269 relations: Acclimatization, Adhesive, Aether (classical element), Aether (mythology), Air embolism, Al-Biruni, Al-Farabi, Altitude sickness, Aluminium, Ancient Greece, Ancient Greek philosophy, Aristotle, Astronomer, Atmosphere, Atmosphere (unit), Atmosphere of Mars, Atmospheric pressure, Atmospheric railway, Atomism, August Toepler, Étienne Tempier, Bar (unit), Barometer, Barotrauma, Bellows, Bishop, Black hole, Black-body radiation, Blaise Pascal, Blasius of Parma, Blood, Boiling point, Brake, Cambridge University Press, Car, Cartesian coordinate system, Cathode ray tube, Cf., Characteristic impedance, Chemical vapor deposition, Classical electromagnetism, Cold cathode, Cold welding, Condemnations of 1210–1277, Configuration space (physics), Consciousness, Cosmic background radiation, Cosmic ray, Coulomb's law, Crookes radiometer, ..., Cryopump, Dark energy, Decompression sickness, Diamagnetism, Dichotomy, Dirac equation, Dirac sea, Donald Hill, Drag (physics), Dry etching, Dynamic pressure, Eardrum, Ebullism, Einstein field equations, Electric displacement field, Electric field, Electric potential, Electromagnetism, Electron microscope, Electron-beam welding, English language, Evangelista Torricelli, Evaporation, Experiment, Extremophile, False vacuum, Field (physics), Flight suit, Fluid mechanics, Flywheel energy storage, Freeze-drying, Friction, Gamma ray, Gaussian units, General relativity, Geometry, Gravitational wave, Graviton, Ground state, Heinrich Geißler, Helium, Helium mass spectrometer, Heritage railway, Hero of Alexandria, Hilbert space, Horror vacui (physics), Hot-filament ionization gauge, Human spaceflight, Hydrogen, Hypoxia (medical), Ibn al-Haytham, Impedance of free space, Incandescent light bulb, Inflation (cosmology), Injector, International System of Units, Interplanetary spaceflight, Interstellar medium, Isaac Newton, Isambard Kingdom Brunel, Jean Buridan, Johann Rafelski, Jupiter, Kalam, Kármán line, Kelvin, Laboratory, Lamb shift, Light, Liquid nitrogen, Liquid-ring pump, Local Group, Low Earth orbit, Lucretius, Luminiferous aether, Lung, Magdeburg hemispheres, Magnetic field, Manifold vacuum, Mathematics in medieval Islam, Matter, McLeod gauge, Mean free path, Mercury (element), Metallurgy, Microorganism, Millimeter of mercury, Molecular beam epitaxy, Momentum, Monthly Notices of the Royal Astronomical Society, Moon, Muʿtazila, Nanometre, Neon, Neutrino, Newcomen atmospheric engine, Number density, Observable universe, Optical coating, Orders of magnitude (pressure), Otto von Guericke, Outer space, Outgassing, Pair production, Palladium, Paramagnetism, Pascal (unit), Paul Dirac, PDF, Permeability (electromagnetism), Permittivity, Philosophy, Photon, Physical vapor deposition, Physics (Aristotle), Pirani gauge, Plato, Pneuma, Pneumatic tube, Popular Science, Positron, Pressure, Pressure measurement, Pulmonary alveolus, QCD vacuum, QED vacuum, Quantum chromodynamics, Quantum electrodynamics, Quantum field theory, Quantum fluctuation, Quantum mechanics, Radiation pressure, Railway air brake, Rarefaction, Refraction, Relative permeability, Relative permittivity, René Descartes, Resistance thermometer, Ricci curvature, Robert Boyle, Robert Hogarth Patterson, Robert Hooke, Roger Bacon, Rotary vane pump, Routledge, Satellite, Scholasticism, Semiconductor device fabrication, Solar sail, Solar wind, Space, Space Shuttle program, Space suit, Space weather, Spacetime, Speed of light, Spontaneous emission, Stanford Encyclopedia of Philosophy, Stationary point, Steam turbine, Stoic physics, Stress–energy tensor, String theory, String theory landscape, Sublimation (phase transition), Submarine, Suction, Sun, Supernatural, Superposition principle, Surface condenser, Surface science, Tape drive, Tardigrade, Temperature, Thermosphere, Thoracic diaphragm, Thought experiment, Titanium, Toepler pump, Torr, Train, Tropical cyclone, U, Ultra-high vacuum, Ultracentrifuge, Uncertainty principle, Unified atomic mass unit, University of Chicago, Vacuum angle, Vacuum arc, Vacuum brake, Vacuum cementing, Vacuum cleaner, Vacuum deposition, Vacuum distillation, Vacuum energy, Vacuum engineering, Vacuum flange, Vacuum flask, Vacuum fryer, Vacuum induction melting, Vacuum interrupter, Vacuum packing, Vacuum permeability, Vacuum permittivity, Vacuum pump, Vacuum servo, Vacuum state, Vacuum tube, Vapor pressure, Vector (mathematics and physics), Virtual particle, Walter Burley, Werner Heisenberg, Weyl tensor, William Henry Pickering, Windscreen wiper. Expand index (219 more) » « Shrink index
Acclimatization or acclimatisation (also called acclimation or acclimatation) is the process in which an individual organism adjusts to a change in its environment (such as a change in altitude, temperature, humidity, photoperiod, or pH), allowing it to maintain performance across a range of environmental conditions.
An adhesive, also known as glue, cement, mucilage, or paste, is any substance applied to one surface, or both surfaces, of two separate items that binds them together and resists their separation.
According to ancient and medieval science, aether (αἰθήρ aithēr), also spelled æther or ether and also called quintessence, is the material that fills the region of the universe above the terrestrial sphere.
In Greek mythology, Aether (Αἰθήρ Aither) was one of the primordial deities.
An air embolism, also known as a gas embolism, is a blood vessel blockage caused by one or more bubbles of air or other gas in the circulatory system.
Abū Rayḥān Muḥammad ibn Aḥmad Al-Bīrūnī (Chorasmian/ابوریحان بیرونی Abū Rayḥān Bērōnī; New Persian: Abū Rayḥān Bīrūnī) (973–1050), known as Al-Biruni (البيروني) in English, was an IranianD.J. Boilot, "Al-Biruni (Beruni), Abu'l Rayhan Muhammad b. Ahmad", in Encyclopaedia of Islam (Leiden), New Ed., vol.1:1236–1238.
Al-Farabi (known in the West as Alpharabius; c. 872 – between 14 December, 950 and 12 January, 951) was a renowned philosopher and jurist who wrote in the fields of political philosophy, metaphysics, ethics and logic.
Altitude sickness, also known as acute mountain sickness (AMS), is a negative health effect of high altitude, caused by acute exposure to low amounts of oxygen at high altitude.
Aluminium or aluminum is a chemical element with symbol Al and atomic number 13.
Ancient Greece was a civilization belonging to a period of Greek history from the Greek Dark Ages of the 13th–9th centuries BC to the end of antiquity (AD 600).
Ancient Greek philosophy arose in the 6th century BC and continued throughout the Hellenistic period and the period in which Ancient Greece was part of the Roman Empire.
Aristotle (Ἀριστοτέλης Aristotélēs,; 384–322 BC) was an ancient Greek philosopher and scientist born in the city of Stagira, Chalkidiki, in the north of Classical Greece.
An astronomer is a scientist in the field of astronomy who concentrates their studies on a specific question or field outside the scope of Earth.
An atmosphere is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body.
The standard atmosphere (symbol: atm) is a unit of pressure defined as.
The atmosphere of the planet Mars is composed mostly of carbon dioxide.
Atmospheric pressure, sometimes also called barometric pressure, is the pressure within the atmosphere of Earth (or that of another planet).
An atmospheric railway uses differential air pressure to provide power for propulsion of a railway vehicle.
Atomism (from Greek ἄτομον, atomon, i.e. "uncuttable", "indivisible") is a natural philosophy that developed in several ancient traditions.
August Joseph Ignaz Toepler (7 September 1836 – 6 March 1912) was a German physicist known for his experiments in electrostatics.
Étienne (Stephen) Tempier (also known as Stephanus of Orleans; died 3 September 1279) was a French bishop of Paris during the 13th century.
The bar is a metric unit of pressure, but is not approved as part of the International System of Units (SI).
A barometer is a scientific instrument used in meteorology to measure atmospheric pressure.
Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with the body, and the surrounding gas or fluid.
A bellows or pair of bellows is a device constructed to furnish a strong blast of air.
A bishop (English derivation from the New Testament of the Christian Bible Greek επίσκοπος, epískopos, "overseer", "guardian") is an ordained, consecrated, or appointed member of the Christian clergy who is generally entrusted with a position of authority and oversight.
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.
Black-body radiation is the thermal 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).
Blaise Pascal (19 June 1623 – 19 August 1662) was a French mathematician, physicist, inventor, writer and Catholic theologian.
Blasius of Parma (Biagio Pelacani da Parma) (c. 1365 – 1416) was an Italian philosopher, mathematician and astrologer.
Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.
The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid and the liquid changes into a vapor.
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system.
Cambridge University Press (CUP) is the publishing business of the University of Cambridge.
A car (or automobile) is a wheeled motor vehicle used for transportation.
A Cartesian coordinate system is a coordinate system that specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular directed lines, measured in the same unit of length.
The cathode ray tube (CRT) is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images.
The abbreviation cf. (short for the confer/conferatur, both meaning "compare") is used in writing to refer the reader to other material to make a comparison with the topic being discussed.
The characteristic impedance or surge impedance (usually written Z0) of a uniform transmission line is the ratio of the amplitudes of voltage and current of a single wave propagating along the line; that is, a wave travelling in one direction in the absence of reflections in the other direction.
Chemical vapor deposition (CVD) is deposition method used to produce high quality, high-performance, solid materials, typically under vacuum.
Classical electromagnetism or classical electrodynamics is a branch of theoretical physics that studies the interactions between electric charges and currents using an extension of the classical Newtonian model.
A cold cathode is a cathode that is not electrically heated by a filament.
Cold welding or contact welding is a solid-state welding process in which joining takes place without fusion/heating at the interface of the two parts to be welded.
The Condemnations at the medieval University of Paris were enacted to restrict certain teachings as being heretical.
In classical mechanics, the parameters that define the configuration of a system are called generalized coordinates, and the vector space defined by these coordinates is called the configuration space of the physical system.
Consciousness is the state or quality of awareness, or, of being aware of an external object or something within oneself.
Cosmic background radiation is electromagnetic radiation from the big bang.
Cosmic rays are high-energy radiation, mainly originating outside the Solar System and even from distant galaxies.
Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attract each other.
The Crookes radiometer, also known as a light mill, consists of an airtight glass bulb, containing a partial vacuum.
A cryopump or a "cryogenic pump" is a vacuum pump that traps gases and vapours by condensing them on a cold surface, but are only effective on some gases.
In physical cosmology and astronomy, dark energy is an unknown form of energy which is hypothesized to permeate all of space, tending to accelerate the expansion of the universe.
Decompression sickness (DCS; also known as divers' disease, the bends, aerobullosis, or caisson disease) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation.
Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force.
A dichotomy is a partition of a whole (or a set) into two parts (subsets).
In particle physics, the Dirac equation is a relativistic wave equation derived by British physicist Paul Dirac in 1928.
The Dirac sea is a theoretical model of the vacuum as an infinite sea of particles with negative energy.
Donald Routledge Hill (August 6, 1922 – May 30, 1994)D.
In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid.
Dry etching refers to the removal of material, typically a masked pattern of semiconductor material, by exposing the material to a bombardment of ions (usually a plasma of reactive gases such as fluorocarbons, oxygen, chlorine, boron trichloride; sometimes with addition of nitrogen, argon, helium and other gases) that dislodge portions of the material from the exposed surface.
Dynamic pressure (sometimes called velocity pressure) is the increase in a moving fluid's pressure over its static value due to motion.
In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear.
Ebullism is the formation of gas bubbles in bodily fluids due to reduced environmental pressure, for example at high altitude.
The Einstein field equations (EFE; also known as Einstein's equations) comprise the set of 10 equations in Albert Einstein's general theory of relativity that describe the fundamental interaction of gravitation as a result of spacetime being curved by mass and energy.
In physics, the electric displacement field, denoted by D, is a vector field that appears in Maxwell's equations.
An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.
An electric potential (also called the electric field potential, potential drop or the electrostatic potential) is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration.
Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.
An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination.
Electron-beam welding (EBW) is a fusion welding process in which a beam of high-velocity electrons is applied to two materials to be joined.
English is a West Germanic language that was first spoken in early medieval England and is now a global lingua franca.
Evangelista Torricelli; 15 October 1608 – 25 October 1647) was an Italian physicist and mathematician, best known for his invention of the barometer, but is also known for his advances in optics and work on the method of indivisibles.
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gaseous phase before reaching its boiling point.
An experiment is a procedure carried out to support, refute, or validate a hypothesis.
An extremophile (from Latin extremus meaning "extreme" and Greek philiā (φιλία) meaning "love") is an organism that thrives in physically or geochemically extreme conditions that are detrimental to most life on Earth.
In quantum field theory, a false vacuum is a hypothetical vacuum that is somewhat, but not entirely, stable.
In physics, a field is a physical quantity, represented by a number or tensor, that has a value for each point in space and time.
A flight suit is a full-body garment, worn while flying aircraft such as military airplanes, gliders and helicopters.
Fluid mechanics is a branch of physics concerned with the mechanics of fluids (liquids, gases, and plasmas) and the forces on them.
Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy.
Freeze drying, also known as lyophilisation or cryodessication, is a low temperature dehydration process which involves freezing the product, lowering pressure, then removing the ice by sublimation.
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
A gamma ray or gamma radiation (symbol γ or \gamma), is penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei.
Gaussian units constitute a metric system of physical units.
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.
Geometry (from the γεωμετρία; geo- "earth", -metron "measurement") is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space.
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.
In theories of quantum gravity, the graviton is the hypothetical elementary particle that mediates the force of gravity.
The ground state of a quantum mechanical system is its lowest-energy state; the energy of the ground state is known as the zero-point energy of the system.
Johann Heinrich Wilhelm Geißler (26 May 1814 in Igelshieb – 24 January 1879) was a skilled glassblower and physicist, famous for his invention of the Geissler tube, made of glass and used as a low pressure gas-discharge tube.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
A helium mass spectrometer is an instrument commonly used to detect and locate small leaks.
A heritage railway is a railway operated as living history to re-create or preserve railway scenes of the past.
Hero of Alexandria (ἭρωνGenitive: Ἥρωνος., Heron ho Alexandreus; also known as Heron of Alexandria; c. 10 AD – c. 70 AD) was a mathematician and engineer who was active in his native city of Alexandria, Roman Egypt.
The mathematical concept of a Hilbert space, named after David Hilbert, generalizes the notion of Euclidean space.
In physics, horror vacui, or plenism, is commonly stated as "Nature abhors a vacuum".
The hot-filament ionization gauge, sometimes called a hot-filament gauge or hot-cathode gauge, is the most widely used low-pressure (vacuum) measuring device for the region from 10−3 to 10−10 Torr.
Human spaceflight (also referred to as crewed spaceflight or manned spaceflight) is space travel with a crew or passengers aboard the spacecraft.
Hydrogen is a chemical element with symbol H and atomic number 1.
Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level.
Hasan Ibn al-Haytham (Latinized Alhazen; full name أبو علي، الحسن بن الحسن بن الهيثم) was an Arab mathematician, astronomer, and physicist of the Islamic Golden Age.
The impedance of free space,, is a physical constant relating the magnitudes of the electric and magnetic fields of electromagnetic radiation travelling through free space.
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light (incandescence).
In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe.
A steam injector is typically used to deliver cold water to a boiler against its own pressure using its own live or exhaust steam, replacing any mechanical pump.
The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.
Interplanetary spaceflight or interplanetary travel is travel between planets, usually within a single planetary system.
In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy.
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, astronomer, theologian, author and physicist (described in his own day as a "natural philosopher") who is widely recognised as one of the most influential scientists of all time, and a key figure in the scientific revolution.
Isambard Kingdom Brunel (9 April 1806 – 15 September 1859), was an English mechanical and civil engineer who is considered "one of the most ingenious and prolific figures in engineering history", "one of the 19th-century engineering giants", and "one of the greatest figures of the Industrial Revolution, changed the face of the English landscape with his groundbreaking designs and ingenious constructions".
Jean Buridan (Latin: Johannes Buridanus; –) was an influential 14th century French philosopher.
Johann Rafelski (born 19 May 1950) is a German-American theoretical physicist.
Jupiter is the fifth planet from the Sun and the largest in the Solar System.
ʿIlm al-Kalām (عِلْم الكَلام, literally "science of discourse"),Winter, Tim J. "Introduction." Introduction.
The Kármán line, or Karman line, lies at an altitude of above Earth's sea level and commonly represents the boundary between Earth's atmosphere and outer space.
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 laboratory (informally, lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed.
In physics, the Lamb shift, named after Willis Lamb, is a difference in energy between two energy levels 2S1/2 and 2P1/2 (in term symbol notation) of the hydrogen atom which was not predicted by the Dirac equation, according to which these states should have the same energy.
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.
Liquid nitrogen is nitrogen in a liquid state at an extremely low temperature.
A liquid-ring pump is a rotating positive-displacement pump.
The Local Group is the galaxy group that includes the Milky Way.
A low Earth orbit (LEO) is an orbit around Earth with an altitude of or less, and with an orbital period of between about 84 and 127 minutes.
Titus Lucretius Carus (15 October 99 BC – c. 55 BC) was a Roman poet and philosopher.
In the late 19th century, luminiferous aether or ether ("luminiferous", meaning "light-bearing"), was the postulated medium for the propagation of light.
The lungs are the primary organs of the respiratory system in humans and many other animals including a few fish and some snails.
The Magdeburg hemispheres are a pair of large copper hemispheres, with mating rims.
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere.
Mathematics during the Golden Age of Islam, especially during the 9th and 10th centuries, was built on Greek mathematics (Euclid, Archimedes, Apollonius) and Indian mathematics (Aryabhata, Brahmagupta).
In the classical physics observed in everyday life, matter is any substance that has mass and takes up space by having volume.
A McLeod gauge is a scientific instrument used to measure very low pressures, down to 10−6 Torr.
In physics, the mean free path is the average distance traveled by a moving particle (such as an atom, a molecule, a photon) between successive impacts (collisions), which modify its direction or energy or other particle properties.
Mercury is a chemical element with symbol Hg and atomic number 80.
Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are called alloys.
A microorganism, or microbe, is a microscopic organism, which may exist in its single-celled form or in a colony of cells. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from 6th century BC India and the 1st century BC book On Agriculture by Marcus Terentius Varro. Microbiology, the scientific study of microorganisms, began with their observation under the microscope in the 1670s by Antonie van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera and anthrax. Microorganisms include all unicellular organisms and so are extremely diverse. Of the three domains of life identified by Carl Woese, all of the Archaea and Bacteria are microorganisms. These were previously grouped together in the two domain system as Prokaryotes, the other being the eukaryotes. The third domain Eukaryota includes all multicellular organisms and many unicellular protists and protozoans. Some protists are related to animals and some to green plants. Many of the multicellular organisms are microscopic, namely micro-animals, some fungi and some algae, but these are not discussed here. They live in almost every habitat from the poles to the equator, deserts, geysers, rocks and the deep sea. Some are adapted to extremes such as very hot or very cold conditions, others to high pressure and a few such as Deinococcus radiodurans to high radiation environments. Microorganisms also make up the microbiota found in and on all multicellular organisms. A December 2017 report stated that 3.45 billion year old Australian rocks once contained microorganisms, the earliest direct evidence of life on Earth. Microbes are important in human culture and health in many ways, serving to ferment foods, treat sewage, produce fuel, enzymes and other bioactive compounds. They are essential tools in biology as model organisms and have been put to use in biological warfare and bioterrorism. They are a vital component of fertile soils. In the human body microorganisms make up the human microbiota including the essential gut flora. They are the pathogens responsible for many infectious diseases and as such are the target of hygiene measures.
A millimeter of mercury is a manometric unit of pressure, formerly defined as the extra pressure generated by a column of mercury one millimetre high and now defined as precisely pascals.
Molecular beam epitaxy (MBE) is an epitaxy method for thin-film deposition of single crystals.
In Newtonian mechanics, linear momentum, translational momentum, or simply momentum (pl. momenta) is the product of the mass and velocity of an object.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
The Moon is an astronomical body that orbits planet Earth and is Earth's only permanent natural satellite.
Muʿtazila (المعتزلة) is a rationalist school of Islamic theology"", Encyclopaedia Britannica.
The nanometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American spelling) is a unit of length in the metric system, equal to one billionth (short scale) of a metre (m).
Neon is a chemical element with symbol Ne and atomic number 10.
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.
The atmospheric engine was invented by Thomas Newcomen in 1712, and is often referred to simply as a Newcomen engine.
In physics, astronomy, chemistry, biology and geography, number density (symbol: n or ρN) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number density, two-dimensional areal number density, or one-dimensional line number density.
The observable universe is a spherical region of the Universe comprising all matter that can be observed from Earth at the present time, because electromagnetic radiation from these objects has had time to reach Earth since the beginning of the cosmological expansion.
An optical coating is one or more thin layers of material deposited on an optical component such as a lens or mirror, which alters the way in which the optic reflects and transmits light.
This is a tabulated listing of the orders of magnitude in relation to pressure expressed in pascals.
Otto von Guericke (originally spelled Gericke,; November 20, 1602 – May 11, 1686 (Julian calendar); November 30, 1602 – May 21, 1686 (Gregorian calendar)) was a German scientist, inventor, and politician.
Outer space, or just space, is the expanse that exists beyond the Earth and between celestial bodies.
Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen or absorbed in some material.
Pair production is the creation of an elementary particle and its antiparticle from a neutral boson.
Palladium is a chemical element with symbol Pd and atomic number 46.
Paramagnetism is a form of magnetism whereby certain materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field.
The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength.
Paul Adrien Maurice Dirac (8 August 1902 – 20 October 1984) was an English theoretical physicist who is regarded as one of the most significant physicists of the 20th century.
The Portable Document Format (PDF) is a file format developed in the 1990s to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.
In electromagnetism, permeability is the measure of the ability of a material to support the formation of a magnetic field within itself.
In electromagnetism, absolute permittivity, often simply called permittivity, usually denoted by the Greek letter ε (epsilon), is the measure of resistance that is encountered when forming an electric field in a particular medium.
Philosophy (from Greek φιλοσοφία, philosophia, literally "love of wisdom") is the study of general and fundamental problems concerning matters such as existence, knowledge, values, reason, mind, and language.
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).
Physical vapor deposition (PVD) describes a variety of vacuum deposition methods which can be used to produce thin films and coatings.
The Physics (Greek: Φυσικὴ ἀκρόασις Phusike akroasis; Latin: Physica, or Naturalis Auscultationes, possibly meaning "lectures on nature") is a named text, written in ancient Greek, collated from a collection of surviving manuscripts known as the Corpus Aristotelicum because attributed to the 4th-century BC philosopher, teacher, and mentor of Macedonian rulers, Aristotle.
The Pirani gauge is a robust thermal conductivity gauge used for the measurement of the pressures in vacuum systems.
Plato (Πλάτων Plátōn, in Classical Attic; 428/427 or 424/423 – 348/347 BC) was a philosopher in Classical Greece and the founder of the Academy in Athens, the first institution of higher learning in the Western world.
Pneuma (πνεῦμα) is an ancient Greek word for "breath", and in a religious context for "spirit" or "soul".
Pneumatic tubes (or capsule pipelines; also known as pneumatic tube transport or PTT) are systems that propel cylindrical containers through networks of tubes by compressed air or by partial vacuum.
Popular Science (also known as PopSci) is an American quarterly magazine carrying popular science content, which refers to articles for the general reader on science and technology subjects.
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron.
Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
Pressure measurement is the analysis of an applied force by a fluid (liquid or gas) on a surface.
A pulmonary alveolus (plural: alveoli, from Latin alveolus, "little cavity") is a hollow cavity found in the lung parenchyma, and is the basic unit of ventilation.
Th Quantum Chromodynamic Vacuum or QCD vacuum is the vacuum state of quantum chromodynamics (QCD).
The Quantum Electrodynamic Vacuum or QED vacuum is the field-theoretic vacuum of quantum electrodynamics.
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.
In particle physics, quantum electrodynamics (QED) is the relativistic quantum field theory of electrodynamics.
In theoretical physics, quantum field theory (QFT) is the theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics.
In quantum physics, a quantum fluctuation (or vacuum state fluctuation or vacuum fluctuation) is the temporary change in the amount of energy in a point in space, as explained in Werner Heisenberg's uncertainty principle.
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
Radiation pressure is the pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field.
A railway air brake is a railway brake power braking system with compressed air as the operating medium.
Rarefaction is the reduction of an item's density, the opposite of compression.
Refraction is the change in direction of wave propagation due to a change in its transmission medium.
In multiphase flow in porous media, the relative permeability of a phase is a dimensionless measure of the effective permeability of that phase.
The relative permittivity of a material is its (absolute) permittivity expressed as a ratio relative to the permittivity of vacuum.
René Descartes (Latinized: Renatus Cartesius; adjectival form: "Cartesian"; 31 March 1596 – 11 February 1650) was a French philosopher, mathematician, and scientist.
Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature.
In differential geometry, the Ricci curvature tensor, named after Gregorio Ricci-Curbastro, represents the amount by which the volume of a small wedge of a geodesic ball in a curved Riemannian manifold deviates from that of the standard ball in Euclidean space.
Robert Boyle (25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, and inventor.
Robert Hogarth Patterson (1821–1886) was a Scottish journalist and author.
Robert Hooke FRS (– 3 March 1703) was an English natural philosopher, architect and polymath.
Roger Bacon (Rogerus or Rogerius Baconus, Baconis, also Rogerus), also known by the scholastic accolade Doctor, was an English philosopher and Franciscan friar who placed considerable emphasis on the study of nature through empiricism.
A rotary vane pump is a positive-displacement pump that consists of vanes mounted to a rotor that rotates inside of a cavity.
Routledge is a British multinational publisher.
In the context of spaceflight, a satellite is an artificial object which has been intentionally placed into orbit.
Scholasticism is a method of critical thought which dominated teaching by the academics ("scholastics", or "schoolmen") of medieval universities in Europe from about 1100 to 1700, and a program of employing that method in articulating and defending dogma in an increasingly pluralistic context.
Semiconductor device fabrication is the process used to create the integrated circuits that are present in everyday electrical and electronic devices.
Solar sails (also called light sails or photon sails) are a proposed method of spacecraft propulsion using radiation pressure exerted by sunlight on large mirrors.
The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona.
Space is the boundless three-dimensional extent in which objects and events have relative position and direction.
The Space Shuttle program was the fourth human spaceflight program carried out by the National Aeronautics and Space Administration (NASA), which accomplished routine transportation for Earth-to-orbit crew and cargo from 1981 to 2011.
A space suit is a garment worn to keep a human alive in the harsh environment of outer space, vacuum and temperature extremes.
Space weather is a branch of space physics and aeronomy concerned with the time varying conditions within the Solar System, including the solar wind, emphasizing the space surrounding the Earth, including conditions in the magnetosphere, ionosphere, thermosphere, and exosphere.
In physics, spacetime is any mathematical model that fuses the three dimensions of space and the one dimension of time into a single four-dimensional continuum.
The speed of light in vacuum, commonly denoted, is a universal physical constant important in many areas of physics.
Spontaneous emission is the process in which a quantum mechanical system (such as an atom, molecule or subatomic particle) transitions from an excited energy state to a lower energy state (e.g., its ground state) and emits a quantum in the form of a photon.
The Stanford Encyclopedia of Philosophy (SEP) combines an online encyclopedia of philosophy with peer-reviewed publication of original papers in philosophy, freely accessible to Internet users.
In mathematics, particularly in calculus, a stationary point or critical point of a differentiable function of one variable is a point on the graph of the function where the function's derivative is zero.
A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft.
Stoic physics is the natural philosophy adopted by the Stoic philosophers of ancient Greece and Rome used to explain the natural processes at work in the universe.
The stress–energy tensor (sometimes stress–energy–momentum tensor or energy–momentum tensor) is a tensor quantity in physics that describes the density and flux of energy and momentum in spacetime, generalizing the stress tensor of Newtonian physics.
In physics, string theory is a theoretical framework in which the point-like particles of particle physics are replaced by one-dimensional objects called strings.
The string theory landscape refers to the collection of possible false vacua in string theory,The number of metastable vacua is not known exactly, but commonly quoted estimates are of the order 10500.
Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.
A submarine (or simply sub) is a watercraft capable of independent operation underwater.
Suction is the flow of a fluid into a partial vacuum, or region of low pressure.
The Sun is the star at the center of the Solar System.
The supernatural (Medieval Latin: supernātūrālis: supra "above" + naturalis "natural", first used: 1520–1530 AD) is that which exists (or is claimed to exist), yet cannot be explained by laws of nature.
In physics and systems theory, the superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually.
A surface condenser is a commonly used term for a water-cooled shell and tube heat exchanger installed on the exhaust steam from a steam turbine in thermal power stations.
Surface science is the study of physical and chemical phenomena that occur at the interface of two phases, including solid–liquid interfaces, solid–gas interfaces, solid–vacuum interfaces, and liquid–gas interfaces.
A tape drive is a data storage device that reads and writes data on a magnetic tape.
Tardigrades (also known colloquially as water bears, or moss piglets) are water-dwelling, eight-legged, segmented micro-animals.
Temperature is a physical quantity expressing hot and cold.
The thermosphere is the layer of the Earth's atmosphere directly above the mesosphere and below the exosphere.
For other uses, see Diaphragm (disambiguation). The thoracic diaphragm, or simply the diaphragm (partition), is a sheet of internal skeletal muscle in humans and other mammals that extends across the bottom of the thoracic cavity.
A thought experiment (Gedankenexperiment, Gedanken-Experiment or Gedankenerfahrung) considers some hypothesis, theory, or principle for the purpose of thinking through its consequences.
Titanium is a chemical element with symbol Ti and atomic number 22.
A Toepler pump is a form of mercury piston pump, invented by August Toepler in 1850.
The torr (symbol: Torr) is a unit of pressure based on an absolute scale, now defined as exactly of a standard atmosphere (101.325 kPa).
A train is a form of transport consisting of a series of connected vehicles that generally runs along a rail track to transport cargo or passengers.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain.
U (named u, plural ues) is the 21st letter and the fifth vowel in the ISO basic Latin alphabet.
Ultra-high vacuum (UHV) is the vacuum regime characterised by pressures lower than about 10−7 pascal or 100 nanopascals (10−9 mbar, ~10−9 torr).
The ultracentrifuge is a centrifuge optimized for spinning a rotor at very high speeds, capable of generating acceleration as high as (approx.). There are two kinds of ultracentrifuges, the preparative and the analytical ultracentrifuge.
In quantum mechanics, the uncertainty principle (also known as Heisenberg's uncertainty principle) is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position x and momentum p, can be known.
The unified atomic mass unit or dalton (symbol: u, or Da) is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic mass).
The University of Chicago (UChicago, U of C, or Chicago) is a private, non-profit research university in Chicago, Illinois.
In quantum gauge theories, in the Hamiltonian formulation (Hamiltonian system), the wave function is a functional of the gauge connection \,A and matter fields \,\phi.
A vacuum arc can arise when the surfaces of metal electrodes in contact with a good vacuum begin to emit electrons either through heating (thermionic emission) or in an electric field that is sufficient to cause field electron emission.
The vacuum brake is a braking system employed on trains and introduced in the mid-1860s.
Vacuum cementing or vacuum welding is the natural process of solidifying small objects in a hard vacuum.
A vacuum cleaner, also known as a sweeper or hoover, is a device that uses an air pump (a centrifugal fan in all but some of the very oldest models), to create a partial vacuum to suck up dust and dirt, usually from floors, and from other surfaces such as upholstery and draperies.
Vacuum deposition is a family of processes used to deposit layers of material atom-by-atom or molecule-by-molecule on a solid surface.
Vacuum distillation is a method of distillation performed under reduced pressure.
Vacuum energy is an underlying background energy that exists in space throughout the entire Universe.
Vacuum engineering deals with technological processes and equipment that use vacuum to achieve better results than those run under atmospheric pressure.
A vacuum flange is a flange at the end of a tube used to connect vacuum chambers, tubing and vacuum pumps to each other.
A vacuum flask (also known as a Dewar flask, Dewar bottle or thermos) is an insulating storage vessel that greatly lengthens the time over which its contents remain hotter or cooler than the flask's surroundings.
A vacuum fryer is a deep-frying device housed inside a vacuum chamber.
Vacuum induction melting (VIM) utilizes electric currents to melt metal within a vacuum.
In electrical engineering, a vacuum interrupter is a switch which uses electrical contacts in a vacuum.
Vacuum packing is a method of packaging that removes air from the package prior to sealing.
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.
The physical constant (pronounced as "epsilon nought"), commonly called the vacuum permittivity, permittivity of free space or electric constant, is an ideal, (baseline) physical constant, which is the value of the absolute dielectric permittivity of classical vacuum.
A vacuum pump is a device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum.
A vacuum servo is a component used on motor vehicles in their braking system, to provide assistance to the driver by decreasing the braking effort.
In quantum field theory, the quantum vacuum state (also called the quantum vacuum or vacuum state) is the quantum state with the lowest possible energy.
In electronics, a vacuum tube, an electron tube, or just a tube (North America), or valve (Britain and some other regions) is a device that controls electric current between electrodes in an evacuated container.
Vapor pressure or equilibrium vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.
When used without any further description, vector usually refers either to.
In physics, a virtual particle is a transient fluctuation that exhibits some of the characteristics of an ordinary particle, but whose existence is limited by the uncertainty principle.
Walter Burley (or Burleigh) (c. 1275–1344/5) was a medieval English scholastic philosopher and logician with at least 50 works attributed to him.
Werner Karl Heisenberg (5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the key pioneers of quantum mechanics.
In differential geometry, the Weyl curvature tensor, named after Hermann Weyl, is a measure of the curvature of spacetime or, more generally, a pseudo-Riemannian manifold.
William Henry Pickering (February 15, 1858 – January 16, 1938) was an American astronomer.
A windscreen wiper or windshield wiper (American English) is a device used to remove rain, snow, ice and debris from a windscreen or windshield.
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