Portal:Solar System
The Solar System Portal
The Solar System is the gravitationally bound system of the Sun and the objects that orbit it. The largest of these objects are the eight planets, which in order from the Sun are four terrestrial planets (Mercury, Venus, Earth and Mars); two gas giants (Jupiter and Saturn); and two ice giants (Uranus and Neptune). The Solar System developed 4.6 billion years ago when a dense region of a molecular cloud collapsed, forming the Sun and a protoplanetary disc.
All four terrestrial planets belong to the inner Solar System and have solid surfaces. Inversely, all four giant planets belong to the outer Solar System and do not have a definite surface, as they are mainly composed of gases and liquids. 99.86% of the Solar System's mass is in the Sun and nearly 90% of the remaining mass are in Jupiter and Saturn. There is a strong consensus among astronomers that the Solar System also has nine dwarf planets, which consist of one asteroid-belt object – Ceres; five Kuiper-belt objects – Pluto, Orcus, Haumea, Quaoar, and Makemake; and three scattered-disc objects – Gonggong, Eris, and Sedna.
There are a vast number of smaller objects orbiting the Sun, called small Solar System bodies. This category includes asteroids, comets, centaurs, meteoroids and interplanetary dust clouds. Many of these objects are in the asteroid belt between the orbits of Mars and Jupiter (1.5–4.5 AU), and the Kuiper belt just outside Neptune's orbit (30–50 AU). Six of the major planets, the six largest possible dwarf planets, and many of the smaller bodies are orbited by natural satellites, commonly called "moons" after Earth's Moon. Two natural satellites, Jupiter's moon Ganymede and Saturn's moon Titan, are larger than Mercury, the smallest terrestrial planet, though they are less massive.
The Solar System is constantly flooded by the Sun's charged particles, the Solar wind, forming the heliosphere. Pushed against by the surrounding interstellar medium of the Local Cloud, the Solar wind starts slowing at 75 to 90 AU (the termination shock), before being halted, resulting in the heliopause, the boundary of the Solar System to interstellar space. The outermost region of the Solar System is the Oort cloud, the source for long-period comets, extending from 2,000 AU to the edge of the Solar System's sphere of gravitational influence at up to 200,000 AU (3.2 ly). The closest star to the Solar System, Proxima Centauri, is 4.25 ly away. The Solar System orbits the Galactic Center of the Milky Way galaxy, as part of its Orion Spur, at a distance of 26,000 ly. (Full article...)
Selected article –
Selected picture
General images
The following are images from various Solar System-related articles on Wikipedia.
Did you know –
- ... that Jupiter is the only planet capable of pulling an interstellar comet into a Sun-centered orbit?
- ...that the Solar Sentinels, a NASA spacecraft designed to study the Sun, will have to survive at distances from the Sun only one-quarter of Earth's distance?
- ...that just over 50 kilometres above its surface, the atmosphere of Venus has very similar pressure and temperature as does Earth, making it the most Earth-like area in the Solar System?
- ...that NASA conducts field trials, called Desert RATS, for new technologies for manned exploration of the surface of the Moon, Mars, or beyond?
- ...that scarps, ridges, and troughs, such as the 650 km long and 2 km high Discovery Rupes cutting through the Rameau crater, are common features in the Discovery quadrangle on the planet Mercury?
- ...that the Kármán line dividing the Earth's atmosphere and outer space is defined by the Fédération Aéronautique Internationale as 100 km above mean sea level?
- ...that Mars' south polar ice cap may be melting due to global warming?
- ...that Lowell Observatory staff resisted building the telescope used to discover the dwarf planet Pluto until trustee Roger Putnam ordered them to do so?
Categories
Solar System | ||
---|---|---|
Celestial mechanics | Comets | ...in fiction |
Minor planets | Moons | Planetary missions |
Planets... | Sun | Surface feature nomenclature... |
In the news
- 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) · Exploration (New Horizons)
- Haumea: Moons (Hi'iaka, Namaka)
- Makemake
- Eris: Dysnomia
- 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
|
Here are some tasks awaiting attention:
|
Related portals
Related WikiProjects
Solar System | Moon | Mars |
---|---|---|
Astronomy | Astronomical objects | Spaceflight |
Associated Wikimedia
The following Wikimedia Foundation sister projects provide more on this subject:
-
Commons
Free media repository -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikiversity
Free learning tools -
Wiktionary
Dictionary and thesaurus
-
List of all portals
-
Random portal
-
WikiProject Portals