211 relations: Ablation, Accretion (astrophysics), Albert Einstein, Alpha particle, American Physical Society, Angular momentum, Anomalous X-ray pulsar, Antony Hewish, Asteroseismology, Atomic nucleus, Binary pulsar, Binary star, Binary system, Binding energy, Birefringence, Black hole, Calvera (X-ray source), Centaurus, Centaurus X-3, Chandra X-ray Observatory, Chandrasekhar limit, Chemical element, Chthonian planet, Circumbinary planet, Compact star, Constellation, Crab Nebula, Crab Pulsar, Degenerate matter, Derivative, Dimensionless quantity, Donald C. Backer, Down quark, Dragon's Egg, Earth, Electric charge, Electric field, Electromagnetic radiation, Electromagnetic spectrum, Electron, Electron capture, Electron–positron annihilation, Electroweak star, Equation of state, Escape velocity, Exoplanet, Exotic star, Franco Pacini, Frequency, Fritz Zwicky, ..., Gamma ray, Gamma-ray burst, General relativity, Giant star, Glitch (astronomy), Gravitational binding energy, Gravitational collapse, Gravitational lens, Gravitational wave, Gravity, Great Pyramid of Giza, GW170817, Helium, Hertz, Hertzsprung–Russell diagram, Hubble Space Telescope, Hulse–Taylor binary, Hydrogen, Infrared, Interstellar medium, Iosif Shklovsky, Iron, James Chadwick, Jocelyn Bell Burnell, Joseph Hooton Taylor Jr., Kaon, Kelvin, Kilonova, Lev Landau, Light, Light-year, LIGO, LIGO Scientific Collaboration, Litre, Luminosity, Magellanic Clouds, Magnetar, Magnetic field, Magnetic flux, Magnetic levitation, Magnetosphere, Main sequence, Marta Burgay, Mass, Mass–energy equivalence, Methods of detecting exoplanets, Milky Way, Millisecond pulsar, Moment of inertia, Moon, Multipole radiation, Nature (journal), Neutrino, Neutron, Neutron star merger, Neutron star spin-up, Neutron-star oscillation, Neutronium, Nobel Prize in Physics, Nuclear drip line, Nuclear pasta, Nucleon, Optical pulsar, Orders of magnitude (numbers), Osmium, Pair production, Parsec, Pauli exclusion principle, Periodic function, Photodisintegration, Photon, Photon sphere, Pion, Polarization (waves), Preon, Preon star, Proton, PSR B1257+12, PSR B1257+12 A, PSR B1509-58, PSR B1620-26, PSR B1919+21, PSR B1937+21, PSR J0108-1431, PSR J0348+0432, PSR J0737-3039, PSR J1614–2230, PSR J1748-2446ad, PSR J1903+0327, Pulsar, Pulsar planet, Pulse (physics), QCD matter, Quake (natural phenomenon), Quantum chromodynamics, Quark star, Radio wave, Radio-quiet neutron star, Red giant, Revolutions per minute, Riccardo Giacconi, Rotating radio transient, Rotation around a fixed axis, Rotation period, Russell Alan Hulse, RX J1856.5-3754, Samuel Okoye, Science (journal), Scientific American, Scorpius X-1, Shapiro time delay, Sky & Telescope, SN 1054, Soft gamma repeater, Solar mass, Spaghettification, Special relativity, Spectral density, Speed of light, Spheroid, Standard conditions for temperature and pressure, Standard gravity, Stellar black hole, Stellar collision, Stellar evolution, Stellar structure, Strange matter, Strange quark, Strange star, Strong interaction, Superconductivity, Superfluidity, Supernova, Supernova nucleosynthesis, Supernova remnant, Surface gravity, SWIFT J1756.9-2508, Synchrotron radiation, Tesla (unit), The Magnificent Seven, The Magnificent Seven (neutron stars), The New York Times, Tidal force, Time dilation, Tolman–Oppenheimer–Volkoff limit, Tonne, Type Ib and Ic supernovae, Type II supernova, Ultraviolet, Up quark, Vacuum permeability, Vacuum polarization, Virgo interferometer, Walter Baade, Weight, White dwarf, X-ray, X-ray binary, X-ray burster, X-ray pulsar, XTE J1739-285. Expand index (161 more) » « Shrink index
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes.
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, in an accretion disk.
Albert Einstein (14 March 1879 – 18 April 1955) was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).
Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus.
The American Physical Society (APS) is the world's second largest organization of physicists.
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum.
Anomalous X-ray Pulsars (AXPs) are now widely believed to be magnetars—young, isolated, highly magnetized neutron stars.
Antony Hewish (born 11 May 1924) is a British radio astronomer who won the Nobel Prize for Physics in 1974 (together with fellow radio-astronomer Martin Ryle) for his role in the discovery of pulsars.
Asteroseismology or astroseismology is the study of oscillations in stars.
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.
A binary pulsar is a pulsar with a binary companion, often a white dwarf or neutron star.
A binary star is a star system consisting of two stars orbiting around their common barycenter.
A binary system is a system of two astronomical bodies which are close enough that their gravitational attraction causes them to orbit each other around a barycenter (also see animated examples).
Binding energy (also called separation energy) is the minimum energy required to disassemble a system of particles into separate parts.
Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light.
A black hole is a region of spacetime exhibiting such strong gravitational effects that nothing—not even particles and electromagnetic radiation such as light—can escape from inside it.
In astronomy, Calvera is a nickname—based on the villain in the 1960 film The Magnificent Seven—of an X-ray source known as 1RXS J141256.0+792204 in the ROSAT All-Sky Survey Bright Source Catalog (RASS/BSC).
Centaurus is a bright constellation in the southern sky.
Centaurus X-3 (4U 1118-60) is an X-ray pulsar with a period of 4.84 seconds.
The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space observatory launched on STS-93 by NASA on July 23, 1999.
The Chandrasekhar limit is the maximum mass of a stable white dwarf star.
A chemical element is a species of atoms having the same number of protons in their atomic nuclei (that is, the same atomic number, or Z).
Chthonian planets (sometimes 'cthonian') are a hypothetical class of celestial objects resulting from the stripping away of a gas giant's hydrogen and helium atmosphere and outer layers, which is called hydrodynamic escape.
A circumbinary planet is a planet that orbits two stars instead of one.
In astronomy, the term "compact star" (or "compact object") refers collectively to white dwarfs, neutron stars, and black holes.
A constellation is a group of stars that are considered to form imaginary outlines or meaningful patterns on the celestial sphere, typically representing animals, mythological people or gods, mythological creatures, or manufactured devices.
The Crab Nebula (catalogue designations M1, NGC 1952, Taurus A) is a supernova remnant in the constellation of Taurus.
The Crab Pulsar (PSR B0531+21) is a relatively young neutron star.
Degenerate matter is a highly dense state of matter in which particles must occupy high states of kinetic energy in order to satisfy the Pauli exclusion principle.
The derivative of a function of a real variable measures the sensitivity to change of the function value (output value) with respect to a change in its argument (input value).
In dimensional analysis, a dimensionless quantity is a quantity to which no physical dimension is assigned.
Donald C. Backer (November 9, 1943 – July 25, 2010) was an American astrophysicist who primarily worked in radio astronomy.
The down quark or d quark (symbol: d) is the second-lightest of all quarks, a type of elementary particle, and a major constituent of matter.
Dragon's Egg is a 1980 hard science fiction novel by Robert L. Forward.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.
An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.
In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.
The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shell.
Electron–positron annihilation occurs when an electron and a positron (the electron's antiparticle) collide.
An electroweak star is a theoretical type of exotic star, whereby the gravitational collapse of the star is prevented by radiation pressure resulting from electroweak burning, that is, the energy released by conversion of quarks to leptons through the electroweak force.
In physics and thermodynamics, an equation of state is a thermodynamic equation relating state variables which describe the state of matter under a given set of physical conditions, such as pressure, volume, temperature (PVT), or internal energy.
In physics, escape velocity is the minimum speed needed for an object to escape from the gravitational influence of a massive body.
An exoplanet or extrasolar planet is a planet outside our solar system.
An exotic star is a hypothetical compact star composed of something other than electrons, protons, neutrons, or muons, and balanced against gravitational collapse by degeneracy pressure or other quantum properties.
Franco Pacini (May 10, 1939 – January 25, 2012) was an Italian astrophysicist and professor at the University of Florence.
Frequency is the number of occurrences of a repeating event per unit of time.
Fritz Zwicky (February 14, 1898 – February 8, 1974) was a Swiss astronomer.
A gamma ray or gamma radiation (symbol γ or \gamma), is penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei.
In gamma-ray astronomy, gamma-ray bursts (GRBs) are extremely energetic explosions that have been observed in distant galaxies.
General relativity (GR, also known as the general theory of relativity or GTR) is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics.
A giant star is a star with substantially larger radius and luminosity than a main-sequence (or dwarf) star of the same surface temperature.
A glitch is a sudden increase (up to 1 part in 106) in the rotational frequency of a rotation-powered pulsar, which usually decreases steadily due to braking provided by the emission of radiation and high-energy particles.
A gravitational binding energy is the minimum energy that must be added to a system for the system to cease being in a gravitationally bound state.
Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity.
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 towards the observer.
Gravitational waves are the disturbance in the fabric ("curvature") of spacetime generated by accelerated masses and propagate as waves outward from their source at the speed of light.
Gravity, or gravitation, is a natural phenomenon by which all things with mass or energy—including planets, stars, galaxies, and even light—are brought toward (or gravitate toward) one another.
The Great Pyramid of Giza (also known as the Pyramid of Khufu or the Pyramid of Cheops) is the oldest and largest of the three pyramids in the Giza pyramid complex bordering what is now El Giza, Egypt.
GW170817 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 17 August 2017.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second.
The Hertzsprung–Russell diagram, abbreviated H–R diagram, HR diagram or HRD, is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their stellar classifications or effective temperatures.
The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation.
PSR B1913+16 (also known as PSR J1915+1606, PSR 1913+16, and the Hulse–Taylor binary after its discoverers) is a pulsar (a radiating neutron star) which together with another neutron star is in orbit around a common center of mass, thus forming a binary star system.
Hydrogen is a chemical element with symbol H and atomic number 1.
Infrared radiation (IR) is electromagnetic radiation (EMR) with longer wavelengths than those of visible light, and is therefore generally invisible to the human eye (although IR at wavelengths up to 1050 nm from specially pulsed lasers can be seen by humans under certain conditions). It is sometimes called infrared light.
In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy.
Iosif Samuilovich Shklovsky (Ио́сиф Самуи́лович Шкло́вский; sometimes transliterated Josif, Josif, Shklovskii, Shklovskij) (July 1, 1916 – March 3, 1985) was a Soviet astronomer and astrophysicist.
Iron is a chemical element with symbol Fe (from ferrum) and atomic number 26.
Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932.
Dame Susan Jocelyn Bell Burnell (born 15 July 1943) is an astrophysicist from Northern Ireland who was credited with "one of the most significant scientific achievements of the 20th Century".
Joseph Hooton Taylor Jr. (born March 29, 1941) is an American astrophysicist and Nobel Prize in Physics laureate for his discovery with Russell Alan Hulse of a "new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation.".
In particle physics, a kaon, also called a K meson and denoted,The positively charged kaon used to be called τ+ and θ+, as it was supposed to be two different particles until the 1960s.
The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.
A kilonova (macronova or r-process supernova) is a transient astronomical event that occurs in a compact binary system when two neutron stars or a neutron star and a black hole merge into each other.
Lev Davidovich Landau (22 January 1908 - April 1968) was a Soviet physicist who made fundamental contributions to many areas of theoretical physics.
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a large-scale physics experiment and observatory to detect cosmic gravitational waves and to develop gravitational-wave observations as an astronomical tool.
The LIGO Scientific Collaboration (LSC) is a scientific collaboration of international physics institutes and research groups dedicated to the search for gravitational waves.
The litre (SI spelling) or liter (American spelling) (symbols L or l, sometimes abbreviated ltr) is an SI accepted metric system unit of volume equal to 1 cubic decimetre (dm3), 1,000 cubic centimetres (cm3) or 1/1,000 cubic metre. A cubic decimetre (or litre) occupies a volume of 10 cm×10 cm×10 cm (see figure) and is thus equal to one-thousandth of a cubic metre. The original French metric system used the litre as a base unit. The word litre is derived from an older French unit, the litron, whose name came from Greek — where it was a unit of weight, not volume — via Latin, and which equalled approximately 0.831 litres. The litre was also used in several subsequent versions of the metric system and is accepted for use with the SI,, p. 124. ("Days" and "hours" are examples of other non-SI units that SI accepts.) although not an SI unit — the SI unit of volume is the cubic metre (m3). The spelling used by the International Bureau of Weights and Measures is "litre", a spelling which is shared by almost all English-speaking countries. The spelling "liter" is predominantly used in American English. One litre of liquid water has a mass of almost exactly one kilogram, because the kilogram was originally defined in 1795 as the mass of one cubic decimetre of water at the temperature of melting ice. Subsequent redefinitions of the metre and kilogram mean that this relationship is no longer exact.
In astronomy, luminosity is the total amount of energy emitted per unit of time by a star, galaxy, or other astronomical object.
The Magellanic Clouds (or Nubeculae Magellani) are two irregular dwarf galaxies visible in the Southern Celestial Hemisphere; they are members of the Local Group and are orbiting the Milky Way galaxy.
A magnetar is a type of neutron star with an extremely powerful inferred magnetic field (\sim 10^ - 10^ G).
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
In physics, specifically electromagnetism, the magnetic flux (often denoted or) through a surface is the surface integral of the normal component of the magnetic field B passing through that surface.
Magnetic levitation, maglev, or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields.
A magnetosphere is the region of space surrounding an astronomical object in which charged particles are manipulated or affected by that object's magnetic field.
In astronomy, the main sequence is a continuous and distinctive band of stars that appear on plots of stellar color versus brightness.
Marta Burgay (30. November 1976, Torino) is an Italian radio astronomer whose initial claim to fame was being the discoverer of PSR J0737-3039, the first double pulsar (two pulsars orbiting each other), through using the 64-metre Parkes radio telescope in Australia.
Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.
In physics, mass–energy equivalence states that anything having mass has an equivalent amount of energy and vice versa, with these fundamental quantities directly relating to one another by Albert Einstein's famous formula: E.
Any planet is an extremely faint light source compared to its parent star.
The Milky Way is the galaxy that contains our Solar System.
A millisecond pulsar (MSP) is a pulsar with a rotational period in the range of about 1–10 milliseconds.
The moment of inertia, otherwise known as the angular mass or rotational inertia, of a rigid body is a tensor that determines the torque needed for a desired angular acceleration about a rotational axis; similar to how mass determines the force needed for a desired acceleration.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
Multipole radiation is a theoretical framework for the description of electromagnetic or gravitational radiation from time-dependent distributions of distant sources.
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
A neutrino (denoted by the Greek letter ν) is a fermion (an elementary particle with half-integer spin) that interacts only via the weak subatomic force and gravity.
A neutron star merger is a type of stellar collision.
Neutron star spin up is the name given to the increase in rotational speed over time first noted in Cen X-3 and Her X-1 but now observed in other X-ray pulsars.
Asteroseismology studies the internal structure of our Sun and other stars using oscillations.
Neutronium (sometimes shortened to neutrium, also referred to as neutrite) is a hypothetical substance composed purely of neutrons.
The Nobel Prize in Physics (Nobelpriset i fysik) is a yearly award given by the Royal Swedish Academy of Sciences for those who conferred the most outstanding contributions for mankind in the field of physics.
The nuclear drip line is the boundary delimiting the zone beyond which atomic nuclei decay by the emission of a proton or neutron.
In astrophysics and nuclear physics, nuclear pasta is a type of degenerate matter found within the crusts of neutron stars.
In chemistry and physics, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus.
An optical pulsar is a pulsar which can be detected in the visible spectrum.
This list contains selected positive numbers in increasing order, including counts of things, dimensionless quantity and probabilities.
Osmium (from Greek ὀσμή osme, "smell") is a chemical element with symbol Os and atomic number 76.
Pair production is the creation of an elementary particle and its antiparticle from a neutral boson.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously.
In mathematics, a periodic function is a function that repeats its values in regular intervals or periods.
Photodisintegration (also called phototransmutation) is a nuclear process in which an atomic nucleus absorbs a high-energy gamma ray, enters an excited state, and immediately decays by emitting a subatomic particle.
The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).
A photon sphere is a spherical region of space where gravity is strong enough that photons are forced to travel in orbits.
In particle physics, a pion (or a pi meson, denoted with the Greek letter pi) is any of three subatomic particles:,, and.
Polarization (also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations.
In particle physics, preons are point particles, conceived of as subcomponents of quarks and leptons.
A preon star is a theoretical type of compact star made of preons, which are "point-like" particles conceived to be subcomponents of quarks and leptons.
PSR B1257+12, previously designated PSR 1257+12, alternatively designated PSR J1300+1240, also named Lich, is a pulsar located 2,300 light years from the Sun in the constellation of Virgo.
PSR B1257+12 b, alternatively designated PSR B1257+12 A, also named Draugr, is an extrasolar planet approximately 2,300 light-years away in the constellation of Virgo.
PSR B1509-58 is a pulsar approximately 17,000 light-years away in the constellation of Circinus discovered by the Einstein X-Ray Observatory in 1982.
PSR B1620-26 is a binary star system located at a distance of 3,800 parsecs (12,400 light-years) in the globular cluster of Messier 4 (M4, NGC 6121) in the constellation of Scorpius.
PSR B1919+21 is a pulsar with a period of 1.3373 seconds and a pulse width of 0.04 seconds.
PSR B1937+21 is a pulsar located in the constellation Vulpecula a few degrees in the sky away from the first discovered pulsar, PSR B1919+21.
PSR J0108-1431 is a solitary pulsar located at a distance of about 130 parsecs (424 light years) in the constellation Cetus.
PSR J0348+0432 is a neutron star in a binary system with a white dwarf.
PSR J0737−3039 is the only known double pulsar.
PSR J1614–2230 is a neutron star in a binary system with a white dwarf.
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PSR J1903+0327 is a millisecond pulsar in a highly eccentric binary orbit.
A pulsar (from pulse and -ar as in quasar) is a highly magnetized rotating neutron star or white dwarf that emits a beam of electromagnetic radiation.
Pulsar planets are planets that are found orbiting pulsars, or rapidly rotating neutron stars.
In physics, a pulse is a generic term describing a single disturbance that moves through a transmission medium.
Quark matter or QCD matter refers to any of a number of theorized phases of matter whose degrees of freedom include quarks and gluons.
A quake is the result when the surface of a planet, moon or star begins to shake, usually as the consequence of a sudden release of energy transmitted as seismic waves, and potentially with great violence.
In theoretical physics, quantum chromodynamics (QCD) is the theory of the strong interaction between quarks and gluons, the fundamental particles that make up composite hadrons such as the proton, neutron and pion.
A quark star is a hypothetical type of compact exotic star, where extremely high temperature and pressure has forced nuclear particles to form a continuous state of matter that consists primarily of free quarks, which can be modeled using the Calabi–Yau manifold.
Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light.
A radio-quiet neutron star is a neutron star that does not seem to emit radio emissions.
A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses) in a late phase of stellar evolution.
Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min) is the number of turns in one minute.
Riccardo Giacconi (born October 6, 1931) is an Italian Nobel Prize-winning astrophysicist who laid the foundations of X-ray astronomy.
Rotating radio transients (RRATs) are sources of short, moderately bright, radio pulses, which were first discovered in 2006.
Rotation around a fixed axis or about a fixed axis of revolution or motion with respect to a fixed axis of rotation is a special case of rotational motion.
In astronomy, the rotation period of a celestial object is the time that it takes to complete one revolution around its axis of rotation relative to the background stars.
Russell Alan Hulse (born November 28, 1950) is an American physicist and winner of the Nobel Prize in Physics, shared with his thesis advisor Joseph Hooton Taylor Jr., "for the discovery of a new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation".
RX J1856.5-3754 (also called RX J185635-3754, RX J185635-375, and various other designations) is a nearby neutron star in the constellation Corona Australis.
Samuel Ejikeme Okoye (26 July 1939 – 18 November 2009) was a Nigerian astrophysicist from Amawbia in Anambra State, Nigeria.
Science, also widely referred to as Science Magazine, is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals.
Scientific American (informally abbreviated SciAm) is an American popular science magazine.
Scorpius X-1 is an X-ray source located roughly 9000 light years away in the constellation Scorpius.
The Shapiro time delay effect, or gravitational time delay effect, is one of the four classic solar-system tests of general relativity.
Sky & Telescope (S&T) is a monthly American magazine covering all aspects of amateur astronomy, including the following.
SN 1054 is a supernova that was first observed on 4 July 1054, and remained visible for around two years.
A soft gamma repeater (SGR) is an astronomical object which emits large bursts of gamma-rays and X-rays at irregular intervals.
The solar mass is a standard unit of mass in astronomy, equal to approximately.
In astrophysics, spaghettification (sometimes referred to as the noodle effect) is the vertical stretching and horizontal compression of objects into long thin shapes (rather like spaghetti) in a very strong non-homogeneous gravitational field; it is caused by extreme tidal forces.
In physics, special relativity (SR, also known as the special theory of relativity or STR) is the generally accepted and experimentally well-confirmed physical theory regarding the relationship between space and time.
The power spectrum S_(f) of a time series x(t) describes the distribution of power into frequency components composing that signal.
The speed of light in vacuum, commonly denoted, is a universal physical constant important in many areas of physics.
A spheroid, or ellipsoid of revolution, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters.
Standard conditions for temperature and pressure are standard sets of conditions for experimental measurements to be established to allow comparisons to be made between different sets of data.
The standard acceleration due to gravity (or standard acceleration of free fall), sometimes abbreviated as standard gravity, usually denoted by or, is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth.
A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a massive star.
A stellar collision is the coming together of two stars caused by gravity, gravitational radiation, or other mechanisms not well understood.
Stellar evolution is the process by which a star changes over the course of time.
Stars of different mass and age have varying internal structures.
Strange matter is a particular form of quark matter, usually thought of as a "liquid" of up, down and strange quarks.
The strange quark or s quark (from its symbol, s) is the third lightest of all quarks, a type of elementary particle.
A strange star is a quark star made of strange quark matter.
In particle physics, the strong interaction is the mechanism responsible for the strong nuclear force (also called the strong force or nuclear strong force), and is one of the four known fundamental interactions, with the others being electromagnetism, the weak interaction, and gravitation.
Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials, called superconductors, when cooled below a characteristic critical temperature.
Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without loss of kinetic energy.
A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.
Supernova nucleosynthesis is a theory of the nucleosynthesis of the natural abundances of the chemical elements in supernova explosions, advanced as the nucleosynthesis of elements from carbon to nickel in massive stars by Fred Hoyle in 1954.
A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova.
The surface gravity, g, of an astronomical or other object is the gravitational acceleration experienced at its surface.
SWIFT J1756.9-2508 is a millisecond pulsar with a rotation frequency of 182 Hz (period of 5.5 ms).
Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when charged particles are accelerated radially, i.e., when they are subject to an acceleration perpendicular to their velocity.
The tesla (symbol T) is a derived unit of magnetic flux density (informally, magnetic field strength) in the International System of Units.
The Magnificent Seven is a 1960 American Western film directed by John Sturges and starring Yul Brynner, Eli Wallach, Steve McQueen, Charles Bronson, Robert Vaughn, Brad Dexter, James Coburn and Horst Buchholz.
The Magnificent Seven is the informal name of a group of isolated young cooling neutron stars at a distance of 120 to 500 parsecs from Earth.
The New York Times (sometimes abbreviated as The NYT or The Times) is an American newspaper based in New York City with worldwide influence and readership.
The tidal force is an apparent force that stretches a body towards the center of mass of another body due to a gradient (difference in strength) in gravitational field from the other body; it is responsible for the diverse phenomena, including tides, tidal locking, breaking apart of celestial bodies and formation of ring systems within Roche limit, and in extreme cases, spaghettification of objects.
According to the theory of relativity, time dilation is a difference in the elapsed time measured by two observers, either due to a velocity difference relative to each other, or by being differently situated relative to a gravitational field.
The Tolman–Oppenheimer–Volkoff limit (or TOV limit) is an upper bound to the mass of cold, nonrotating neutron stars, analogous to the Chandrasekhar limit for white dwarf stars.
The tonne (Non-SI unit, symbol: t), commonly referred to as the metric ton in the United States, is a non-SI metric unit of mass equal to 1,000 kilograms;.
Type Ib and Type Ic supernovae are categories of supernovae that are caused by the core collapse of massive stars.
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star.
Ultraviolet (UV) is electromagnetic radiation with a wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays.
The up quark or u quark (symbol: u) is the lightest of all quarks, a type of elementary particle, and a major constituent of matter.
The physical constant μ0, (pronounced "mu naught" or "mu zero"), commonly called the vacuum permeability, permeability of free space, permeability of vacuum, or magnetic constant, is an ideal, (baseline) physical constant, which is the value of magnetic permeability in a classical vacuum.
In quantum field theory, and specifically quantum electrodynamics, vacuum polarization describes a process in which a background electromagnetic field produces virtual electron–positron pairs that change the distribution of charges and currents that generated the original electromagnetic field.
The Virgo interferometer is a large interferometer designed to detect gravitational waves predicted by the general theory of relativity.
Wilhelm Heinrich Walter Baade (March 24, 1893 – June 25, 1960) was a German astronomer who worked in the United States from 1931 to 1959.
In science and engineering, the weight of an object is related to the amount of force acting on the object, either due to gravity or to a reaction force that holds it in place.
A white dwarf, also called a degenerate dwarf, is a stellar core remnant composed mostly of electron-degenerate matter.
X-rays make up X-radiation, a form of electromagnetic radiation.
X-ray binaries are a class of binary stars that are luminous in X-rays.
X-ray bursters are one class of X-ray binary stars exhibiting periodic and rapid increases in luminosity (typically a factor of 10 or greater) that peak in the X-ray regime of the electromagnetic spectrum.
X-ray pulsars or accretion-powered pulsars are a class of astronomical objects that are X-ray sources displaying strict periodic variations in X-ray intensity.