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A1689-zD1
A1689-zD1 is a galaxy in the Virgo constellation. It was a candidate for the most distant and therefore earliest-observed galaxy discovered , based on a photometric redshift. If the redshift, z~7.6, is correct, it would explain why the galaxy's faint light reaches us at infrared wavelengths. It could only be observed with Hubble Space Telescope's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Spitzer Space Telescope's Infrared Array Camera exploiting the natural phenomenon of gravitational lensing: the galaxy cluster Abell 1689, which lies between Earth and A1689-zD1, at a distance of 2.2 billion light-years from us, functions as a natural "magnifying glass" for the light from the far more distant galaxy which lies directly behind it, at 700 million years after the Big Bang, as seen from Earth. See also * IOK-1 * UDFy-38135539 * List of the most distant astronomical objects This article documents the most distant astronomical objects discovered and verifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of The Most Distant Astronomical Objects
This article documents the most distant astronomical objects discovered and verified so far, and the time periods in which they were so classified. For comparisons with the light travel distance of the astronomical objects listed below, the age of the universe since the Big Bang is currently estimated as 13.787±0.020 Gyr. Distances to remote objects, other than those in nearby galaxies, are nearly always inferred by measuring the cosmological redshift of their light. By their nature, very distant objects tend to be very faint, and these distance determinations are difficult and subject to errors. An important distinction is whether the distance is determined via spectroscopy or using a photometric redshift technique. The former is generally both more precise and also more reliable, in the sense that photometric redshifts are more prone to being wrong due to confusion with lower redshift sources that may have unusual spectra. For that reason, a spectroscopic redshift is conventio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and simultaneous increase in frequency and energy, is known as a negative redshift, or blueshift. The terms derive from the colours red and blue which form the extremes of the visible light spectrum. In astronomy and cosmology, the three main causes of electromagnetic redshift are # The radiation travels between objects which are moving apart (" relativistic" redshift, an example of the relativistic Doppler effect) #The radiation travels towards an object in a weaker gravitational potential, i.e. towards an object in less strongly curved (flatter) spacetime (gravitational redshift) #The radiation travels through expanding space (cosmological redshift). The observation that all sufficiently distant light sources show redshift corresponding to their distance from Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IOK-1
IOK-1 is a distant galaxy in the constellation Coma Berenices. When discovered in 2006, it was the oldest and most distant galaxy ever found, at redshift 6.96. It was discovered in April 2006 by Masanori Iye at National Astronomical Observatory of Japan using the Subaru Telescope in Hawaii and is seen as it was 12.88 billion years ago. Its emission of Lyman alpha radiation has a redshift of 6.96, corresponding to just 750 million years after the Big Bang. While some scientists have claimed other objects (such as Abell 1835 IR1916) to be even older, the IOK-1's age and composition have been more reliably established. "IOK" stands for the observers' names Iye, Ota, and Kashikawa. See also *Abell 2218 *Abell 370 *A1689-zD1 *UDFy-38135539 *List of the most distant astronomical objects This article documents the most distant astronomical objects discovered and verified so far, and the time periods in which they were so classified. For comparisons with the light travel distance of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abell 1689
Abell 1689 is a galaxy cluster in the constellation Virgo (constellation), Virgo over 2.3 billion light-years away. Details Abell 1689 is one of the biggest and most massive galaxy clusters known and acts as a gravitational lens, distorting the images of galaxies that lie behind it. It has the largest system of gravitational arcs ever found. Abell 1689 shows over 160,000 globular clusters, the largest population ever found. There is evidence of merging and gases in excess of 100 million degrees. The very large mass of this cluster makes it useful for the study of dark matter and gravitational lensing. At the time of its discovery in 2008, one of the lensed galaxies, A1689-zD1, was the most List of the most distant astronomical objects, distant galaxy found. Gallery File:Gravitationell-lins-4.jpg, Yellow galaxies belong to the cluster itself. Red and blue are background galaxies gravitational lens, gravitationally lensed. File:Abell 1689.jpg, Mass map of Abell 1689. File:Glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around 1 millimeter (300 GHz) to the nominal red edge of the visible spectrum, around 700 nanometers (430 THz). Longer IR wavelengths (30 μm-100 μm) are sometimes included as part of the terahertz radiation range. Almost all black-body radiation from objects near room temperature is at infrared wavelengths. As a form of electromagnetic radiation, IR propagates energy and momentum, exerts radiation pressure, and has properties corresponding to both those of a wave and of a particle, the photon. It was long known that fires emit invisible heat; in 1681 the pioneering experimenter Edme Mariotte showed that glass, though transparent to sunlight, obstructed radiant heat. In 1800 the astronomer Sir William Herschel discovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Galaxies
A dwarf galaxy is a small galaxy composed of about 1000 up to several billion stars, as compared to the Milky Way's 200–400 billion stars. The Large Magellanic Cloud, which closely orbits the Milky Way and contains over 30 billion stars, is sometimes classified as a dwarf galaxy; others consider it a full-fledged galaxy. Dwarf galaxies' formation and activity are thought to be heavily influenced by interactions with larger galaxies. Astronomers identify numerous types of dwarf galaxies, based on their shape and composition. Formation One theory states that most galaxies, including dwarf galaxies, form in association with dark matter, or from gas that contains metals. However, NASA's Galaxy Evolution Explorer space probe identified new dwarf galaxies forming out of gases with low metallicity. These galaxies were located in the Leo Ring, a cloud of hydrogen and helium around two massive galaxies in the constellation Leo. Because of their small size, dwarf galaxies have bee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxies
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies. Galaxies are categorized according to their visual morphology as elliptical, spiral, or irregular. Many are thought to have supermassive black holes at their centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UDFy-38135539
UDFy-38135539 (also known as "HUDF.YD3") is the Hubble Ultra Deep Field (UDF) identifier for a galaxy which was calculated to have a light travel time of 13.1 billion years with a present proper distance of around 30 billion light-years. It was discovered by three teams in September 2009 in sensitive infrared Hubble Space Telescope images and identified by these as source UDF-38135539 ( R Bouwens ''et al.''), source HUDF.YD3 (A Bunker ''et al.'') and source 1721 (R McLure ''et al.''), and additionally reported in the ''Astrophysical Journal'', and the ''Monthly Notices of the Royal Astronomical Society''. All teams independently identified the source to likely be an extremely distant galaxy because there was no measurable light at visible wavelengths (caused by absorption of hydrogen gas along the line of sight). Following the discovery of this candidate distant galaxy, another team targeted this object with ground-based spectroscopy to confirm the distance, reporting a reds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Bang
The Big Bang event is a physical theory that describes how the universe expanded from an initial state of high density and temperature. Various cosmological models of the Big Bang explain the evolution of the observable universe from the earliest known periods through its subsequent large-scale form. These models offer a comprehensive explanation for a broad range of observed phenomena, including the abundance of light elements, the cosmic microwave background (CMB) radiation, and large-scale structure. The overall uniformity of the Universe, known as the flatness problem, is explained through cosmic inflation: a sudden and very rapid expansion of space during the earliest moments. However, physics currently lacks a widely accepted theory of quantum gravity that can successfully model the earliest conditions of the Big Bang. Crucially, these models are compatible with the Hubble–Lemaître law—the observation that the farther away a galaxy is, the faster it is mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More solar e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy Cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-largest known gravitationally bound structures in the universe after galaxy filaments and were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. One of the key features of clusters is the intracluster medium (ICM). The ICM consists of heated gas between the galaxies and has a peak temperature between 2–15 keV that is dependent on the total mass of the cluster. Galaxy clusters should not be confused with ''galactic clusters'' (also known as open clusters), which are star clusters ''within'' galaxies, or with globular clusters, which typically orbit galaxies. Small aggregates of galaxies are referred to as galaxy groups rather than clusters of galaxies. The galaxy groups and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Lens
A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein's general theory of relativity. Treating light as corpuscles travelling at the speed of light, Newtonian physics also predicts the bending of light, but only half of that predicted by general relativity. Although Einstein made unpublished calculations on the subject in 1912, Orest Khvolson (1924) and Frantisek Link (1936) are generally credited with being the first to discuss the effect in print. However, this effect is more commonly associated with Einstein, who published an article on the subject in 1936. Fritz Zwicky posited in 1937 that the effect could allow galaxy clusters to act as gravitational lenses. It was not until 1979 that this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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