Portal:Outer space
Portal maintenance status: (April 2019)
|
Introduction
Outer space (or simply space) is the expanse that exists beyond Earth's atmosphere and between celestial bodies. It contains ultra-low levels of particle densities, constituting a near-perfect vacuum of predominantly hydrogen and helium plasma, permeated by electromagnetic radiation, cosmic rays, neutrinos, magnetic fields and dust. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins (−270 °C; −455 °F).
The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe, having a number density of less than one hydrogen atom per cubic metre and a kinetic temperature of millions of kelvins. Local concentrations of matter have condensed into stars and galaxies. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems consist almost entirely of empty space. Most of the remaining mass-energy in the observable universe is made up of an unknown form, dubbed dark matter and dark energy.
Outer space does not begin at a definite altitude above Earth's surface. The Kármán line, an altitude of 100 km (62 mi) above sea level, is conventionally used as the start of outer space in space treaties and for aerospace records keeping. Certain portions of the upper stratosphere and the mesosphere are sometimes referred to as "near space". The framework for international space law was established by the Outer Space Treaty, which entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space. Despite the drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit.
The concept that the space between the Earth and the Moon must be a vacuum was first proposed in the 17th century after scientists discovered that air pressure decreased with altitude. The immense scale of outer space was grasped in the 20th century when the distance to the Andromeda galaxy was first measured. Humans began the physical exploration of space later in the same century with the advent of high-altitude balloon flights. This was followed by crewed rocket flights and, then, crewed Earth orbit, first achieved by Yuri Gagarin of the Soviet Union in 1961. The economic cost of putting objects, including humans, into space is very high, limiting human spaceflight to low Earth orbit and the Moon. On the other hand, uncrewed spacecraft have reached all of the known planets in the Solar System. Outer space represents a challenging environment for human exploration because of the hazards of vacuum and radiation. Microgravity has a negative effect on human physiology that causes both muscle atrophy and bone loss. (Full article...)
Selected article
Triton is the largest moon of the planet Neptune, discovered on October 10, 1846, by William Lassell. It is the only large moon in the Solar System with a retrograde orbit, which is an orbit in the opposite direction to its planet's rotation. At 2,700 km (1,700 mi) in diameter, it is the seventh-largest moon in the Solar System. Because of its retrograde orbit and composition similar to Pluto's, Triton is thought to have been captured from the Kuiper belt. Triton consists of a crust of frozen nitrogen over an icy mantle believed to cover a substantial core of rock and metal. The core makes up two-thirds of its total mass. Triton has a mean density of 2.061 g/cm3 (1.191 oz/cu in) and is composed of approximately 15–35% water ice. Triton is one of the few moons in the Solar System known to be geologically active. As a consequence, its surface is relatively young, with a complex geological history revealed in intricate and mysterious cryovolcanic and tectonic terrains. Part of its crust is dotted with geysers believed to erupt nitrogen.
Selected picture
-
Image 1Neptune is the eighth and farthest known planet from the Sun in the Solar System. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet and the densest giant planet. Neptune is 17 times the mass of Earth, slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. Neptune orbits the Sun once every 164.8 years at an average distance of 30.1 au (4.5 billion km; 2.8 billion mi). It is named after the Roman god of the sea and has the astronomical symbol ♆, a stylised version of the god Neptune's trident.
This picture of Neptune was taken by NASA's Voyager 2 spacecraft in 1989, at a range of 4.4 million miles (7.1 million kilometres) from the planet, approximately four days before closest approach. The photograph shows the Great Dark Spot, a storm about the size of Earth, in the centre, while the fast-moving bright feature nicknamed the "Scooter" and the Small Dark Spot can be seen on the western limb. These clouds were seen to persist for as long as the spacecraft's cameras could resolve them. -
Image 2A composite photo of the Orion Nebula, the closest region of star formation to Earth. It is composed of 520 separate images and NASA calls it "one of the most detailed astronomical images ever produced". The nebula is located below Orion's Belt and is visible to the naked eye at night. It is one of the most scrutinized and photographed objects in the night sky, and is among the most intensely-studied celestial features.
-
Image 3Photo: NASA/Crew of Expedition 22Space Shuttle Endeavour in a photograph taken from the International Space Station, in which the shuttle appears to straddle the stratosphere and mesosphere. During this mission, STS-130, the shuttle's primary payloads were the Tranquility module and the Cupola, a robotic control station which provides a 360-degree view around the station.
-
Image 4Credit: NASAThis Supernova remnant of Kepler's Supernova (SN 1604) is made up of the materials left behind by the gigantic explosion of a star. There are two possible routes to this end: either a massive star may cease to generate fusion energy in its core, and collapse inward under the force of its own gravity, or a white dwarf star may accumulate material from a companion star until it reaches a critical mass and undergoes a similar collapse. In either case, the resulting supernova explosion expels much or all of the stellar material with great force.
-
Image 5NASA astronaut Robert Curbeam (left) and European Space Agency (ESA) astronaut Christer Fuglesang participate in STS-116's first of three planned sessions of extra-vehicular activity (EVA) as construction resumes on the International Space Station. The landmasses depicted in the background are the South Island (left) and North Island (right) of New Zealand.
-
Image 6Credit: NASAExtra-vehicular activity (EVA) is work done by an astronaut away from the Earth and outside of his or her spacecraft. EVAs may be made outside a craft orbiting Earth (a spacewalk) or on the surface of the Moon (a moonwalk). Shown here is Steve Robinson on the first EVA to perform an in-flight repair of the Space Shuttle (August 3 2005).
-
Image 7Photograph credit: NASA / JPL / Space Science InstituteThe Cassini–Huygens space-research project involved a collaboration between NASA, the European Space Agency, and the Italian Space Agency to send a probe to study the planet Saturn and its system, including its rings and its natural satellites.
This natural-color mosaic image, combining thirty photographs, was taken by the Cassini orbiter over the course of approximately two hours on 23 July 2008 as it panned its wide-angle camera across Saturn and its ring system as the planet approached equinox. Six moons are pictured in the panorama, with the largest, Titan, visible at the bottom left. -
Image 8NGC 6357 is a diffuse nebula in the constellation Scorpius. This composite image of the nebula contains X-ray data from the Chandra X-ray Observatory and the ROSAT telescope (purple), infrared data from the Spitzer Space Telescope (orange), and optical data from the SuperCosmos Sky Survey (blue). Radiation from hot, young stars is energizing the cooler gas in the clouds that surround them. Often known as the Lobster Nebula, the astronomical object has also been termed the Madokami Nebula by fans of the anime Madoka Magica due to its supposed resemblance to the main character. Scientists at the Midcourse Space Experiment prefer the name War and Peace Nebula, because the bright, western part resembles a dove, while the eastern part looks like a skull in infrared images.
-
Image 9Credit: NASAMars, 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 10Credit: NASA, ESA, AURA/Caltech, Palomar ObservatoryThe Pleiades (also known as M45 or the Seven Sisters) is an open cluster in the constellation of Taurus. It is among the nearest to the Earth of all open clusters, probably the best known and certainly the most striking to the naked eye.
-
Image 11Diagram: Kelvin SongA 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 12Photo credit: Harrison SchmittAstronaut Eugene Cernan makes a short test drive of the lunar rover (officially, Lunar Roving Vehicle or LRV) during the early part of the first Apollo 17 extravehicular activity. The LRV was only used in the last three Apollo missions, but it performed without any major problems and allowed the astronauts to cover far more ground than in previous missions. All three LRVs were abandoned on the Moon.
-
Image 13The Pillars of Creation, a series of elephant trunks of interstellar gas and dust in the Eagle Nebula, are the subject of a famous Hubble Space Telescope photograph taken in 1995. They are so named because the depicted gas and dust, while being eroded by the light from nearby stars, are in the process of creating new stars. Shown here is a 2014 rephotograph, which was unveiled in 2015 as part of the telescope's 25th anniversary celebrations.
-
Image 14Photograph credit: European Space AgencyMars 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 15Photo credit: New Horizons probeAn animation of an eruption by the Tvashtar Paterae volcanic region on the innermost of Jupiter's Galilean moons, Io. The ejecta plume is 330 km (205 mi) high, though only its uppermost half is visible in this image, as its source lies over the moon's limb on its far side. This animation consists of a sequence of five images taken by NASA's New Horizons probe on March 1, 2007, over the course of eight minutes from 23:50 UTC.
-
Image 16Photo credit: NASAThe Eagle Nebula (also known as Messier Object 16, M16 or NGC 6611) is a young open cluster of stars. The nebula is an active region of star formation. Light from the bright, hot, young stars near the centre of the cluster illuminate the clouds of hydrogen gas and dust still collapsing to form new stars.
As projected on the sky, the Eagle Nebula lies in the constellation of Serpens Cauda. In three dimensions, it is relatively close to the Solar System being some 7,000 light years away on the edge of the Sagittarius Arm, the next nearest spiral arm towards the centre of the Milky Way.
In fact, when the picture is not coloured, is only red colored, the "Eagle" can be seen as a dark spot in the center of the nebula. -
Image 17Six beryllium mirror segments of the James Webb Space Telescope (JWST) undergoing a series of cryogenic tests at NASA's Marshall Space Flight Center in Huntsville, Alabama. The JWST is a planned space telescope that is a joint collaboration of 20 countries. It will orbit the Sun approximately 1,500,000 km (930,000 mi) beyond the Earth, around the L2 Lagrange point. It is expected to launch in December 2021.
-
Image 18The Day the Earth Smiled refers to the date July 19, 2013, on which the Cassini spacecraft turned to image Saturn, its entire ring system, and the Earth from a position where Saturn eclipsed the Sun. Cassini imaging team leader and planetary scientist Carolyn Porco called for all the world's people to reflect on humanity's place in the cosmos, to marvel at life on Earth, and to look up and smile in celebration. The final mosaic, shown here, was released four months later and includes planets Earth, Mars, and Venus, and a host of Saturnian moons.
-
Image 19A timed exposure of the first Space Shuttle mission, STS-1. The shuttle Columbia stands on launch pad A at Kennedy Space Center, the night before launch. The objectives of the maiden flight were to check out the overall Shuttle system, accomplish a safe ascent into orbit and to return to Earth for a safe landing.
-
Image 20The Pioneer plaque, which was included on both Pioneer 10 and Pioneer 11 unmanned spacecraft, the first man-made objects to leave the Solar System. Made from gold-anodised aluminium, the plaque shows the figures of a man and a woman along with several symbols that are designed to provide information about the origin of the spacecraft. However, the mean time for the spacecraft to come within 30 astronomical units of a star is longer than the current age of our galaxy.
-
Image 21Photo credit: Mars Reconnaissance OrbiterFalse-color Mars Reconnaissance Orbiter image of a side of the Chasma Boreale, a canyon in the polar ice cap of the Planum Boreum (north pole of Mars). Light browns are layers of surface dust, greys and blues are layers of water and carbon dioxide ice. Regular geometric cracking is indicative of higher concentrations of water ice.
The Planum Boreum's permanent ice cap has a maximum depth of 3 km (1.9 mi). It is roughly 1200 km (750 mi) in diameter, an area equivalent to about 1½ times the size of Texas. The Chasma Boreale is up to 100 km (62.5 mi) wide and features scarps up to 2 km (1.25 mi) high. For a comparison, the Grand Canyon is approximately 1.6 km (1 mi) deep in some places and 446 km (279 mi) long but only up to 24 km (15 mi) wide. -
Image 22A 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.
Space-related portals
General images
-
Image 1For the first time, the NASA / ESA / Canadian Space Agency / James Webb Space Telescope has observed the chemical signature of carbon-rich dust grains at redshift z ≈ 7, which is roughly equivalent to one billion years after the birth of the Universe, this observation suggests exciting avenues of investigation into both the production of cosmic dust and the earliest stellar populations in our Universe. (from Cosmic dust)
-
Image 2A dusty trail from the early Solar System to carbonaceous dust today. (from Cosmic dust)
-
Image 3Large-scale matter distribution in a cubic section of the universe. The blue fiber-like structures represent the matter, and the empty regions in between represent the cosmic voids of the intergalactic medium (from Outer space)
-
Image 6A micrometeoroid left this crater on the surface of Space Shuttle Challenger's front window on STS-7. (from Space debris)
-
Image 7Space Shuttle Endeavour had a major impact on its radiator during STS-118. The entry hole is about 5.5 mm (0.22 in), and the exit hole is twice as large. (from Space debris)
-
Image 8Cosmic dust of the Horsehead Nebula as revealed by the Hubble Space Telescope. (from Cosmic dust)
-
Image 9This light-year-long knot of interstellar gas and dust resembles a caterpillar. (from Interstellar medium)
-
Image 10A proposed timeline of the origin of space, from physical cosmology (from Outline of space science)
-
Image 11Voyager 1 is the first artificial object to reach the interstellar medium. (from Interstellar medium)
-
Image 12NASA computer-generated image of debris objects in Earth orbit, c. 2005. (from Space debris)
-
Image 13Earth and the Moon as seen from cislunar space on the 2022 Artemis 1 mission (from Outer space)
-
Image 14A MESSENGER image from 18,000 km showing a region about 500 km across (2008) (from Space exploration)
-
Image 15The diversity found in the different types and scales of astronomical objects make the field of study increasingly specialized. (from Outline of space science)
-
Image 16Perseverance's backshell sitting upright on the surface of Jezero Crater (from Space debris)
-
Image 17A computer-generated map of objects orbiting Earth, as of 2005. About 95% are debris, not working artificial satellites (from Outer space)
-
Image 18The Long Duration Exposure Facility (LDEF) is an important source of information on small-particle space debris. (from Space debris)
-
Image 20Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while outside their spacecraft.
-
Image 21Major elements of 200 stratospheric interplanetary dust particles. (from Cosmic dust)
-
Image 23Bow shock formed by the magnetosphere of the young star LL Orionis (center) as it collides with the Orion Nebula flow
-
Image 24Artist's impression of dust formation around a supernova explosion. (from Cosmic dust)
-
Image 27Conventional anti-satellite weapons such as the SM-3 missile remain legal under space law, even though they create hazardous space debris (from Outer space)
-
Image 29Artistic image of a rocket lifting from a Saturn moon (from Space exploration)
-
Image 30Known orbit planes of Fengyun-1C debris one month after the weather satellite's disintegration by the Chinese ASAT (from Space debris)
-
Image 32After reentry, Delta 2 second stage pieces were found in South Africa. (from Space debris)
-
Image 33A laser-guided observation of the Milky Way Galaxy at the Paranal Observatory in Chile in 2010 (from Outline of space science)
-
Image 34Growth of tracked objects in orbit and related events; efforts to manage outer space global commons have so far not reduced the debris or the growth of objects in orbit (from Space debris)
-
Image 35Gabbard diagram of almost 300 pieces of debris from the disintegration of the five-month-old third stage of the Chinese Long March 4 booster on 11 March 2000 (from Space debris)
-
Image 37Vanguard 1 is expected to remain in orbit for 240 years. (from Space debris)
-
Image 38Infographic showing the space debris situation in different kinds of orbits around Earth (from Space debris)
-
Image 39Spatial density of space debris by altitude according to ESA MASTER-2001, without debris from the Chinese ASAT and 2009 collision events (from Space debris)
-
Image 40Reconstruction of solar activity over 11,400 years. Period of equally high activity over 8,000 years ago marked. (from Space climate)
-
Image 41Map showing the Sun located near the edge of the Local Interstellar Cloud and Alpha Centauri about 4 light-years away in the neighboring G-Cloud complex (from Interstellar medium)
-
Image 42Smooth chondrite interplanetary dust particle. (from Cosmic dust)
-
Image 44Concept art for a NASA Vision mission (from Space exploration)
-
Image 46Model of Vostok spacecraft (from Space exploration)
-
Image 47Concept for a space-based solar power system to beam energy down to Earth (from Outer space)
-
Image 48Spent upper stage of a Delta II rocket, photographed by the XSS 10 satellite (from Space debris)
-
Image 49The distribution of ionized hydrogen (known by astronomers as H II from old spectroscopic terminology) in the parts of the Galactic interstellar medium visible from the Earth's northern hemisphere as observed with the Wisconsin Hα Mapper (Haffner et al. 2003) harv error: no target: CITEREFHaffnerReynoldsTufteMadsen2003 (help). (from Interstellar medium)
-
Image 50A wide field view of outer space as seen from Earth's surface at night. The interplanetary dust cloud is visible as the horizontal band of zodiacal light, including the false dawn (edges) and gegenschein (center), which is visually crossed by the Milky Way (from Outer space)
-
Image 51The 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.
-
Image 53Space debris identified as WT1190F, burning up in a fireball over Sri Lanka. (from Space debris)
-
Image 54Debris density in low Earth orbit (from Space debris)
-
Image 55Objects in Earth orbit including fragmentation debris, November 2020, NASA: ODPO (from Space debris)
-
Image 57View of an orbital debris hole made in the panel of the Solar Max satellite. (from Space debris)
-
Image 58Astronomers used the James Webb Space Telescope to image the warm dust around a nearby young star, Fomalhaut, in order to study the first asteroid belt ever seen outside of the Solar System in infrared light. (from Cosmic dust)
-
Image 59Apollo 16 LEM Orion, the Lunar Roving Vehicle and astronaut John Young (1972) (from Space exploration)
-
Image 60Buzz Aldrin taking a core sample of the Moon during the Apollo 11 mission (from Space exploration)
-
Image 62The original Magdeburg hemispheres (left) used to demonstrate Otto von Guericke's vacuum pump (right)
-
Image 63Illustration of a satellite breaking up into multiple pieces at higher altitudes. (from Space debris)
-
Image 64Apollo Command Service Module in lunar orbit (from Space exploration)
-
Image 66Near-Earth space showing the low-Earth (blue), medium Earth (green), and high Earth (red) orbits. The last extends beyond the radius of geosynchronous orbits (from Outer space)
-
Image 67Spatial density of LEO space debris by altitude, according to 2011 a NASA report to the United Nations Office for Outer Space Affairs (from Space debris)
-
Image 68A computer-generated animation by the European Space Agency representing space debris in low earth orbit at the current rate of growth compared to mitigation measures being taken. (from Space debris)
-
Image 69Debris impacts on Mir's solar panels degraded their performance. The damage is most noticeable on the panel on the right, which is facing the camera with a high degree of contrast. Extensive damage to the smaller panel below is due to impact with a Progress spacecraft. (from Space debris)
-
Image 70Astronaut Piers Sellers during the third spacewalk of STS-121, a demonstration of orbiter heat shield repair techniques (from Outline of space science)
-
Image 71Timeline of the expansion of the universe, where visible space is represented by the circular sections. At left, a dramatic expansion occurs in the inflationary epoch, and at the center, the expansion accelerates. Neither time nor size are to scale. (from Outer space)
-
Image 72First television image of Earth from space, taken by TIROS-1 (1960) (from Space exploration)
-
Image 74Astronaut Buzz Aldrin had a personal Communion service when he first arrived on the surface of the Moon. (from Space exploration)
-
Image 75Cosmic dust of the Andromeda Galaxy as revealed in infrared light by the Spitzer Space Telescope. (from Cosmic dust)
-
Image 76Atmospheric attenuation in dB/km as a function of frequency over the EHF band. Peaks in absorption at specific frequencies are a problem, due to atmosphere constituents such as water vapor (H2O) and carbon dioxide (CO2). (from Interstellar medium)
-
Image 77The International Space Station is an orbiting laboratory for space applications and habitability. Visible in the background is yellow-green airglow of Earth's ionosphere and the interstellar field of the Milky Way. (from Outer space)
-
Image 79Illustration of Earth's atmosphere gradual transition into outer space (from Outer space)
Did you know (auto-generated)
- ... that, for the Space 220 Restaurant, Disney reached out to NASA engineers to understand what a space elevator might look like?
- ... that some severe environmental impacts of the invasion of Ukraine can be seen from space?
- ... that the space industry of India has supported the launch of more than 100 domestic satellites and more than 300 foreign satellites?
- ... that Nature's Fynd, producer of microbe-based meat substitutes, is working with NASA to develop a bioreactor for use in space travel?
- ... that Louis W. Roberts was among the highest ranking African-American space program staff at NASA while the Apollo program was underway?
Space news
2024 in space | |||
---|---|---|---|
Space probe launches |
| ||
Impact events | |||
Selected NEOs | |||
Discoveries |
| ||
Comets | |||
Upcoming spaceflight launches
For a full schedule of launches and deep-space rendezvous, see 2024 in spaceflight.
|
Astronomical events
Topics
Biology |
| |||||
---|---|---|---|---|---|---|
Environment | ||||||
Society | ||||||
Technology |
| |||||
2020 in space | ||
---|---|---|
Space probe launches |
| |
Impact events | ||
Selected NEOs |
| |
Exoplanets |
| |
Discoveries |
| |
Comets | ||
Space exploration |
| |
2019 in space | ||
---|---|---|
Space probe launches |
| |
Impact events |
| |
Selected NEOs | ||
Exoplanets |
| |
Discoveries |
| |
Comets | ||
Space exploration |
| |
2018 in space | ||
---|---|---|
Space probe launches |
| |
Impact events | ||
Selected NEOs | ||
Exoplanets |
| |
Discoveries |
| |
Novae |
| |
Comets | ||
Space exploration |
| |
2017 in space | ||
---|---|---|
Space probe launches |
| |
Impact events | ||
Selected NEOs | ||
Exoplanets | ||
Discoveries | ||
Comets | ||
Space exploration |
| |
2016 in space | ||
---|---|---|
Space probe launches |
| |
Impact events | ||
Selected NEOs | ||
Exoplanets |
| |
Discoveries |
| |
Novae | ||
Comets | ||
Space exploration | ||
2015 in space | ||||||
---|---|---|---|---|---|---|
Space probe launches |
| |||||
Impact events | ||||||
Selected NEOs | ||||||
Exoplanets |
| |||||
Discoveries |
| |||||
Comets | ||||||
Space exploration | ||||||
Categories
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