Portal:Outer space

The Outer Space Portal

Introduction

Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while off-Earth and outside their spacecraft.

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

The Space Shuttle Challenger disaster was a space disaster that occurred at 11:39 a.m. EST on January 28, 1986, when the NASA Space Shuttle Challenger disintegrated 73 seconds into its flight after an O-ring seal in its right solid rocket booster (SRB) failed. The seal failure caused a flame leak from the solid rocket booster that impinged upon the adjacent external propellant tank. Within seconds, the flame caused structural failure of the external tank, and the orbiter broke up abruptly due to aerodynamic forces. The shuttle was destroyed and all seven crew members were killed. The disaster resulted in a 32-month hiatus in the shuttle program and the formation of the Rogers Commission, a special commission appointed by President Ronald Reagan to investigate the accident. The Rogers Commission found that NASA's organizational culture and decision-making processes had been a key contributing factor to the accident. The Challenger disaster has been used as a case study in many discussions of engineering safety and workplace ethics.

Selected picture

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  Geostationary orbit

  Animation credit: Cmglee

  This is an animation showing geocentric satellite orbits, to scale with the Earth, at 3,600 times actual speed. The second-outermost (shown in grey) is a geostationary orbit, 35,786 kilometres (22,236 miles) above Earth's equator and following the direction of Earth's rotation, with an orbital period matching the planet's rotation period (a geosynchronous orbit). An object in such an orbit will appear to occupy a fixed position in the sky. Some 300 kilometres (190 miles) farther away is the graveyard orbit (brown), used for satellites at the end of their operational lives. Nearer to the Earth are the orbits of navigational satellites, such as Galileo (turquoise), BeiDou (beige), GPS (blue) and GLONASS (red), in medium Earth orbits. Much closer to the planet, and within the inner Van Allen belt, are satellites in low Earth orbit, such as the Iridium satellite constellation (purple), the Hubble Space Telescope (green) and the International Space Station (magenta).
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  Tvashtar Paterae

  Photo credit: New Horizons probe

  An 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.
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  Ignace-Gaston Pardies

  Map credit: Ignace-Gaston Pardies

  Ignace-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.
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  Mercury (planet)

  Photograph: NASA/APL/CIS; edit: Jjron

  Mercury is the smallest and closest to the Sun of the eight planets in the Solar System. It has no known natural satellites. The planet is named after the Roman deity Mercury, the messenger to the gods.
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  Eagle Nebula

  Photo credit: NASA

  The 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.
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  TRACE image of sunspots

  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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  Pillars of Creation

  Photograph: NASA, ESA, and the Hubble Heritage Team

  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.
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  Sombrero Galaxy

  Sombrero Galaxy M104

  Credit: NASA / STScI

  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.

  
  
  
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  STS-116

  Photo credit: NASA

  NASA 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.
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  Planet Mars

  Mars (planet)

  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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  Jupiter

  Diagram: Kelvin Song

  A 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.
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  Space Shuttle Endeavour

  Photo: NASA/Crew of Expedition 22

  Space 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.
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  Mars

  Photograph credit: European Space Agency

  Mars 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.
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  Space Shuttle Atlantis launch plume

  Space Shuttle program

  Credit: NASA/Fir0002

  The 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.

  
  
  
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  James Webb Space Telescope

  Photo: NASA/MSFC/David Higginbotham/Emmett Given

  Six 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.
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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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  NGC 6357

  Photograph credit: NASA

  NGC 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.
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  Pioneer plaque

  Pioneer plaque

  Credit: Carl Sagan, Frank Drake, Linda Salzman Sagan

  The 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.
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  The Day the Earth Smiled

  Photograph: NASA/JPL-Caltech/SSI

  The 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.
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  Lunar phase

  Image: Tom Ruen

  An 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.
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  Astronaut Bruce McCandless using a Manned Maneuvering Unit

  Manned Maneuvering Unit

  Credit: NASA

  A 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.

  
  
  
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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 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.

  
  
  

Space-related portals

General images

The following are images from various outer space-related articles on Wikipedia.

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  Asteroid 4 Vesta, imaged by the Dawn spacecraft (2011) (from Space exploration)
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  Astronaut Piers Sellers during the third spacewalk of STS-121, a demonstration of orbiter heat shield repair techniques (from Outline of space science)
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  Illustration of a satellite breaking up into multiple pieces at higher altitudes (from Space debris)
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  Buzz Aldrin taking a core sample of the Moon during the 1969 Apollo 11 mission (from Space exploration)
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  View of an orbital debris hole made in the panel of the Solar Max satellite (from Space debris)
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  View from International Space Station, showing the yellow-green airglow of Earth's ionosphere with the Milky Way in the background. (from Outer space)
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  Apollo 16 LEM Orion, the Lunar Roving Vehicle and astronaut John Young (1972) (from Space exploration)
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  The diversity found in the different types and scales of astronomical objects make the field of study increasingly specialized. (from Outline of space science)
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  This light-year-long knot of interstellar gas and dust resembles a caterpillar. (from Interstellar medium)
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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)
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  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)
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  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)
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  Objects in Earth orbit including fragmentation debris, November 2020, NASA: ODPO (from Space debris)
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  Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while outside their spacecraft.
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  Illustration of Earth's atmosphere gradual transition into outer space (from Outer space)
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  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)
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  Bow shock formed by the magnetosphere of the young star LL Orionis (center) as it collides with the Orion Nebula flow
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  Growth of tracked objects in orbit and related events; efforts to manage outer space global commons have so far not reduced the total amount of debris or the growth of objects in orbit. (from Space debris)
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  Spent upper stage of a Delta II rocket, photographed by the XSS 10 satellite (from Space debris)
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  Major elements of 200 stratospheric interplanetary dust particles. (from Cosmic dust)
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  Structure of galactic space of the Milky Way, as viewed from the Solar System, with dark nebulas (white text) and star clouds (black text) labeled (from Outer space)
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  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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  A V-2 Rocket in the Peenemünde Museum in Germany (from Space exploration)
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  A micrometeoroid left this crater on the surface of Space Shuttle Challenger's front window on STS-7. (from Space debris)
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  Herbig–Haro object HH 110 ejects gas through interstellar space. (from Interstellar medium)
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  Concept art for a NASA Vision mission (from Space exploration)
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  Porous chondrite dust particle (from Cosmic dust)
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  Delta-v's in km/s for various orbital maneuvers (from Space exploration)
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  Artistic image of a rocket lifting from a Saturn moon (from Space exploration)
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  A dusty trail from the early Solar System to carbonaceous dust today. (from Cosmic dust)
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  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)
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  Tupan Patera on Jupiter's moon Io (from Space exploration)
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  Apollo Command Service Module in lunar orbit (from Space exploration)
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  Astronaut Buzz Aldrin had a personal Communion service when he first arrived on the surface of the Moon. (from Space exploration)
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  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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  After reentry, Delta 2 second stage pieces were found in South Africa. (from Space debris)
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  Baker–Nunn cameras were widely used to study space debris. (from Space debris)
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  Astronomers used the James Webb Space Telescope to image the warm dust around a nearby young star, Fomalhaut, to study the first asteroid belt ever seen outside the Solar System in infrared light. (from Cosmic dust)
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  Perseverance's backshell sitting upright on the surface of Jezero Crater (from Space debris)
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  Collision on Launch Avoidance lead to delayed spacecraft launches to avoid potential conjunctions/collisions during launch. Seen here is a Collision Avoidance analysis that mandated a four-minute delay for the launch of SPADEX in 2024. (from Space debris)
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  The famous Earthrise photo, the first of its kind taken by a human (from Outer space)
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  A proposed timeline of the origin of space, from physical cosmology (from Outline of space science)
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  Artist's impression of dust formation around a supernova explosion. (from Cosmic dust)
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  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)
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  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)
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  A computer-generated map of objects orbiting Earth, as of 2005. About 95% are debris, not working artificial satellites (from Outer space)
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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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  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)
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  Three-dimensional structure in Pillars of Creation. (from Interstellar medium)
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  Known orbit planes of Fengyun-1C debris one month after the weather satellite's disintegration by the Chinese ASAT (from Space debris)

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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