Astrophysics

Cosmochemistry (from Greek κόσμος kósmos, "universe" and χημεία khemeía) or chemical cosmology is the study of the chemical composition of matter in the universe and the processes that led to those compositions.

Advanced Composition Explorer (ACE) is a NASA Explorers program Solar and space exploration mission to study matter comprising energetic particles from the solar wind, the interplanetary medium, and other sources.

A magnetosphere is the region of space surrounding an astronomical object in which charged particles are controlled by that object's magnetic field.

Plasma (from Greek πλάσμα, "anything formed") is one of the four fundamental states of matter, the others being solid, liquid, and gas.

Tired light is a class of hypothetical redshift mechanisms that was proposed as an alternative explanation for the redshift-distance relationship.

Przybylski's Star /ʃᵻˈbɪlskiz stɑːr/, or HD 101065, is a rapidly oscillating Ap star that is located at a distance of roughly 370 light-years (110 parsecs) from the Sun in the southern constellation of Centaurus.

Wolf–Rayet stars, often abbreviated as WR stars, are a heterogeneous set of stars with unusual spectra showing prominent broad emission lines of highly ionised helium and nitrogen or carbon.

The Kavli Prize was established in 2005 through a joint venture between the Norwegian Academy of Science and Letters, the Norwegian Ministry of Education and Research, and The Kavli Foundation.

The cosmic microwave background (CMB) is the thermal radiation left over from the time of recombination in Big Bang cosmology.

A black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence.

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.

Stellar rotation is the angular motion of a star about its axis.

Mira variables /ˈmaɪrə/ ("Mira", Latin, adj. - feminine form of adjective "wonderful"), named for the prototype star Mira, are a class of pulsating variable stars characterized by very red colours, pulsation periods longer than 100 days, and amplitudes greater than one magnitude in infrared and 2.

Kvant-1 (Russian: Квант-1; English: Quantum-I/1) (37KE) was the first module to be attached in 1987 to the Mir Core Module, which formed the core of the Soviet space station Mir.

Photodissociation, photolysis, or photodecomposition is a chemical reaction in which a chemical compound is broken down by photons.

In astronomy, stellar classification is the classification of stars based on their spectral characteristics.

The Hubble sequence is a morphological classification scheme for galaxies invented by Edwin Hubble in 1926.

An accretion disk is a structure (often a circumstellar disk) formed by diffused material in orbital motion around a massive central body.

The neon-burning process is a set of nuclear fusion reactions that take place in massive stars (at least 8 Solar masses).

A Moreton wave is the chromospheric signature of a large-scale solar coronal shock wave.

Gamma-ray bursts (GRBs) are extremely energetic explosions that have been observed in distant galaxies.

In astronomy, the interstellar medium (ISM) is the matter that exists in the space between the star systems in a galaxy.

The Fermi Gamma-ray Space Telescope (FGST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit.

In physics, redshift happens when light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum.

Neutronium (sometimes shortened to neutrium) is a proposed name for a substance composed purely of neutrons.

The proton–proton chain reaction is one of the two (known) sets of fusion reactions by which stars convert hydrogen to helium.

A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite.

A Cepheid variable (/ˈsɛfiːɪd/ or /ˈsiːfiːɪd/) is a type of star that pulsates radially, varying in both diameter and temperature and producing changes in brightness with a well-defined stable period and amplitude.

The hydrogen anion is a negative ion of hydrogen, H−.

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 mass.

In astrophysics and physical cosmology, Olbers' paradox, named after the German astronomer Heinrich Wilhelm Olbers (1758–1840) and also called the "dark night sky paradox", is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe.

Cosmology (from the Greek κόσμος, kosmos "world" and -λογία, -logia "study of"), is the study of the origin, evolution, and eventual fate of the universe.

An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much higher than normal luminosity over at least some portion – and possibly all – of the electromagnetic spectrum.

The Kelvin–Helmholtz mechanism is an astronomical process that occurs when the surface of a star or a planet cools.

Differential rotation is seen when different parts of a rotating object move with different angular velocities (rates of rotation) at different latitudes and/or depths of the body and/or in time.

Plasma parameters define various characteristics of a plasma, an electrically conductive collection of charged particles that responds collectively to electromagnetic forces.

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun.

TRACE is a high-precision orbit determination and orbit propagation program.

Compton scattering, discovered by Arthur Holly Compton, is the inelastic scattering of a photon by a charged particle, usually an electron.

Angioletta Coradini (1 July 1946 – 5 September 2011) was an Italian astrophysicist, planetary scientist and one of the most important figures in the space sciences in Italy.

In general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer.

Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its origin, structure, evolution, and ultimate fate.

Astronomy & Geophysics, also known as A&G, is a peer-reviewed scientific journal published on behalf of the Royal Astronomical Society by Oxford University Press.

In astronomical spectroscopy, the Gunn–Peterson trough is a feature of the spectra of quasars due to the presence of neutral hydrogen in the Intergalactic Medium (IGM).

Bi-scalar tensor vector gravity theory (BSTV) is an extension of the tensor–vector–scalar gravity theory (TeVeS).

Gustav E. Eberhard (10 August 1867 – 3 January 1940) German astrophysicist.

The Grupo de Astronomía y Ciencias del Espacio (Group of Astronomy and Space Sciences, GACE-UV) is an astrophysics research group, part of the Image Processing Laboratory (IPL) in the University of Valencia.

ICRA, the International Center for Relativistic Astrophysics is an international research institute for relativistic astrophysics and related areas.

Sakurai's Object (V4334 Sgr) is a star in the constellation of Sagittarius.

The standard solar model (SSM) is a mathematical treatment of the Sun as a spherical ball of gas (in varying states of ionisation, with the hydrogen in the deep interior being a completely ionised plasma).

This is a list of black holes (and stars considered probable candidates) organized by size (including black holes of undetermined mass); some items in this list are galaxies or star clusters that are believed to be organized around a black hole.

The Dark Matter Particle Explorer, or DAMPE, is a Chinese Academy of Sciences (CAS) satellite which was launched on 17 December 2015 at 00:12 UTC.

The Innermost stable circular orbit (often called the ISCO) is the smallest orbit in which a test particle can stably orbit a massive object in general relativity.

The source function is a characteristic of a stellar atmosphere, and in the case of no scattering of photons, describes the ratio of the emission coefficient to the absorption coefficient.

Tensor–vector–scalar gravity (TeVeS), developed by Jacob Bekenstein in 2004, is a relativistic generalization of Mordehai Milgrom's Modified Newtonian dynamics (MOND) paradigm.

In physics, optical depth or optical thickness, is the natural logarithm of the ratio of incident to transmitted radiant power through a material, and spectral optical depth or spectral optical thickness is the natural logarithm of the ratio of incident to transmitted spectral radiant power through a material.

Black-body radiation is the type of electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non-reflective body), assumed for the sake of calculations and theory to be held at constant, uniform temperature.

In astrophysics, a polytrope refers to a solution of the Lane–Emden equation in which the pressure depends upon the density in the form where P is pressure, ρ is density and K is a constant of proportionality.

Ofer Lahav is Perren Chair of Astronomy at University College London (UCL).

Cosmogenic nuclides (or cosmogenic isotopes) are rare isotopes created when a high-energy cosmic ray interacts with the nucleus of an in situ Solar System atom, causing nucleons (protons and neutrons) to be expelled from the atom (see cosmic ray spallation).

In astronomy and cosmology, dark fluid is an alternative theory to both dark matter and dark energy and attempts to explain both phenomena in a single framework.

The Instituto de Astrofísica de Andalucía (Institute of Astrophysics of Andalusia, IAA-CSIC) is a research institute funded by the High Council of Scientific Research of the Spanish government Consejo Superior de Investigaciones Científicas (CSIC), and is located in Granada, Andalusia, Spain.

J. Marvin Herndon (born 1944) is an American interdisciplinary scientist, who earned his BA degree in physics in 1970 from the University of California, San Diego and his Ph.

A lead star is a low-metallicity star with an overabundance of lead and bismuth as compared to other products of the S-process.

Scalar–tensor–vector gravity (STVG) is a modified theory of gravity developed by John Moffat, a researcher at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario.