the phases of the Moon. As the Moon revolves around the Earth, the Sun lights the Moon from a different side, creating the different phases. In the image, the Moon appears to get bigger as well as "wobble" slightly. Tidal locking synchronizes the Moon's rotation period on its axis to match its orbital period around the earth. These two periods nearly cancel each other out, except that the Moon's orbit is elliptical. This causes its orbital motion to speed up when closer to the Earth, and slow down when farther away, causing the Moon's apparent diameter to change, as well as the wobbling motion observed.
  • Image 13 Titan (moon) Image credit: Cassini orbiter The most detailed full-disc view of Titan, the largest moon of Saturn and second-largest in the Solar System. The brighter region on the right side and equatorial region is named Xanadu, and the large, dark region at the center is Shangri-la. This image has been processed to reduce the effects of the atmosphere and to sharpen surface features. It has been trimmed to show only the illuminated surface and not the atmosphere above the edge of the moon. More selected pictures
    Image credit: Cassini orbiter
    The most detailed full-disc view of Titan, the largest moon of Saturn and second-largest in the Solar System. The brighter region on the right side and equatorial region is named Xanadu, and the large, dark region at the center is Shangri-la. This image has been processed to reduce the effects of the atmosphere and to sharpen surface features. It has been trimmed to show only the illuminated surface and not the atmosphere above the edge of the moon.
  • Image 14 Mars Photograph credit: European Space Agency Mars is the fourth planet from the Sun and is known as the "Red Planet" due to its reddish appearance as seen from Earth. The planet is named after Mars, the Roman god of war. A terrestrial planet, Mars has a thin atmosphere and surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts and polar ice caps of the Earth. The planet has the highest mountain in the Solar System, Olympus Mons, as well as the largest canyon, Valles Marineris. Mars's rotation period and seasonal cycles are also similar to those of the Earth. Of all the planets in the Solar System other than Earth, Mars is the most likely to harbour liquid water and perhaps life. There are ongoing investigations assessing Mars's past potential for habitability, as well as the possibility of extant life. Future astrobiology missions are planned, including NASA's Mars 2020 rover and the European Space Agency (ESA)'s Rosalind Franklin rover. In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of the planet. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped. This picture is a true-colour image of Mars, taken from a distance of about 240,000 kilometres (150,000 mi) by the OSIRIS instrument on ESA's Rosetta spacecraft, during its February 2007 flyby of the planet. The image was generated using OSIRIS's orange (red), green and blue filters. More selected pictures
    Photograph credit: European Space Agency
    Mars is the fourth planet from the Sun and is known as the "Red Planet" due to its reddish appearance as seen from Earth. The planet is named after Mars, the Roman god of war. A terrestrial planet, Mars has a thin atmosphere and surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts and polar ice caps of the Earth. The planet has the highest mountain in the Solar System, Olympus Mons, as well as the largest canyon, Valles Marineris. Mars's rotation period and seasonal cycles are also similar to those of the Earth. Of all the planets in the Solar System other than Earth, Mars is the most likely to harbour liquid water and perhaps life. There are ongoing investigations assessing Mars's past potential for habitability, as well as the possibility of extant life. Future astrobiology missions are planned, including NASA's Mars 2020 rover and the European Space Agency (ESA)'s Rosalind Franklin rover. In November 2016, NASA reported finding a large amount of underground ice in the Utopia Planitia region of the planet. The volume of water detected has been estimated to be equivalent to the volume of water in Lake Superior. Mars has two moons, Phobos and Deimos, which are small and irregularly shaped.

    This picture is a true-colour image of Mars, taken from a distance of about 240,000 kilometres (150,000 mi) by the OSIRIS instrument on ESA's Rosetta spacecraft, during its February 2007 flyby of the planet. The image was generated using OSIRIS's orange (red), green and blue filters.
  • Image 15 Full moon Photo credit: Luc Viatour Full moon is a lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun, and when the three celestial bodies are aligned as closely as possible to a straight line. At this time, as seen by viewers on Earth, the hemisphere of the Moon that is facing the Earth (the near side) is fully illuminated by sunlight and appears round. Only during a full moon is the opposite hemisphere of the Moon, which is not visible from Earth (the far side), completely unilluminated. More selected pictures
    Photo credit: Luc Viatour
    Full moon is a lunar phase that occurs when the Moon is on the opposite side of the Earth from the Sun, and when the three celestial bodies are aligned as closely as possible to a straight line. At this time, as seen by viewers on Earth, the hemisphere of the Moon that is facing the Earth (the near side) is fully illuminated by sunlight and appears round. Only during a full moon is the opposite hemisphere of the Moon, which is not visible from Earth (the far side), completely unilluminated.
  • Image 16 Jupiter Image credit: NASA An animated view of Voyager I's approach to Jupiter. One frame of this image was taken each Jupiter day (approximately 10 hours) between January 6 and February 9, 1979, as the space probe flew from 58 million to 31 million kilometers from Jupiter during that time. The small, round, dark spots appearing in some frames are the shadows cast by the moons passing between Jupiter and the Sun, while the small, white flashes around the planet, are the moons themselves. More selected pictures
    Image credit: NASA
    An animated view of Voyager I's approach to Jupiter. One frame of this image was taken each Jupiter day (approximately 10 hours) between January 6 and February 9, 1979, as the space probe flew from 58 million to 31 million kilometers from Jupiter during that time. The small, round, dark spots appearing in some frames are the shadows cast by the moons passing between Jupiter and the Sun, while the small, white flashes around the planet, are the moons themselves.
  • Image 17 Hyperion Photo credit: Cassini orbiter Hyperion, a moon of Saturn, is one of the largest highly irregular (non-spherical) bodies in the Solar System. Enhanced image processing was used to bring out details and color differences in this photo taken by the Cassini orbiter. Hyperion is entirely saturated with deep, sharp-edged craters that give it the appearance of a giant sponge. Dark material fills the bottom of each crater. More selected pictures
    Photo credit: Cassini orbiter
    Hyperion, a moon of Saturn, is one of the largest highly irregular (non-spherical) bodies in the Solar System. Enhanced image processing was used to bring out details and color differences in this photo taken by the Cassini orbiter. Hyperion is entirely saturated with deep, sharp-edged craters that give it the appearance of a giant sponge. Dark material fills the bottom of each crater.
  • Image 18 Solar eclipse of 11 August 1999 Solar eclipse of 1999 August 11 Credit: Luc Viatour The solar eclipse of 1999 August 11, as seen from France. This was the most viewed total eclipse in human history, although some areas offered impaired visibility due to adverse weather conditions. The path of the Moon's shadow began in the Atlantic Ocean, before traversing Cornwall, northern France, southern Germany, Austria, Hungary and northern Serbia. Its maximum was in Romania, and it continued across the Black Sea, Turkey, Iran, southern Pakistan and India. '"`UNIQ--templatestyles-00000014-QINU`"' More selected pictures
    Solar eclipse of 11 August 1999
    Solar eclipse of 11 August 1999
    The solar eclipse of 1999 August 11, as seen from France. This was the most viewed total eclipse in human history, although some areas offered impaired visibility due to adverse weather conditions. The path of the Moon's shadow began in the Atlantic Ocean, before traversing Cornwall, northern France, southern Germany, Austria, Hungary and northern Serbia. Its maximum was in Romania, and it continued across the Black Sea, Turkey, Iran, southern Pakistan and India.
  • Image 19 Polar map of Jupiter Photo credit: Cassini orbiter This polar map of Jupiter, taken by the Cassini orbiter as it neared Jupiter during a flyby on its way to Saturn, is the most detailed global color map of the planet ever produced. The south pole is in the center of the map and the equator is at the edge. The map shows a variety of colorful cloud features, including parallel reddish-brown and white bands, the Great Red Spot, multi-lobed chaotic regions, white ovals, and many small vortexes. Many clouds appear in streaks and waves due to continual stretching and folding by Jupiter's winds and turbulence. More selected pictures
    Photo credit: Cassini orbiter
    This polar map of Jupiter, taken by the Cassini orbiter as it neared Jupiter during a flyby on its way to Saturn, is the most detailed global color map of the planet ever produced. The south pole is in the center of the map and the equator is at the edge. The map shows a variety of colorful cloud features, including parallel reddish-brown and white bands, the Great Red Spot, multi-lobed chaotic regions, white ovals, and many small vortexes. Many clouds appear in streaks and waves due to continual stretching and folding by Jupiter's winds and turbulence.
  • Image 20 Great Red Spot Photo credit: Voyager 1 False-color detail of Jupiter's atmosphere, imaged by Voyager 1, showing the Great Red Spot and a passing white oval. The wavy cloud pattern to the left of the Red Spot is a region of extraordinarily complex and variable wave motion. To give a sense of Jupiter's scale, the white oval storm directly below the Great Red Spot is approximately the same diameter as Earth. More selected pictures
    Photo credit: Voyager 1
    False-color detail of Jupiter's atmosphere, imaged by Voyager 1, showing the Great Red Spot and a passing white oval. The wavy cloud pattern to the left of the Red Spot is a region of extraordinarily complex and variable wave motion. To give a sense of Jupiter's scale, the white oval storm directly below the Great Red Spot is approximately the same diameter as Earth.
  • Image 21 Sun Diagram credit: Kelvin Ma The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear-fusion reactions in its core, radiating the energy mainly as visible light and infrared radiation. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometres (860,000 mi), or 109 times that of Earth. Its mass is about 330,000 times that of Earth, and accounts for about 99.86 percent of the total mass of the Solar System. Roughly three-quarters of the Sun's mass consists of hydrogen; the rest is mostly helium, with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron. This diagram illustrates the general structure of the Sun, with all features drawn to scale. More selected pictures
    Diagram credit: Kelvin Ma
    The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear-fusion reactions in its core, radiating the energy mainly as visible light and infrared radiation. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometres (860,000 mi), or 109 times that of Earth. Its mass is about 330,000 times that of Earth, and accounts for about 99.86 percent of the total mass of the Solar System. Roughly three-quarters of the Sun's mass consists of hydrogen; the rest is mostly helium, with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron. This diagram illustrates the general structure of the Sun, with all features drawn to scale.
  • Image 22 67P/Churyumov–Gerasimenko Photograph: ESA/Rosetta/NAVCAM A black-and-white photographic mosaic depicting the comet 67P/Churyumov–Gerasimenko, as photographed by the probe Rosetta. This Jupiter-family comet, which was originally from the Kuiper belt, is about 4.3 km (2.7 mi) across, has a current orbital period of 6.45 years, a rotation period of approximately 12.4 hours, and a maximum velocity of 135,000 km/h (38 km/s; 84,000 mph). It was first observed on photographic plates in 1969 by Soviet astronomers Klim Churyumov and Svetlana Gerasimenko, after whom it is named. More selected pictures
    Photograph: ESA/Rosetta/NAVCAM
    A black-and-white photographic mosaic depicting the comet 67P/Churyumov–Gerasimenko, as photographed by the probe Rosetta. This Jupiter-family comet, which was originally from the Kuiper belt, is about 4.3 km (2.7 mi) across, has a current orbital period of 6.45 years, a rotation period of approximately 12.4 hours, and a maximum velocity of 135,000 km/h (38 km/s; 84,000 mph). It was first observed on photographic plates in 1969 by Soviet astronomers Klim Churyumov and Svetlana Gerasimenko, after whom it is named.
  • Image 23 Tranquility Base Photograph credit: Neil Armstrong Tranquility Base is the landing site of the Apollo 11 mission on the Moon where, on July 20, 1969, humans first landed and walked on a celestial body other than the Earth. This photograph was taken at Tranquility Base by Neil Armstrong, the Apollo 11 commander, and depicts crewmember Buzz Aldrin with scientific equipment he had just deployed on the lunar surface. In the background on the right of the image is the lunar module, Eagle; the United States flag planted at the site during the mission was blown over the next day by the exhaust of the ascent rocket. More selected pictures
    Photograph credit: Neil Armstrong
    Tranquility Base is the landing site of the Apollo 11 mission on the Moon where, on July 20, 1969, humans first landed and walked on a celestial body other than the Earth. This photograph was taken at Tranquility Base by Neil Armstrong, the Apollo 11 commander, and depicts crewmember Buzz Aldrin with scientific equipment he had just deployed on the lunar surface. In the background on the right of the image is the lunar module, Eagle; the United States flag planted at the site during the mission was blown over the next day by the exhaust of the ascent rocket.

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Neptune: Moons (Triton) · Rings · Exploration (Voyager 2)
Planets beyond Neptune
Pluto: Moons (Charon, Nix, Hydra, Kerberos, Styx) · Geology · Atmosphere · Exploration (New Horizons)
Haumea: Moons (Hi'iaka, Namaka) · Ring
Quaoar: Weywot · Rings
Makemake: S/2015 (136472) 1
Gonggong: Xiangliu
Eris: Dysnomia
Sedna
Small bodies: Meteoroids · Asteroids (Asteroid belt) · Centaurs · TNOs (Kuiper belt · Scattered disc · Oort cloud) · Comets (Hale–Bopp · Halley's · Hyakutake · Shoemaker–Levy 9)
Formation and evolution of the Solar System: History of Solar System formation and evolution hypotheses · Nebular hypothesis
See also: Featured content · Featured topic · Good articles · List of objects

Bold articles are featured.
Italicized articles are on dwarf planets or major moons.

Things you can do

The planet Saturn, see here eclipsing the sun
The planet Saturn, see here eclipsing the sun
Here are some tasks awaiting attention:
  • Article requests : See Requested articles
  • Assess : To help us assess the quality and importance of Solar System articles, please see: Category:Unassessed Solar System articles and Category:Unknown-importance Solar System articles.
  • Expand : articles on the planets to help make them featured articles
  • Infobox : Solar System articles needing infoboxes
  • Maintain : Solar System articles needing attention
  • Photo : Wikipedia requested photographs of astronomical bodies
  • Stubs : Expand Solar System stub articles and Astronomy stub articles
  • Join : WikiProject Solar System and other WikiProjects related to this subject
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