superluminal

 Faster-than-light (also FTL, superluminal or supercausal) travel and communication are the conjectural propagation of matter or information faster than the speed of light (c). The special theory of relativity implies that only particles with zero rest mass (i.e., photons) may travel at the speed of light, and that nothing may travel faster.

microgilbert

 

The gilbert (Symbol: Gb) is an obsolete unit used in practical cgs and emu cgs systems to measure magnetization.^[1] The unit is named for English physicist William Gilbert. A microgilbert is one millionth of a gilbert.

Hysteresis

 Hysteresis is the dependence of the state of a system on its history. For example, a magnet may have more than one possible magnetic moment in a given magnetic field, depending on how the field changed in the past.

 

diopter

 diopter, in optics, unit of magnifying power of a lens or lens system.

 

Siping

 

Siping is a process of cutting thin slits across a rubber surface to improve traction in wet or icy conditions.

Siping was invented and patented in 1923 under the name of John F. Sipe. The story told on various websites is that, in the 1920s, Sipe worked in a slaughterhouse and grew tired of slipping on the wet floors. He found that cutting slits in the tread on the bottoms of his shoes provided better traction than the uncut tread. Another story is that he was a deckhand and wanted to avoid slipping on a wet deck. 

 

 A tire with ziggy-zag sipes.

Paramagnetism

 Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field.

 

 

strangelet

A strangelet is a hypothetical particle consisting of a bound state of roughly equal numbers of up, down, and strange quarks. An equivalent description is that a strangelet is a small fragment of strange matter, small enough to be considered a particle.

baryogenesis

In physical cosmology, baryogenesis is the generic term for hypothetical physical processes that produced an asymmetry between baryons and antibaryons in the very early universe, resulting in the substantial amounts of residual matter that make up the universe today.

Baryogenesis theories (the most important being electroweak baryogenesis and GUT baryogenesis) employ sub-disciplines of physics such as quantum field theory, and statistical physics, to describe such possible mechanisms. The fundamental difference between baryogenesis theories is the description of the interactions between fundamental particles.

The next step after baryogenesis is the much better understood Big Bang nucleosynthesis, during which light atomic nuclei began to form.

space roar

The space roar is a radio signal from outer space. Discovered by NASA's Alan Kogut and his team, the announcement was made at the 213th meeting of the American Astronomical Society on January 7, 2009. Described as a loud hiss, the team discovered the signal while trying to find traces of heat from first generation stars using an ARCADE radiometer. This instrument is designed to detect radiation at centimeter wavelengths. Though signals from radio galaxies have been detected before, the "space roar" sounds six times louder than what is predicted from those sources. Scientists have yet to explain its source. NASA scientists have currently ruled out primordial stars and all other known radio sources. The roar currently limits the study of the universe's earliest stars. In 2011, the ARCADE 2 researchers reported, "Correcting for instrumental systematic errors in measurements such as ARCADE 2 is always a primary concern. We emphasize that we detect residual emission at 3 GHz with the ARCADE 2 data, but the result is also independently detected by a combination of low-frequency data and FIRAS."

quadrature

quadrature (plural quadratures)

1. the process of making something square; squaring
2. (mathematics) [1]  [quotations ▼]
3. (astronomy) a situation in which three celestial bodies form a right-angled triangle, the observer being located at the right angle

   When the Moon is in quadrature, it appears in the sky as a half-moon.

4. (physics) the condition in which the phase angle between two alternating quantities is 90°
5. (art) A painting painted on a wooden panel

metastable

metastable (not comparable)

1. (physics, chemistry) Of or pertaining to a physical or chemical state that is relatively long-lived, but may decay to a lower energy state when slightly perturbed or through a quantum transition.

Metastability describes the behaviour of certain physical systems that can exist in long lived states that are less stable than the system's most stable state.

The parameters of excited systems may reach and hold stationary values (a metastable state). But metastable states have finite lifetimes. After a (potentially very long) period of time, spontaneously or under an external action, the characteristic parameters of the state change again to relax to a more stable state.

Aten

The Aten asteroids are a group of near-Earth asteroids, named after the first of the group to be discovered (2062 Aten, discovered January 7, 1976, by Eleanor F. Helin). They are defined by having semi-major axes of less than one astronomical unit (the distance from the Earth to the Sun). Because asteroids' orbits can be highly eccentric, an Aten orbit need not be entirely contained within Earth's orbit; in fact, nearly all known Aten asteroids have their aphelion greater than one AU even though their semi-major axis is less than one AU. Observation of objects inferior to the Earth's orbit is difficult and may be the cause of some bias in the apparent preponderance of eccentric Atens.
Asteroids that have their aphelion entirely within the Earth's orbit are known as Apohele asteroids, or alternatively as Inner Earth Objects (IEOs) or Atira asteroids. Apoheles are traditionally treated as a subclass of Atens, but sometimes are separated. As of August 2012, there are only eleven known Apoheles, and 716 more known Aten asteroids. The smallest aphelion is that of 2008 EB₂₆), at 0.804 AU. The shortest semi-major axis for any known Aten asteroid is that of another Apohele, 2007 EA₃₂), at 0.550 AU.

contrition

contrition

1. The state of being contrite; sincere penitence or remorse.
2. The act of grinding or rubbing to powder; attrition; friction; rubbing.

spaghettification

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 gravitational field, and is caused by extreme tidal forces. In the most extreme cases, near black holes, the stretching is so powerful that no object can withstand it, no matter how strong its components. Within a small region the horizontal compression balances the vertical stretching so that small objects being spaghettified experience no net change in volume.

In his book A Brief History of Time (1988), Stephen Hawking describes the flight of a fictional astronaut who, passing within a black hole's event horizon, is "stretched like spaghetti" by the gravitational gradient (difference in strength) from head to toe. However, the term "spaghettification" was established well before this; Nigel Calder, for example, uses it in his book The Key to the Universe: A Report on the New Physics (Viking Press, 1977), a companion to a one-off BBC TV documentary: The Key to the Universe.

anisotropic

anisotropic (comparative more anisotropic, superlative most anisotropic)

1. (physics) Having properties that differ according to the direction of measurement; exhibiting anisotropy.

   The crystal has an anisotropic structure, as it is stronger along its length than laterally.

orthohydrogen

Each hydrogen molecule (H₂) consists of two hydrogen atoms linked by a covalent bond. If we neglect the small proportion of deuterium and tritium which may be present, each hydrogen atom consists of one proton and one electron. Each proton has an associated magnetic moment, which is associated with the proton's spin of 1/2. In the H₂ molecule, the spins of the two hydrogen nuclei (protons) couple to form a triplet state known as orthohydrogen, and a singlet state known as parahydrogen.

Precession

Precession is a change in the orientation of the rotational axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle (nutation) is constant. In physics, there are two types of precession: torque-free and torque-induced.

In astronomy, "precession" refers to any of several slow changes in an astronomical body's rotational or orbital parameters, and especially to the Earth's precession of the equinoxes. See Precession (astronomy).

polywell

A polywell device is a type of fusion reactor that was originated by Robert Bussard under a U.S. Navy research contract. It traps electrons in a magnetic confinement inside its hollow center. The negatively charged electrons then accelerate positively charged ions for the purpose of achieving inertial electrostatic confinement fusion. The polywell device can trace its development to the ideas behind the Farnsworth-Hirsch Fusor. Bussard theorized that this device could potentially generate net energy production and thus become a source for electric power.

ergosphere

The ergosphere is a region located outside a rotating black hole. Its name is derived from the Greek word ergon, which means “work”. It received this name because it is theoretically possible to extract energy and mass from the black hole in this region. The radius of ergosphere at equator corresponds to Schwarzschild radius of non-rotating black hole and with minimum radius at poles (down to a half of Schwarzschild radius for maximally rotating black hole)

The ergosphere is ellipsoidal in shape and is situated so that at the poles of a rotating black hole it touches the event horizon and stretches out to a distance that is equal to the radius of the event horizon. Within the ergosphere, spacetime is dragged along in the direction of the rotation of the black hole at a speed greater than the local speed of light in relation to the rest of the universe. This process is known as the Lense-Thiring effect or frame-dragging. Because of this dragging effect, objects within the ergosphere are not stationary with respect to the rest of the universe unless they travel faster than the speed of light, which is impossible based on the laws of physics. But in truth, particles are not moving with that speed, it is the spacetime of the ergosphere that moves with a speed higher than the speed of light. A suspended plumb, held stationary outside the ergosphere, will experience infinite/diverging radial pull as it approaches the static limit. At some point it will start to fall, resulting in gravitomagnetically induced spinward motion. Another result of this dragging of space is the existence of negative energies within the ergosphere.

barn

A barn (symbol b) is a unit of area. Originally used in nuclear physics for expressing the cross sectional area of nuclei and nuclear reactions, today it is used in all fields of high energy physics to express the cross sections of any scattering process. A barn is defined as 10 m² (100 fm) and is approximately the cross sectional area of a uranium nucleus. The barn is also the unit of area used in nuclear quadrupole resonance and nuclear magnetic resonance to quantify the interaction of a nucleus with an electric field gradient. While the barn is not an SI unit, it is accepted for use with the SI due to its continued use in particle physics. It is one of the very few units which are accepted to be used with SI units, and one of the most recent units to have been established (cf. the knot and the bar, other non-SI units acceptable in limited circumstances).

Two related units are the outhouse (10⁻³⁴ m, or 1 μb) and the shed (10⁻⁵² m, or 1 yb), although these are rarely used in practice.