Portal:Outer space
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Introduction
Outer space (or simply space) is the expanse beyond celestial bodies and their atmospheres. 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
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter, with an average radius about nine times larger than the Earth's. Saturn is named after the Roman god Saturn, equated to the Greek Cronus (the Titan father of Zeus), the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol (♄) represents the Roman god's sickle. Along with Jupiter, Uranus and Neptune, Saturn is a gas giant. Together, these four planets are sometimes referred to as the Jovian planets, meaning "Jupiter-like". Saturn has a ring system that is divided into nine continuous and three discontinuous main rings (arcs), consisting mostly of ice particles with a smaller amount of rocky debris and dust. Sixty-two known moons orbit the planet; fifty-three are officially named. This does not include the hundreds of "moonlets" within the rings. Titan, Saturn's largest and the Solar System's second largest moon (after Jupiter's Ganymede), is larger than the planet Mercury and is the only moon in the Solar System to retain a significant atmosphere.
Selected picture
- Image 1A solar flare, a sudden flash of brightness observed over the Sun's surface or the solar limb which is interpreted as a large energy release, recorded on August 31, 2012. Such flares are often, but not always, followed by a colossal coronal mass ejection; in this instance, the ejection traveled at over 900 miles (1,400 km) per second.
- Image 2The launch of Space Shuttle Atlantis on STS-98, February 7 2001, at sunset. The sun is behind the camera, and the shape of the plume is cast across the vault of the sky, intersecting the rising full moon. The top portion of the plume is bright because it is illuminated directly by the sun; the lower portions are in the Earth's shadow. After launch, the shuttle must engage in a pitch and roll program so that the vehicle is below the external tank and SRBs, as evidenced in the plume trail. The vehicle climbs in a progressively flattening arc, because achieving low orbit requires much more horizontal than vertical acceleration.
- Image 3NGC 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 4"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 5A Manned Maneuvering Unit (MMU) is a jet pack (propulsion backpack that snaps onto the back of the space suit) which has been used on untethered spacewalks from NASA's Space Shuttle, allowing an astronaut to move independently from the shuttle. The MMU was used on three Shuttle missions in 1984. It was first tested on February 7 during mission STS-41-B by astronauts Bruce McCandless II (seen here) and Robert L. Stewart.
- Image 6Image credit: United States Geological SurveyA composite image of Olympus Mons on Mars, the tallest known volcano and mountain in the Solar System. This image was created from black-and-white imagery from the USGS's Mars Global Digital Image Mosaic and color imagery acquired from the 1978 visit of Viking 1.
- Image 7Photo 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 8A 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 9"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 very 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 10The 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 11Image credit: SeavAn animated image showing the apparent retrograde motion of Mars in 2003 as seen from Earth. All the true planets appear to periodically switch direction as they cross the sky. Because Earth completes its orbit in a shorter period of time than the planets outside its orbit, we periodically overtake them, like a faster car on a multi-lane highway. When this occurs, the planet will first appear to stop its eastward drift, and then drift back toward the west. Then, as Earth swings past the planet in its orbit, it appears to resume its normal motion west to east.
- Image 12Realistic-color mosaic of images of Jupiter's moon Europa taken by NASA's Jupiter orbiter Galileo in 1995 and 1998. This view of the moon's anti-Jovian hemisphere shows numerous lineae, linear features created via a tectonic process in which crustal plates of water ice floating on a subsurface ocean (kept warm by tidal flexing) shift in relative position. Reddish regions are areas where the ice has a higher mineral content. The north polar region is at right. (Geologic features are annotated in Commons.)
- Image 13Six 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 14The asteroid 433 Eros was named after the Greek god of love Eros. This S-type asteroid is the second-largest near-Earth asteroid. This image shows the view looking from one end of the asteroid across the gouge on its underside and toward the opposite end.
- Image 15A 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 16Photo: Adam EvansThe Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years away. The image, created using a hydrogen-alpha filter, also shows Messier objects 32 and 110, as well as NGC 206 and the star Nu Andromedae. On December 15, 1612, German astronomer Simon Marius became the first person to describe the galaxy using a telescope.
- Image 17NGC 4414 is an unbarred spiral galaxy about 62 million light-years away in the constellation Coma Berenices. It is a flocculent spiral galaxy, with short segments of spiral structure but without the dramatic well-defined spiral arms of a grand design spiral. NGC 4414 is a very isolated galaxy, with no signs of past interactions with other galaxies.
- Image 18Photo 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 19Uranus is the seventh planet from the Sun and the fourth most massive in the Solar System. In this photograph from 1986 the planet appears almost featureless, but recent terrestrial observations have found seasonal changes to be occurring.
- Image 20A 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 21Map credit: Ignace-Gaston PardiesIgnace-Gaston Pardies (1636–1673) was a French Catholic priest and scientist. His celestial atlas, entitled Globi coelestis in tabulas planas redacti descriptio, comprised six charts of the night sky and was first published in 1674. The atlas uses a gnomonic projection so that the plates make up a cube of the celestial sphere. The constellation figures are drawn from Uranometria, but were carefully reworked and adapted to a broader view of the sky. This is the second plate from a 1693 edition of Pardies's atlas, featuring constellations including Pegasus and Andromeda, visible in the northern sky.
- Image 22Photograph: NASA/JPL-Caltech/University of ArizonaThe Helix Nebula is a large planetary nebula located in the constellation Aquarius. Discovered by Karl Ludwig Harding, probably before 1824, it is one of the closest to Earth of all the bright planetary nebulae, about 215 parsecs (700 light-years) away. It is similar in appearance to the Cat's Eye Nebula and the Ring Nebula.
Space-related portals
General images
- Image 1Artist's impression of dust formation around a supernova explosion. (from Cosmic dust)
- Image 2Reconstruction of solar activity over 11,400 years. Period of equally high activity over 8,000 years ago marked. (from Space climate)
- 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 4Spatial 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 6Concept art for a NASA Vision mission (from Space exploration)
- Image 7A computer-generated map of objects orbiting Earth, as of 2005. About 95% are debris, not working artificial satellites (from Outer space)
- Image 8Buzz Aldrin taking a core sample of the Moon during the Apollo 11 mission (from Space exploration)
- Image 10Smooth chondrite interplanetary dust particle. (from Cosmic dust)
- Image 11Astronaut Buzz Aldrin had a personal Communion service when he first arrived on the surface of the Moon. (from Space exploration)
- Image 12Space 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 13Major elements of 200 stratospheric interplanetary dust particles. (from Cosmic dust)
- Image 14Saudi officials inspect a crashed PAM-D module in January 2001. (from Space debris)
- Image 15Model of Vostok spacecraft (from Space exploration)
- Image 17Voyager 1 is the first artificial object to reach the interstellar medium. (from Interstellar medium)
- Image 18Atmospheric 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 19Growth 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 20Bow shock formed by the magnetosphere of the young star LL Orionis (center) as it collides with the Orion Nebula flow
- Image 22Perseverance's backshell sitting upright on the surface of Jezero Crater (from Space debris)
- Image 24The Long Duration Exposure Facility (LDEF) is an important source of information on small-particle space debris. (from Space debris)
- Image 25Cosmic dust of the Horsehead Nebula as revealed by the Hubble Space Telescope. (from Cosmic dust)
- Image 26The 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 27A proposed timeline of the origin of space, from physical cosmology (from Outline of space science)
- Image 28Spent upper stage of a Delta II rocket, photographed by the XSS 10 satellite (from Space debris)
- Image 30Spatial 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 33Apollo CSM in lunar orbit (from Space exploration)
- Image 34A micrometeoroid left this crater on the surface of Space Shuttle Challenger's front window on STS-7. (from Space debris)
- Image 35Artistic image of a rocket lifting from a Saturn moon (from Space exploration)
- Image 37The black background is outer space as seen from Earth's surface at night. The interplanetary dust cloud is illuminated and visible as zodiacal light, with its parts the false dawn, gegenschein and the rest of its band, which is visually crossed by the Milky Way (from Outer space)
- Image 38For 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, 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 39Objects in Earth orbit including fragmentation debris, November 2020, NASA: ODPO (from Space debris)
- Image 40Astronaut Piers Sellers during the third spacewalk of STS-121, a demonstration of orbiter heat shield repair techniques (from Outline of space science)
- Image 41A MESSENGER image from 18,000 km showing a region about 500 km across (2008) (from Space exploration)
- Image 42The diversity found in the different types and scales of astronomical objects make the field of study increasingly specialized. (from Outline of space science)
- Image 43Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while outside their spacecraft.
- Image 44The boundary between space and Earth, at an altitude of 100 km, roughly where the yellow line of airglow is visible. (from Outer space)
- Image 45Apollo 16 LEM Orion, the Lunar Roving Vehicle and astronaut John Young (1972) (from Space exploration)
- Image 47Near-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 48Known orbit planes of Fengyun-1C debris one month after the weather satellite's disintegration by the Chinese ASAT (from Space debris)
- Image 49Vanguard 1 is expected to remain in orbit for 240 years. (from Space debris)
- Image 50Map 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 51Gabbard 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 52A laser-guided observation of the Milky Way Galaxy at the Paranal Observatory in Chile in 2010 (from Outline of space science)
- Image 53Cosmic dust of the Andromeda Galaxy as revealed in infrared light by the Spitzer Space Telescope. (from Cosmic dust)
- Image 55Debris density in low Earth orbit (from Space debris)
- Image 56Astronomers 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 57Timeline of the expansion of the universe, where space, including hypothetical non-observable portions of the universe, is represented at each time by the circular sections. On the left, the dramatic expansion occurs in the inflationary epoch; and at the center, the expansion accelerates (artist's concept; neither time nor size are to scale). (from Outer space)
- Image 58Debris 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 59Infographic showing the space debris situation in different kinds of orbits around Earth (from Space debris)
- Image 60The original Magdeburg hemispheres (left) used to demonstrate Otto von Guericke's vacuum pump (right)
- Image 61Illustration of Earth's atmosphere gradual transition into outer space (from Outer space)
- Image 63Earth and the Moon as seen from cislunar space on the 2022 Artemis 1 mission (from Outer space)
- Image 64Conventional 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 66The 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 69A dusty trail from the early Solar System to carbonaceous dust today. (from Cosmic dust)
- Image 70Outer space from the International Space Station at 400 km (250 mi) altitude in low Earth orbit. In the background the Milky Way's interstellar space is visible, as well as in the foreground, above Earth, the airglow of the ionosphere just below and beyond the so-defined edge of space the Kármán line in the thermosphere (from Outer space)
- Image 73This light-year-long knot of interstellar gas and dust resembles a caterpillar. (from Interstellar medium)
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?
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