The Outer Space Portal
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
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is two and a half times as massive as all of the other planets in our Solar System combined. Jupiter, along with Saturn, Uranus, and Neptune, is classified as a gas giant. When viewed from Earth, Jupiter can reach an apparent magnitude of -2.8, making it the fourth brightest object in the night sky. The planet was known by astronomers of ancient times and was associated with the mythology and religious beliefs of many cultures. Jupiter is primarily composed of hydrogen with only a small proportion of helium; it may also have a rocky core of heavier elements. The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. A prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the seventeenth century. Surrounding the planet is a faint planetary ring system and a powerful magnetosphere. There are also at least 67 moons, including the four large moons called the Galilean moons that were first discovered by Galileo Galilei in 1610. Jupiter has been explored on several occasions by robotic spacecraft, most notably during the early Pioneer and Voyager fly-by missions and later by the Galileo orbiter.
Selected picture
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The 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. -
Color-composite image of the Pleiades from the Digitized Sky Survey Credit: 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. -
Sombrero Galaxy The Sombrero Galaxy is a spiral galaxy in the Virgo constellation. It was discovered in the late 1700s. It is about 28 million light years away and is just faint enough to be invisible to the naked eye but easily visible with small telescopes. In our sky, it is about one-fifth the diameter of the full moon. M104 is moving away from Earth at about 1,000 kilometers per second. -
Image credit: NASAA 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). -
An animated view of Voyager I's approach to Jupiter. One frame of this image was taken each Jupiter day (approximately 10 hours) between January 6 and February 9, 1979, as the space probe flew from 58 million to 31 million kilometers from Jupiter during that time. The small, round, dark spots appearing in some frames are the shadows cast by the moons passing between Jupiter and the Sun, while the small, white flashes around the planet, are the moons themselves. -
Photo credit: Spirit roverA 360° panorama taken during the descent from the summit of Husband Hill, one of the Columbia Hills in Gusev crater, Mars. This stitched image is composed of 405 individual images taken with five different filters on the panoramic camera over the course of five Martian days. -
Photograph 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. -
NGC 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. -
Kepler's Supernova Credit: 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 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 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. -
Photo 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. -
Astronaut Steve Robinson on a spacewalk, August 2005 Credit: 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 credit: Dave JarvisAn illustration of relative astronomical orders of magnitude, starting with the terrestrial planets of the Solar System in image 1 (top left) and ending with the largest known star, VY Canis Majoris, at the bottom right. The biggest celestial body in each image is shown on the left of the next frame. -
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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Astronaut Bruce McCandless using a Manned Maneuvering Unit Credit: NASAA 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. -
Neptune 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. -
A 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. -
The 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. -
Photograph: NASA, ESA, A. Aloisi (STScI/ESA), and The Hubble Heritage (STScI/AURA)-ESA/Hubble CollaborationAn image of NGC 4449, highlighting its qualities as a starburst galaxy. NGC 4449, an irregular galaxy in the constellation Canes Venatici located about 12 million light years from Earth, has a rate of star formation twice that of the Milky Way's satellite galaxy, the Large Magellanic Cloud. Interactions with nearby galaxies are thought to have influenced this star formation. -
Image: Tom RuenAn animation of the phases of the Moon. As the Moon revolves around the Earth, the Sun lights the Moon from a different side, creating the different phases. In the image, the Moon appears to get bigger as well as "wobble" slightly. Tidal locking synchronizes the Moon's rotation period on its axis to match its orbital period around the earth. These two periods nearly cancel each other out, except that the Moon's orbit is elliptical. This causes its orbital motion to speed up when closer to the Earth, and slow down when farther away, causing the Moon's apparent diameter to change, as well as the wobbling motion observed. -
Photo: Yuri Beletsky, ESOA laser shoots towards the centre of the Milky Way from the Very Large Telescope facility in Chile, to provide a laser guide star, a reference point in the sky for the telescope's adaptive optics (AO) system. AO technology improves the performance of optical systems by reducing the effect of atmospheric distortion. AO was first envisioned by Horace W. Babcock in 1953, but did not come into common usage until advances in computer technology during the 1990s made the technique practical.
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Space-related portals
General images
The following are images from various outer space-related articles on Wikipedia.
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Infographic showing the space debris situation in different kinds of orbits around Earth (from Space debris) -
A computer-generated map of objects orbiting Earth, as of 2005. About 95% are debris, not working artificial satellites (from Outer space) -
Comet 103P/Hartley (2010) (from Space exploration) -
A proposed timeline of the origin of space, from physical cosmology (from Outline of space science) -
Distribution of Matter in a cubic section of the universe. The blue fiber-like structures represent matter, while the empty regions show the cosmic voids (from Outer space) -
Zodiacal light caused by cosmic dust. (from Cosmic dust) -
A micrometeoroid left this crater on the surface of Space Shuttle Challenger's front window on STS-7. (from Space debris) -
Debris 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) -
View of an orbital debris hole made in the panel of the Solar Max satellite (from Space debris) -
Apollo Command Service Module in lunar orbit (from Space exploration) -
The original Magdeburg hemispheres (left) used to demonstrate Otto von Guericke's vacuum pump (right) -
Astronaut Buzz Aldrin had a personal Communion service when he first arrived on the surface of the Moon. (from Space exploration) -
Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while outside their spacecraft. -
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Artistic image of a rocket lifting from a Saturn moon (from Space exploration) -
Cosmic dust of the Andromeda Galaxy as revealed in infrared light by the Spitzer Space Telescope. (from Cosmic dust) -
Smooth chondrite interplanetary dust particle. (from Cosmic dust) -
Delta-v's in km/s for various orbital maneuvers (from Space exploration) -
Conventional anti-satellite weapons such as the SM-3 missile remain legal under the law of armed conflict, even though they create hazardous space debris (from Outer space) -
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. -
Tupan Patera on Jupiter's moon Io (from Space exploration) -
Concept art for a NASA Vision mission (from Space exploration) -
Debris density in low Earth orbit (from Space debris) -
Objects in Earth orbit including fragmentation debris, November 2020, NASA: ODPO (from Space debris) -
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Vanguard 1 is expected to remain in orbit for 240 years. (from Space debris) -
Space 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) -
Spatial density of space debris by altitude according to ESA MASTER-2001, without debris from the Chinese ASAT and 2009 collision events (from Space debris) -
Perseverance's backshell sitting upright on the surface of Jezero Crater (from Space debris) -
Illustration of Earth's atmosphere gradual transition into outer space (from Outer space) -
A MESSENGER image from 18,000 km showing a region about 500 km across (2008) (from Space exploration) -
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The Long Duration Exposure Facility (LDEF) is an important source of information on small-particle space debris. (from Space debris) -
Reconstruction of solar activity over 11,400 years. Period of equally high activity over 8,000 years ago marked. (from Space climate) -
A 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) -
Near-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) -
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Gabbard 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) -
Atmospheric 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) -
A 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) -
After reentry, Delta 2 second stage pieces were found in South Africa. (from Space debris) -
Bow shock formed by the magnetosphere of the young star LL Orionis (center) as it collides with the Orion Nebula flow -
Apollo 16 LEM Orion, the Lunar Roving Vehicle and astronaut John Young (1972) (from Space exploration) -
Astronomers 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) -
Crew quarters on Zvezda, the base ISS crew module (from Space exploration) -
Baker-Nunn cameras were widely used to study space debris. (from Space debris) -
Voyager 1 is the first artificial object to reach the interstellar medium. (from Interstellar medium) -
South is up in the first image of Earth taken by a person, probably by Bill Anders (during the 1968 Apollo 8 mission) (from Outer space) -
Astronaut Piers Sellers during the third spacewalk of STS-121, a demonstration of orbiter heat shield repair techniques (from Outline of space science) -
First television image of Earth from space, taken by TIROS-1 (1960) (from Space exploration) -
Concept for a space-based solar power system to beam energy down to Earth (from Outer space) -
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Saudi officials inspect a crashed PAM-D module in January 2001. (from Space debris) -
Three-dimensional structure in Pillars of Creation. (from Interstellar medium) -
V-2 Rocket in the Peenemünde Museum (from Space exploration) -
The diversity found in the different types and scales of astronomical objects make the field of study increasingly specialized. (from Outline of space science) -
A dusty trail from the early Solar System to carbonaceous dust today. (from Cosmic dust) -
Illustration of a satellite breaking up into multiple pieces at higher altitudes (from Space debris) -
Map 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) -
Spatial 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) -
NASA computer-generated image of debris objects in Earth orbit, c. 2005 (from Space debris)
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Model of Vostok spacecraft (from Space exploration) -
View from International Space Station, showing the yellow-green airglow of Earth's ionosphere with the Milky Way in the background. (from Outer space) -
The 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). (from Interstellar medium) -
Space debris identified as WT1190F, burning up in a fireball over Sri Lanka (from Space debris) -
Major elements of 200 stratospheric interplanetary dust particles. (from Cosmic dust) -
Earth and the Moon as seen from cislunar space on the 2022 Artemis 1 mission (from Outer space) -
Growth 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) -
Known orbit planes of Fengyun-1C debris one month after the weather satellite's disintegration by the Chinese ASAT (from Space debris) -
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This light-year-long knot of interstellar gas and dust resembles a caterpillar. (from Interstellar medium) -
Porous chondrite dust particle (from Cosmic dust) -
Artist's impression of dust formation around a supernova explosion. (from Cosmic dust) -
For 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) -
Interstellar medium and astrosphere meeting (from Interstellar medium) -
A laser-guided observation of the Milky Way Galaxy at the Paranal Observatory in Chile in 2010 (from Outline of space science)
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Timeline of the expansion of the universe, where space is represented schematically at each time by circular sections. On the left, the dramatic expansion of inflation; at the center, the expansion accelerates (artist's concept; neither time nor size are to scale) (from Outer space)
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Newton's cannonball, an illustration of how objects can "fall" in a curve around the planet (from Outer space) -
Surface of Mars by the Spirit rover (2004) (from Space exploration)
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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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