X-ray binaryX-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the donor (usually a relatively normal star), to the other component, called the accretor, which is either a neutron star or black hole. The infalling matter releases gravitational potential energy, up to 30 percent of its rest mass, as X-rays. (Hydrogen fusion releases only about 0.7 percent of rest mass.
Radio astronomyRadio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers.
Warm–hot intergalactic mediumThe warm–hot intergalactic medium (WHIM) is the sparse, warm-to-hot (105 to 107 K) plasma that cosmologists believe to exist in the spaces between galaxies and to contain 40–50% of the baryonic 'normal matter' in the universe at the current epoch. The WHIM can be described as a web of hot, diffuse gas stretching between galaxies, and consists of plasma, as well as atoms and molecules, in contrast to dark matter. The WHIM is a proposed solution to the missing baryon problem, where the observed amount of baryonic matter does not match theoretical predictions from cosmology.
Future generationsFuture generations are cohorts of hypothetical people not yet born. Future generations are contrasted with current and past generations, and evoked in order to encourage thinking about intergenerational equity. The moral patienthood of future generations has been argued for extensively among philosophers, and is thought of as an important, neglected cause by the effective altruism community. The term is often used in describing the conservation or preservation of cultural heritage or natural heritage.
ObservableIn physics, an observable is a physical property or physical quantity that can be measured. Examples include position and momentum. In systems governed by classical mechanics, it is a real-valued "function" on the set of all possible system states. In quantum physics, it is an operator, or gauge, where the property of the quantum state can be determined by some sequence of operations. For example, these operations might involve submitting the system to various electromagnetic fields and eventually reading a value.
Faraday rotatorA Faraday rotator is a polarization rotator based on the Faraday effect, a magneto-optic effect involving transmission of light through a material when a longitudinal static magnetic field is present. The state of polarization (such as the axis of linear polarization or the orientation of elliptical polarization) is rotated as the wave traverses the device, which is explained by a slight difference in the phase velocity between the left and right circular polarizations.
Lovell TelescopeThe Lovell Telescope (ˈlʌvəl ) is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire, in the north-west of England. When construction was finished in 1957, the telescope was the largest steerable dish radio telescope in the world at 76.2 m (250 ft) in diameter; it is now the third-largest, after the Green Bank telescope in West Virginia, United States, and the Effelsberg telescope in Germany.
Michael FaradayMichael Faraday (ˈfærədeɪ,_-di; 22 September 1791 – 25 August 1867) was an English scientist who contributed to the study of electromagnetism and electrochemistry. His main discoveries include the principles underlying electromagnetic induction, diamagnetism and electrolysis. Although Faraday received little formal education, he was one of the most influential scientists in history. It was by his research on the magnetic field around a conductor carrying a direct current that Faraday established the concept of the electromagnetic field in physics.
Intergenerational equityIntergenerational equity in economic, psychological, and sociological contexts, is the idea of fairness or justice between generations. The concept can be applied to fairness in dynamics between children, youth, adults, and seniors. It can also be applied to fairness between generations currently living and future generations. Conversations about intergenerational equity occur across several fields. It is often discussed in public economics, especially with regard to transition economics, social policy, and government budget-making.
Homopolar motorA homopolar motor is a direct current electric motor with two magnetic poles, the conductors of which always cut unidirectional lines of magnetic flux by rotating a conductor around a fixed axis so that the conductor is at right angles to a static magnetic field. The resulting force being continuous in one direction, the homopolar motor needs no commutator but still requires slip rings. The name homopolar indicates that the electrical polarity of the conductor and the magnetic field poles do not change (i.
