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Final Parsec Problem
A binary black hole (BBH) is a system consisting of two black holes in close orbit around each other. Like black holes themselves, binary black holes are often divided into stellar binary black holes, formed either as remnants of high-mass binary star systems or by dynamic processes and mutual capture; and binary supermassive black holes, believed to be a result of galactic mergers. For many years, proving the existence of binary black holes was made difficult because of the nature of black holes themselves and the limited means of detection available. However, in the event that a pair of black holes were to merge, an immense amount of energy should be given off as gravitational waves, with distinctive waveforms that can be calculated using general relativity. Therefore, during the late 20th and early 21st century, binary black holes became of great interest scientifically as a potential source of such waves and a means by which gravitational waves could be proven to exist. Bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBH Gravitational Lensing Of Gw150914
BBH may refer to: * Brown Brothers Harriman & Co., a private investment bank in the United States * Bartle Bogle Hegarty, British advertising agency * Bruce Barrymore Halpenny, writer and historian * The Darkstalkers character Bbhood#Baby Bonnie Hood, Baby Bonnie Hood * Baltic Beverages Holding, now owned by the Carlsberg Group * Bún bò Huế, a noodle dish from Vietnam * Baseball Heaven, an artificial turf baseball complex on Long Island * Binary black hole, an astrophysical binary star system of two black holes orbiting each other * Byun Baek-hyun, a South Korean singer and actor * Brest Bretagne Handball, a French handball club See also * BBHS (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CBS News
CBS News is the news division of the American television and radio service CBS. CBS News television programs include the ''CBS Evening News'', ''CBS Mornings'', news magazine programs '' CBS News Sunday Morning'', '' 60 Minutes'', and '' 48 Hours'', and Sunday morning political affairs program ''Face the Nation''. CBS News Radio produces hourly newscasts for hundreds of radio stations, and also oversees CBS News podcasts like '' The Takeout Podcast''. CBS News also operates a 24-hour digital news network. Up until April 2021, the president and senior executive producer of CBS News was Susan Zirinsky, who assumed the role on March 1, 2019. Zirinsky, the first female president of the network's news division, was announced as the choice to replace David Rhodes on January 6, 2019. The announcement came amid news that Rhodes would step down as president of CBS News "amid falling ratings and the fallout from revelations from an investigation into sexual misconduct allegations" ag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Slingshot
In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typically to save propellant and reduce expense. Gravity assistance can be used to accelerate a spacecraft, that is, to increase or decrease its speed or redirect its path. The "assist" is provided by the motion of the gravitating body as it pulls on the spacecraft. Any gain or loss of kinetic energy and velocity by a passing spacecraft is correspondingly lost or gained by the gravitational body, in accordance with Newton's Third Law. The gravity assist maneuver was first used in 1959 when the Soviet probe Luna 3 photographed the far side of Earth's Moon and it was used by interplanetary probes from Mariner 10 onward, including the two Voyager probes' notable flybys of Jupiter and Saturn. Explanation A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamical Friction
In astrophysics, dynamical friction or Chandrasekhar friction, sometimes called ''gravitational drag'', is loss of momentum and kinetic energy of moving bodies through gravitational interactions with surrounding matter in space. It was first discussed in detail by Subrahmanyan Chandrasekhar in 1943. Intuitive account An intuition for the effect can be obtained by thinking of a massive object moving through a cloud of smaller lighter bodies. The effect of gravity causes the light bodies to accelerate and gain momentum and kinetic energy (see slingshot effect). By conservation of energy and momentum, we may conclude that the heavier body will be slowed by an amount to compensate. Since there is a loss of momentum and kinetic energy for the body under consideration, the effect is called ''dynamical friction''. Another equivalent way of thinking about this process is that as a large object moves through a cloud of smaller objects, the gravitational effect of the larger object pulls ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperbolic Trajectory
In astrodynamics or celestial mechanics, a hyperbolic trajectory or hyperbolic orbit is the trajectory of any object around a central body with more than enough speed to escape the central object's gravitational pull. The name derives from the fact that according to Newtonian theory such an orbit has the shape of a hyperbola. In more technical terms this can be expressed by the condition that the orbital eccentricity is greater than one. Under simplistic assumptions a body traveling along this trajectory will coast towards infinity, settling to a final excess velocity relative to the central body. Similarly to parabolic trajectories, all hyperbolic trajectories are also escape trajectories. The specific energy of a hyperbolic trajectory orbit is positive. Planetary flybys, used for gravitational slingshots, can be described within the planet's sphere of influence using hyperbolic trajectories. Parameters describing a hyperbolic trajectory Like an elliptical orbit, a hyperbol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Wave Observation
Gravitational-wave astronomy is an emerging branch of observational astronomy which aims to use gravitational waves (minute distortions of spacetime predicted by Albert Einstein's theory of general relativity) to collect observational data about objects such as neutron stars and black holes, events such as supernovae, and processes including those of the early universe shortly after the Big Bang. Gravitational waves have a solid theoretical basis, founded upon the theory of relativity. They were first predicted by Einstein in 1916; although a specific consequence of general relativity, they are a common feature of all theories of gravity that obey special relativity. However, after 1916 there was a long debate whether the waves were actually physical, or artefacts of coordinate freedom in general relativity; this was not fully resolved until the 1950s. Indirect observational evidence for their existence first came in the late 1980s, from the monitoring of the PSR B1913+16, Hulse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PKS 1302-102
PKS 1302-102 is a quasar in the Virgo constellation, located at a distance of approximately 1.1 Gpc (around 3.5 billion light-years). It has an apparent magnitude of about 14.9 mag in the V band with a redshift of 0.2784. The quasar is hosted by a bright elliptical galaxy, with two neighboring companions at distances of 3 kpc and 6 kpc. The light curve of PKS 1302-102 appears to be sinusoidal with an amplitude of 0.14 mag and a period of 1,884 ± 88 days, which suggests evidence of a supermassive black hole binary. Possible black hole binary PKS 1302-102 was selected from the Catalina Real-Time Transient Survey as one of 20 quasars with apparent periodic variations in the light curve. Of these quasars, PKS 1302-102 appeared to be the best candidate in terms of sinusoidal behavior and other selection criteria, such as data coverage of more than 1.5 cycles in the measured period. One plausible interpretation of the apparent periodic behavior is the possibility of two superma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peculiar Velocity
Peculiar motion or peculiar velocity refers to the velocity of an object relative to a ''rest frame'' — usually a frame in which the average velocity of some objects is zero. Galactic astronomy In galactic astronomy, peculiar motion refers to the motion of an object (usually a star) relative to a Galactic rest frame. Local objects are commonly examined as to their vectors of position angle and radial velocity. These can be combined through vector addition to state the object's motion relative to the Sun. Velocities for local objects are sometimes reported with respect to the local standard of rest (LSR) – the average local motion of material in the galaxy – instead of the Sun's rest frame. Translating between the LSR and heliocentric rest frames requires the calculation of the Sun's peculiar velocity in the LSR. Cosmology In physical cosmology, peculiar velocity refers to the components of a galaxy's velocity that deviate from the Hubble flow. According to Hu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OJ287
OJ 287 is a BL Lac object 3.5 billion light-years from Earth that has produced quasi-periodic optical outbursts going back approximately 120 years, as first apparent on photographic plates from 1891. Seen on photographic plates since at least 1887, it was first detected at radio wavelengths during the course of the Ohio Sky Survey. It is a supermassive black hole binary. The intrinsic brightness of the flashes corresponds to over a trillion times the Sun's luminosity, greater than the entire Milky Way galaxy's light output. Characteristics Its central supermassive black hole is among the largest known, with a mass of 18.35 billion solar masses, more than six times the value calculated for the previous largest object . With such high mass, OJ 287 may fall into a proposed new classification of ultramassive black holes. Its Schwarzschild radius is ~362 AU, about 12 and 0.75 times the semimajor axes of the orbits of Neptune and dwarf planet Sedna, respectively. The optical li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EGSD2 J142033
EGSD may refer to: * East Greenwich School Department, a public school district located in East Greenwich, Rhode Island * EGSD, the ICAO code for Great Yarmouth – North Denes Airport, Great Yarmouth, England {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SDSS J104807 , a school in Delta, British Columbia, Canada
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SDSS may refer to: * Sloan Digital Sky Survey, a major multi-filter imaging and spectroscopic redshift survey * Social Democratic Party of Slovakia * Spatial Decision Support System, a GIS based decision aiding system * Independent Democratic Serb Party, a political party of Croatian Serbs (''Samostalna demokratska srpska stranka'' in Serbo-Croatian) * South Delta Secondary School South Delta Secondary (SDSS) is a public high school in Tsawwassen, British Columbia, Canada. There are approximately 1,500 students enrolled in each grade 8 through 12 (as of 2019/2020). Graduation rates in the years 2005 to 2010 vary between 9 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 6240
NGC 6240, also known as the Starfish Galaxy, is a nearby ultraluminous infrared galaxy (ULIRG) in the constellation Ophiuchus. The galaxy is the remnant of a merger between three smaller galaxies. The collision between the three progenitor galaxies has resulted in a single, larger galaxy with three distinct nuclei and a highly disturbed structure, including faint extensions and loops. Double nuclei Star formation versus supermassive black holes The power sources of ULIRGs in general has been greatly debated. Infrared light from galaxies generally originates from dust in the interstellar medium. ULIRGs are abnormally bright in the infrared. The infrared dust emission in ULIRGs is over one trillion times more luminous than the Sun (i.e. it has an infrared luminosity of ). Astronomers have speculated that either intense star formation regions or active galactic nuclei (which contain supermassive black holes) may be responsible for the intense dust heating that produces this em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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