Portal:Solar System

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The Solar System Portal

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

The Solar System is the gravitationally bound system of the Sun and the masses that orbit it, most prominently its eight planets, of which Earth is one. The system 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. Inside the Sun's core hydrogen is fused into helium for billions of years, releasing energy which is over even longer periods of time emitted through the Sun's outer layer, the photosphere. This creates the heliosphere and a decreasing temperature gradient across the Solar System.

The mass of the Solar System is by 99.86% almost completely made up of the Sun's mass. The next most massive objects of the system are the eight planets, which by definition dominate the orbits they occupy. Closest to the Sun in order of increasing distance are the four terrestrial planets – Mercury, Venus, Earth and Mars. These are the planets of the inner Solar System. Earth and Mars are the only planets in the Solar System which orbit within the Sun's habitable zone, in which the sunlight can make surface water under atmospheric pressure liquid. Beyond the frost line at about five astronomical units (AU), are two gas giants – Jupiter and Saturn – and two ice giants – Uranus and Neptune. These are the planets of the outer Solar System. Jupiter and Saturn possess nearly 90% of the non-stellar mass of the Solar System.

Additionally to the planets there are in the Solar System other planetary-mass objects, but which do not dominate their orbits, such as dwarf planets and planetary-mass moons. Dwarf planets there are generally nine Solar System objects identified as such: Ceres, Orcus, Pluto, Haumea, Quaoar, Makemake, Gonggong, Eris, and Sedna. Natural satellites, which are commonly called 'moons', can be found throughout the Solar System and in sizes from planetary-mass moons to much less massive moonlets at their smallest. The largest two moons (Ganymede of Jupiter and Titan of Saturn) are larger than the smallest planet (Mercury), while the seven most massive, which includes Earth's Moon, are more massive and larger than any of the dwarf planets. Less massive than these planetary-mass objects are the vast number of small Solar System bodies, such as asteroids, comets, centaurs, meteoroids, and interplanetary dust clouds. All dwarf planets and many of the smaller bodies are within the asteroid belt (between Mars's and Jupiter's orbit) and the Kuiper belt (just outside Neptune's orbit).

The Solar System is within the heliosphere constantly flooded by the charged plasma particles of the solar wind, which forms with the interplanetary dust, gas and cosmic rays between the bodies of the Solar System an interplanetary medium. At around 70–90 AU from the Sun, the solar wind is halted by the interstellar medium, resulting in the heliopause and the border of the interplanetary medium to interstellar space. Further out somewhere beyond 2,000 AU from the Sun extends the outermost region of the Solar System, the theorized Oort cloud, the source for long-period comets, stretching to the edge of the Solar System, the edge of its Hill sphere, at 178,000–227,000 AU (2.81–3.59 ly), where its gravitational potential becomes equal to the galactic potential. 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 269,000 AU (4.25 ly) away. Both are within the Local Bubble, a relatively small 1,000 light-years (ly) wide region of the Milky Way. (Full article...)

Selected article –

Mercury in color, taken by MESSENGER.

Mercury is the first planet from the Sun and the smallest in the Solar System. It is a rocky planet with a trace atmosphere and a surface gravity slightly higher than that of Mars. The surface of Mercury is similar to Earth's Moon, being heavily cratered, with an expansive rupes system generated from thrust faults, and bright ray systems, formed by ejecta. Its largest crater, Caloris Planitia, has a diameter of 1,550 km (960 mi), which is about one-third the diameter of the planet (4,880 km or 3,030 mi).

Being the most inferior orbiting planet, it always appears close to the sun in Earth's sky, either as a "morning star" or an "evening star". It is the planet with the highest delta-v required for travel from Earth, as well as to and from the other planets in the Solar System.

Mercury's sidereal year (88.0 Earth days) and sidereal day (58.65 Earth days) are in a 3:2 ratio, in a spin–orbit resonance. Consequently, one solar day (sunrise to sunrise) on Mercury lasts for around 176 Earth days: twice the planet's sidereal year. This means that one side of Mercury will remain in sunlight for one Mercurian year of 88 Earth days; while during the next orbit, that side will be in darkness all the time until the next sunrise after another 88 Earth days. Above the planet's surface is an extremely tenuous exosphere and a faint magnetic field just strong enough to deflect solar winds. Combined with its high orbital eccentricity, the planet's surface has widely varying sunlight intensity and temperature, with the equatorial regions ranging from −170 °C (−270 °F) at night to 420 °C (790 °F) during sunlight. Due to its very small axial tilt, the planet's poles are permanently shadowed. This strongly suggests that water ice could be present in the craters.

Like the other planets in the Solar System, Mercury formed approximately 4.5 billion years ago. There are many competing hypotheses about Mercury's origins and development, some of which incorporate collision with planetesimals and rock vaporization; as of the early 2020s, many broad details of Mercury's geological history are still under investigation or pending data from space probes. Its mantle is highly homogeneous, which suggests that Mercury had a magma ocean early in its history, like the Moon. According to current models, Mercury may have a solid silicate crust and mantle overlaying a solid outer core, a deeper liquid core layer, and a solid inner core. Mercury is expected to be destroyed, along with Venus, and possibly the Earth and the Moon, when the Sun becomes a Red Giant in approximately seven or eight billion years. (Full article...)

More selected articles

Selected picture

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  Pluto

  Photograph: NASA / Johns Hopkins University Applied Physics Laboratory / Southwest Research Institute

  Pluto is a dwarf planet in the Kuiper belt, a ring of bodies beyond Neptune. Discovered by Clyde Tombaugh in 1930, Pluto was originally considered to be the ninth planet from the Sun. Following the discovery of several objects of similar size in the Kuiper belt, its status as a planet was questioned, and in 2006 the International Astronomical Union (IAU) gave a definition of the term "planet" that excluded Pluto. The largest and second-most-massive known dwarf planet in the Solar System, Pluto is primarily made of ice and rock. It is relatively small, with a moderately eccentric and inclined orbit.
  
  This photograph of Pluto is a composite of four near-true color images taken by the New Horizons spacecraft in 2015. The most prominent feature in the image, the bright, youthful, nitrogen ice plains of Sputnik Planitia, the left lobe of heart-shaped Tombaugh Regio, is at right center. This contrasts with the darker, more cratered terrain of Cthulhu Macula at lower left.
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  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.
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  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.
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  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.
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  Sun

  Photograph credit: NASA/SDO

  The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of plasma, heated by nuclear fusion of hydrogen into helium in its core, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 1.39 million kilometres (860,000 miles) or 109 times that of Earth, while its mass is about 330,000 times that of Earth. It accounts for about 99.86% 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 false-color photograph of the Sun was taken by the Atmospheric Imaging Assembly instrument on NASA's Solar Dynamics Observatory (SDO) at a wavelength of 304 angstroms, in the extreme ultraviolet region of the electromagnetic spectrum.
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  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.
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  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.
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  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.
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  Climate of Mars

  Photograph credit: NASA / JPL–Caltech / University of Arizona

  Although Mars is smaller than the Earth and 50 percent farther from the Sun, its climate has important similarities with the Earth, such as the presence of polar ice caps, seasonal changes and observable weather patterns. This image shows layered deposits in Planum Boreum, in the north polar region of Mars, which formed from a 3-kilometre-thick (2 mi) stack of dusty water-ice layers about 1,000 km (600 mi) across. The layers record information about the climate of the planet stretching back several million years. Erosion has created scarps and troughs that expose the layering. The tan-colored layers are the dusty water ice of the polar layered deposits, however a section of bluish layers is visible below them. These bluish layers contain sand-sized rock fragments that likely formed a large polar dunefield before the overlying dusty ice was deposited. This photograph, depicting an area approximately 1.3 km (0.8 mi) across, was captured by the HiRISE camera on board NASA's Mars Reconnaissance Orbiter.
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  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.
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  Victoria Crater, Mars

  Photo credit: Mars Reconnaissance Orbiter

  Victoria Crater, an impact crater at Meridiani Planum, near the equator of Mars. The crater is approximately 800 meters (half a mile) in diameter. It has a distinctive scalloped shape to its rim, caused by erosion and downhill movement of crater wall material. Layered sedimentary rocks are exposed along the inner wall of the crater, and boulders that have fallen from the crater wall are visible on the crater floor. The floor of the crater is occupied by a striking field of sand dunes. The Mars rover Opportunity can be seen in this image, at roughly the "ten o'clock" position along the rim of the crater.
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  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.
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  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.
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  C/2014 Q2 (Lovejoy)

  Photograph: John Vermette

  C/2014 Q2 (Lovejoy) is a long-period comet discovered in 2014 by Australian astronomer Terry Lovejoy using a 0.2-meter (8 in) Schmidt–Cassegrain telescope. It was discovered at apparent magnitude 15 in the southern constellation of Puppis, and is the fifth comet discovered by Lovejoy. Its blue-green glow is the result of organic molecules and water released by the comet fluorescing under the harsh UV and optical light of the sun as it passes through space.
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  Pale Blue Dot

  Photo credit: NASA/JPL

  Pale Blue Dot is the name given to this 1990 photo of Earth taken from Voyager 1 when its vantage point reached the edge of the Solar System, a distance of roughly 3.7 billion miles (6 billion kilometres). Earth can be seen as a blueish-white speck approximately halfway down the brown band to the right. The light band over Earth is an artifact of sunlight scattering in the camera's lens, resulting from the small angle between Earth and the Sun. Carl Sagan came up with the idea of turning the spacecraft around to take a composite image of the Solar System. Six years later, he reflected, "All of human history has happened on that tiny pixel, which is our only home."
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  Comet McNaught

  Photo credit: Fir0002

  Comet C/2006 P1 (McNaught), as seen from Swifts Creek, Victoria, Australia. This non-periodic comet, the brightest in over 40 years, was discovered on August 7, 2006 by British-Australian astronomer Robert H. McNaught. It was first visible in the northern hemisphere, reaching perihelion on January 12, 2007 at a distance of 0.17 AU.
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  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.
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  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.
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  Geology of Venus

  Image credit: NASA

  A radar image of the surface of Venus, centered at 180 degrees east longitude. This composite image was created from mapping by the Magellan probe, supplemented by data gathered by the Pioneer orbiter, with simulated hues based on color images recorded by Venera 13 and 14. No probe has been able to survive more than a few hours on Venus's surface, which is completely obscured by clouds, because the atmospheric pressure is some 90 times that of the Earth's, and its surface temperature is around 450 °C (842 °F).
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  Rhea

  Photo credit: Cassini orbiter

  Rhea, at 1,528 kilometres (949 mi) across, is the second-largest moon of Saturn and the ninth largest moon in the Solar System. It was discovered in 1672 by Giovanni Domenico Cassini, who named it after the Titan Rhea of Greek mythology, "mother of the gods".
  
  The giant Tirawa impact basin is seen above and to the right of center. Tirawa, and another basin to its southwest, are both covered in impact craters, indicating they are quite ancient.
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  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.
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  Iapetus

  Photo credit: Cassini orbiter

  False-color mosaic shows the entire hemisphere of Iapetus (1,468 km or 912 mi across) visible from the Cassini orbiter on the outbound leg of its encounter with the two-toned moon of Saturn in September 2007. The central longitude of the trailing hemisphere is 24 degrees to the left of the image's center. It is hypothesized that the moon's two-toned nature is due to the sublimation of various ices evaporated from the warmer parts of the surface.
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  Lakes of methane on Titan

  Image credit: Cassini orbiter

  This false-color radar image taken by the Cassini orbiter provides convincing evidence for large bodies of liquid methane on Titan. Images taken during a fly-by of the moon on July 22, 2006 show more than 75 large bodies of liquid ranging in diameter from three to 70km (1.9 to 43.6 mi) in the moon's northern hemisphere. Intensity in this colorized image is proportional to how much radar brightness is returned. The lakes, darker than the surrounding terrain, are emphasized here by tinting regions of low backscatter in blue. Radar-brighter regions are shown in tan. Smallest details in this image are about 500 m (1,640 ft) across. On January 3, 2007, NASA announced that scientists have "definitive evidence of lakes filled with methane on Saturn's moon Titan."

General images

The following are images from various Solar System-related articles on Wikipedia.

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  Animations of the Solar System's outer planets orbiting. This animation is 100 times faster than the inner planet animation. (from Solar System)
• 
  An artist's impression of the Oort cloud, a region still well within the sphere of influence of the Solar System, including a depiction of the much further inside Kuiper belt (inset); the sizes of objects are over-scaled for visibility. (from Solar System)
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  The current Sun compared to its peak size in the red-giant phase (from Solar System)
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  The Solar System (left) within the interstellar medium, with the different regions and their distances on a logarithmic scale (from Solar System)
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  Diagram of the Milky Way, with galactic features and the relative position of the Solar System labeled. (from Solar System)
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  Meteor Crater in Arizona. Created 50,000 years ago by an impactor about 50 metres (160 ft) across, it shows that the accretion of the Solar System is not over. (from Formation and evolution of the Solar System)
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  Animations of the Solar System's inner planets orbiting. Each frame represents 2 days of motion. (from Solar System)
• 
  Simulation showing outer planets and Kuiper belt:
  a) Before Jupiter/Saturn 2:1 resonance
  b) Scattering of Kuiper belt objects into the Solar System after the orbital shift of Neptune
  c) After ejection of Kuiper belt bodies by Jupiter
  

    Orbit of Jupiter

    Orbit of Saturn

    Orbit of Uranus

    Orbit of Neptune

  (from Formation and evolution of the Solar System)
• 
  All active Solar System space probes in 2024 (and a list of upcoming ones) (from Solar System)
• 
  Neptune and its moon Triton, taken by Voyager 2. Triton's orbit will eventually take it within Neptune's Roche limit, tearing it apart and possibly forming a new ring system. (from Formation and evolution of the Solar System)
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  The planets, zodiacal light and meteor shower (top left of image) (from Solar System)
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  Solar system diagram by Emanuel Bowen in 1747, when neither Uranus, Neptune, nor the asteroid belts had yet been discovered. Orbits of planets are to scale, but the orbits of moons and the sizes of bodies are not. (from Solar System)
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  The sparse plasma (blue) and dust (white) in the tail of comet Hale–Bopp are being shaped by pressure from solar radiation and the solar wind, respectively.
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  Overview of the inner Solar System up to Jupiter's orbit (from Solar System)
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  Diagram of the Local Interstellar Cloud, the G-Cloud and surrounding stars. As of 2022, the exact position of the Solar System within the interstellar clouds remains an unresolved question in astronomy. (from Solar System)
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  The Sun in true white color (from Solar System)
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  The four largest asteroids: Ceres, Vesta, Pallas, Hygiea. Only Ceres and Vesta have been visited by a spacecraft and thus have a detailed picture. (from Solar System)
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  Comparison of the distances between planets, with the white bar showing orbital variations. The size of the planets is not to scale. (from Solar System)
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  Pierre-Simon Laplace, one of the originators of the nebular hypothesis (from Formation and evolution of the Solar System)
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  The Ring Nebula, a planetary nebula similar to what the Sun will become (from Formation and evolution of the Solar System)
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  Artist's conception of the giant impact thought to have formed the Moon (from Formation and evolution of the Solar System)
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  Orbit classification of Kuiper belt objects. Some clusters that is subjected to orbital resonance are marked. (from Solar System)
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  The motion of 'lights' moving across the sky is the basis of the classical definition of planets: wandering stars. (from Solar System)
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  A color enhanced photograph from the Moon of a range of components of the Solar System. The three dots at the lower left are from left to right the planets Saturn, Mars, and Mercury, and in the middle of the picture rises the Sun's corona over the dark limb of the Moon, which is from the right lit by earthshine. (from Solar System)
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  The current orbits of Sedna, 2012 VP113, Leleākūhonua (pink), and other very distant objects (red, brown and cyan) along with the predicted orbit of the hypothetical Planet Nine (dark blue) (from Solar System)
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  The outer planets Jupiter, Saturn, Uranus and Neptune, compared to the inner planets Earth, Venus, Mars, and Mercury at the bottom right (from Solar System)
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  The orbital eccentricities and inclinations of the scattered disc population compared to the classical and resonant Kuiper belt objects (from Solar System)
• 
  Hubble image of protoplanetary discs in the Orion Nebula, a stellar nursery approximately 25 ly across and estimated to be similar to the primordial nebula from which the Sun formed (from Formation and evolution of the Solar System)
• 
  Relative orbital distances in the Solar System visualized as a condensed rectangle (from Solar System)
• 
  Diagram of the Sun's magnetosphere and helioshealth (from Solar System)
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  Plot of objects around the Kuiper belt and other asteroid populations. J, S, U and N denotes Jupiter, Saturn, Uranus and Neptune. (from Solar System)
• 
  Diagram of the early Solar System's protoplanetary disk, out of which Earth and other Solar System bodies formed (from Solar System)
• 
  The four terrestrial planets Mercury, Venus, Earth and Mars (from Solar System)
• 
  Relative size of the Sun as it is now (inset) compared to its estimated future size as a red giant (from Formation and evolution of the Solar System)
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  Location of the Solar System within the Milky Way (from Formation and evolution of the Solar System)
• 
  Artist's conception of a protoplanetary disk (from Formation and evolution of the Solar System)

Did you know –

• ...that the passing of the Great Comet of 1577 (pictured) caused almost century-long debate, during which Galileo argued that comets were merely optical illusions?

• ...that systematic mapping of the Michelangelo quadrangle on Mercury has revealed the presence of four nearly obliterated multi-ring impact basins, possibly the oldest features in the mapped areas of the planet?

• ...that there have been several proposals for space advertising projects, including a giant, 1km² billboard visible from Earth?

• ...that some astrologers claim Earth has a second moon they call Lilith?

• ...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?

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In the news

Wikinews Space portal

• April 7: NASA's helicopter Ingenuity survives its first night at Mars
• December 25: 'Earth-based life can survive in hydrogen-rich atmospheres': MIT professor Dr Seager tells Wikinews about her research on organisms thriving in oxygen-less environment
• July 7: Astronomer Anthony Boccaletti discusses observation of birth of potential exoplanet with Wikinews
• May 31: SpaceX successfully launches its first crewed spaceflight
• May 22: Astronomer tells Wikinews about discovery of closest black hole known so far
• October 12: Cosmonaut Alexei Leonov dies at age 85
• October 10: Swedish academy announces 2019 Nobel Prize winners in physics
• September 14: Astronomers find water vapour in atmosphere of exoplanet K2-18b
• March 5: SpaceX Crew Dragon capsule docks with International Space Station
• January 9: Simple animals could live in Martian brines: Wikinews interviews planetary scientist Vlada Stamenković
• November 29: NASA's InSight Lander makes it to Mars
• October 12: Manned Soyuz space mission aborts during launch

Major topics

Solar System: Planets (Definition · Planetary habitability · Terrestrial planets · Gas giants · Rings) · Dwarf planets (Plutoid) · Colonization · Discovery timelineˑ Exploration · Moons · Planetariums

Sun: Sunspot · Solar wind · Solar flare · Solar eclipse

Mercury: Geology · Exploration (Mariner 10 · MESSENGER · BepiColombo) · Transit

Venus: Geology · Atmosphere · Exploration (Venera · Mariner program 2/5/10 · Pioneer · Vega 1/2ˑ Magellan · Venus Express) · Transit

Earth: History · Geology · Geography · Atmosphere · Rotation

Moon: Geology · Selenography · Atmosphere · Exploration (Luna · Apollo 8/11) · Orbit · Lunar eclipse

Mars: Moons (Phobos · Deimos) · Geology · Geography · Atmosphere · Exploration (Mariner · Mars · Viking 1/2 · Pathfinder · MER)

Ceres: Exploration (Dawn)

Jupiter: Moons (Amalthea, Io · Europa · Ganymede · Callisto) · Rings · Atmosphere · Magnetosphere · Exploration (Pioneer 10/11 · Voyager 1/2 · Ulysses · Cassini · Galileo · New Horizons)

Saturn: Moons (Mimas · Enceladus · Tethys · Dione · Rhea · Titan · Iapetus) · Rings · Exploration (Pioneer 11 · Voyager 1/2 · Cassini–Huygens)

Uranus: Moons (Miranda · Ariel · Umbriel · Titania · Oberon) · Rings · Exploration (Voyager 2)

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

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Italicized articles are on dwarf planets or major moons.

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The planet Saturn, see here eclipsing the sun

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