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Topic: Physical constant

Related Topics

Astronomical constant

Planck scale

Bohr magneton

Scientific constants named after people

Planck units

SI

Gravitational constant

Plancks constant

Constant of proportionality

Number

Dimension theory

Coercivity

Magnetic susceptibility

Speed of light

Quantum

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	Physical constant - Wikipedia, the free encyclopedia
		Constants can take many forms: the speed of light in a vacuum signifies a maximum speed limit of the universe; while the fine-structure constant α, which characterizes the interaction between electrons and photons, is dimensionless.
		Unless the system of natural units is used, the numerical values of dimensionful physical constants are artifacts of the unit system used, such as SI or cgs; that is, they are essentially conversion factors of human construct.
		Constants that are independent of systems of units are typically dimensionless numbers, known as fundamental physical constants, and are truly meaningful parameters of nature, not merely human constructs.
	en.wikipedia.org /wiki/Physical_constant (582 words)

	Physical constant: Facts and details from Encyclopedia Topic (Site not responding. Last check: 2007-10-14)
		Plancks constant, denoted h, is a physical constant that is used to describe the sizes of quanta....
		An astronomical constant is a physical constant used in astronomy....
		In physics, the magnetic moment of an object is a vector relating the aligning torque in a magnetic field experienced by the object to the field vector itself....
	www.absoluteastronomy.com /encyclopedia/p/ph/physical_constant.htm (2293 words)

	Fundamental physical constant - Wikipedia, the free encyclopedia
		In physics, fundamental physical constants are, in the strictest sense, physical constants that are independent of systems of units and hence are dimensionless numbers.
		This is accomplished by definiing the units of measurement in such a way that several of the most common physical constants, such as the speed of light, are normalized to unity.
		These constants constrain any plausible fundamental physical theory, which must either be able to produce these values from basic mathematics, or accept these constants as arbitrary.
	en.wikipedia.org /wiki/Fundamental_physical_constant (609 words)

	[No title]
		PHYSICAL CONSTANTS There are a number of physical constants that are used in equations to solve problems in physics.
		Errors may occur because the dimensionality and/or units of the physical constant are not known.
		rho is the density of the fluid and g is the gravitational constant.
	www.cs.umbc.edu /~squire/adaclass/physics1.vu (331 words)

	Connection of Three Major Constants: fine structure constant, number pi and gold ratio. (Site not responding. Last check: 2007-10-14)
		At that, all dimensionless physical constants are very toughly connected among themselves inside own family of dimensionless constants, and their connection with dimensional fundamental physical constants is only consequence, i.e.
		There it is shown that three physical dimensional and two geometrical dimensionless super constants are enough as uniform ontological constant basis for the description of the laws of a nature.
		When accepting of geometrical essence of fine structure constant all the dimensional and the dimensionless parameters, which characterize the microworld and universe are calculable in principle.
	www.laboratory.ru /articl/hypo/ax140e.htm (2287 words)

	Ontolingua Theory PHYSICAL-QUANTITIES
		In engineering analysis, physical quantities such as the length of a beam or the velocity of a body are routinely modeled by variables in equations with numbers as values.
		A physical-quantity is a measure of some quantifiable aspect of the modeled world, such as 'the earth's diameter' (a constant length) and 'the stress in a loaded deformable solid' (a measure of stress, which is a function of three spatial coordinates).
		A physical dimension is a property we associate with physical quantities for purposes of classification or differentiation.
	www-ksl.stanford.edu /htw/dme/thermal-kb-tour/physical-quantities.html (2564 words)

	Unification and distance
		Physical constants like the speed of light and Planck's constant have values that tell us the size or energy where the the observable physics begins to change substantially, and a different way of describing the physics mathematically is called for.
		In elementary particle physics, electromagnetism, the strong and weak nuclear forces are described by a combination of relativity and quantum mechanics, called relativistic quantum field theory.
		The combination of Planck's constant with the speed of light and the electron charge means this coupling constant is telling us about the quantum relativistic physics of electromagnetism, that is, it tells us something about electromagnetism at distance scales where quantum mechanics and special relativity are both important to the physics at the same time.
	superstringtheory.com /experm/exper3.html (1770 words)

	New Quasar Studies Keep Fundamental Physical Constant Constant (ESO Press Release 05/04)
		Detecting or constraining the possible time variations of fundamental physical constants is an important step toward a complete understanding of basic physics and hence the world in which we live.
		Well-known examples are the gravitational constant, which defines the strength of the force acting between two bodies, such as the Earth and the Moon, and the speed of light.
		If the fine-structure constant happens to change over the duration of the light's journey, the energy levels in the atoms would be affected and the wavelengths of the absorption lines would be shifted by different amounts.
	www.eso.org /outreach/press-rel/pr-2004/pr-05-04.html (1733 words)

	constants
		Constants that aren't dimensionless can be regarded as relating one sort of unit to another.
		People who are interested in fundamental physical constants usually start by doing this as much as possible - leaving the dimensionless constants, which are the really interesting ones.
		The electromagnetic coupling constant is just another name for the fine structure constant; it describes the strength of the electromagnetic field.
	math.ucr.edu /home/baez/constants.html (1705 words)

	CE410: Are constants constant?
		Physicists only assume that physical constants have been constant over billions of years.
		The constancy of constants is a conclusion, not an assumption.
		The fine structure constant affects neutron capture rates, which can be measured from products of the Oklo reactor, where a natural nuclear reaction occurred 1,800 million years ago.
	www.talkorigins.org /indexcc/CE/CE410.html (263 words)

	04.18.2005 - Galaxy observations show no change in fundamental physical constant
		The results are being reported today (Monday, April 18) at the annual meeting of the American Physical Society (APS) by astronomer Jeffrey Newman, a Hubble Fellow at Lawrence Berkeley National Laboratory representing DEEP2, a collaboration led by the University of California, Berkeley, and UC Santa Cruz.
		The fine structure constant, one of a handful of pure numbers that occupy a central role in physics, pops up in nearly all equations involving electricity and magnetism, including those describing the emission of electromagnetic waves - light - by atoms.
		The fine structure constant, designated by the Greek letter alpha, is a ratio of other "constants" of nature that, in some theories, could change over cosmic time.
	www.berkeley.edu /news/media/releases/2005/04/18_deep2.shtml (1506 words)

	Physical constants
		There are many physical constants in science, some of the most famous being: Planck's constant, the gravitational constant, and Avogadro's constant (better known as Avogadro's number).
		Constants can take many forms: the Planck length represents a fundamental physical distance; the speed of light in a vacuum signifies a maximum speed limit of the universe; and the fine-structure constant, which characterizes the interaction between electrons and photons, is dimensionless.
		Brought to you by NoChildLeftBehind.com and the Beaches and Towns Network, LLC.
	www.teachtime.com /en/wikipedia/p/ph/physical_constants.html (203 words)

	atomic constant concept from the Astronomy knowledge base (Site not responding. Last check: 2007-10-14)
		It gives a rough measure of the relative importance of relativistic and spin effects in the spectra of atoms., A parameter that measures the strength of the electromagnetic force.
		The fine-structure constant is a combination of other fundamental constants of nature - the electrical charge of the electron, the speed of light, and Planck's constant of quantum mechanics., A coupling constant e
		/ h bar c, approximately equal to 1/137 (where e is the electron charge, h bar is Plancks constant, and c is the speed of light), that measures the strength of the interaction between a charged particle and the electromagnetic field.
	www.site.uottawa.ca:4321 /astronomy/atomicconstant.html (208 words)

	ScienceDaily: New Quasar Studies Keep Fundamental Physical Constant Constant
		Electromagnetism -- Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, which exerts a force on those particles that possess the property of electric charge, and is in turn...
		Astrophysics -- Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature and chemical composition) of astronomical...
		Physical Geology is a market-leading classic that has been used in classrooms for over 20 years.
	www.sciencedaily.com /releases/2004/04/040401080310.htm (2938 words)

	8.11.1 Fundamental Physical Constants (Site not responding. Last check: 2007-10-14)
		The constants used in MOPAC are given in Table 8.40.
		Note: The precision of derived constants should not be used as an indication of their accuracy.
		The uncertainty in the fundamental constants is given in parenthesis after the value.
	home.att.net /~mopacmanual/node574.html (170 words)

	physico chemical constant concept from the Astronomy knowledge base (Site not responding. Last check: 2007-10-14)
		Boltzmann constant (7 facts) (k) - The constant of proportionality relating the mean kinetic energy of an atom to its absolute temperature.
		It is equal to the Avogadro constant divided by the molar volume.
		Stefan-Boltzmann constant (7 facts) (σ) - The constant of proportionality relating the luminosity of a star to its absolute temperature: σ = 5.67 × 10
	www.site.uottawa.ca:4321 /astronomy/physicochemicalconstant.html (284 words)

	New Scientist Breaking News - New twist in wrangle over changing physical constant (Site not responding. Last check: 2007-10-14)
		A new study of distant galaxies is adding a fresh perspective to the debate over whether a fundamental physical constant has actually changed over time.
		He adds that the spectral lines may be faint and can overlap, making it difficult to tell the lines' source, and that astronomers must assume that all of the clouds share the same basic composition.
		And because the average wavelength of the light emitted by the oxygen ions is a direct measurement of alpha, he says, "the fine-structure constant pops out without any interpretation".
	www.newscientist.com /article.ns?id=dn7285 (654 words)

	Physical Constants and Conversion Factors
		Recently new values have been published which are considerably more accurate, except for the gravitational constant, G. For details of these please see Ref. [4] and the NIST website.
		Cohen and B. Taylor, "The 1986 CODATA recommended values of the fundamental physical constants.", J. Res.
		Cohen and B. Taylor, "The 1986 adjustment of the fundamental physical constants", CODATA Bulletin Number 63, (1986); and Rev. Mod.
	newton.ex.ac.uk /research/qsystems/collabs/constants.html (160 words)

	PHYSICAL CONSTANTS AND EVOLUTION OF THE UNIVERSE
		The agreement with the fundamental physics laws is achieved by introducing the evolution of a number of other fundamental constants synchronously with the variation of the speed of light.
		In order the evolution of the speed of light does not lead to the variation of the interaction constants, i.e., to the variation of the atomic spectra, nuclei stability and other regularities, the synchronous variation of a number of fundamental constants are accepted together with the light speed variation.
		The basic difference between cosmology in terms of the hypothesis on the light speed variation is in the fact that the moving force of evolution of the universe in the standard cosmology is the gravitation alone, while in the considered one the phenomenon of the electromagnetic interaction as well.
	www.ldolphin.org /troitskii (6986 words)

	Chapter 3. Planck's Constant
		Therefore, the term, fundamental, universal physical constant of nature, or FUPCON, is a misnomer for constant of proportionality, which, itself, is a misnomer for collection of quantum-attribute factors.
		If we purged our physics books of all mention of Planck's constant, it would not be missed except by those interested in the nostalgic history of quantum physics.
		In the past, whenever Planck's constant showed up in yet another equation that dealt with quantized phenomena, many were quick to state that this reconfirmed the central importance of Planck's constant.
	www.writword.com /unituniv/c03.htm (1146 words)

	ScienceDaily: Galaxy Observations Show No Change In Fundamental Physical Constant
		Their distance from us (7 billion light years or more) means that the light we see today left these galaxies when the universe was less than half as old as it is today.
		New Quasar Studies Keep Fundamental Physical Constant Constant (April 1, 2004) -- Detecting or constraining the possible time variations of fundamental physical constants is an important step toward a complete understanding of basic physics and hence the world in which we live.
		Redshift -- In physics and astronomy, redshift is an observed increase in the wavelength of electromagnetic radiation received by a detector compared to that emitted by the source.
	www.sciencedaily.com /releases/2005/04/050418204410.htm (2751 words)

	A Constant that Isn't Constant
		Quasar spectra recorded at the Keck Observatory in Hawaii imply that a fundamental physical constant may have been increasing slightly over the past six billion years.
		Since the 1930s physicists have discussed whether the constants that appear in the equations for the fundamental laws of physics--such as the speed of light in vacuum and the electron charge--are actually constant.
		John Webb, of the University of New South Wales in Australia, and his colleagues, focused on the fine structure constant, which goes by the Greek letter alpha, because it has no units and is independent of any measurement system.
	focus.aps.org /story/v8/st9 (716 words)

	Measuring the Planck Constant (Site not responding. Last check: 2007-10-14)
		J-s, the Planck constant is a fundamental physical constant used in calculations throughout mathematics and science.
		It improved the uncertainties of several measurements related to the Planck constant such as electron mass, proton mass, and the Avogadro number.
		This voltage was proportional to the Planck constant.
	museum.nist.gov /exhibits/timeline/printerFriendly.cfm?itemId=32 (572 words)

	GNU Scientific Library -- Reference Manual: Physical Constant Examples (Site not responding. Last check: 2007-10-14)
		The following program demonstrates the use of the physical constants in a calculation.
		The average radius of the orbit of Mars is 1.52 astronomical units, and for the orbit of Earth it is 1 astronomical unit (by definition).
		These values are combined with the MKS values of the constants for the speed of light and the length of an astronomical unit to produce a result for the shortest and longest light-travel times in seconds.
	linux.duke.edu /~mstenner/free-docs/gsl-ref-1.0/gsl-ref_472.html (166 words)

	Are natural physical laws constant? (Site not responding. Last check: 2007-10-14)
		But, then, there are other principles that we can control, as in principles of chemical processes, for example; and physical chemical is a beautiful area from which to start, to look at that.
		The development of a sun, a solar system, with 92 known elements, from a simple, fast-rotating sun, is an example of a physical change in the organization of the universe.
		So, what we do, as a matter of practice, we put limits upon our asserted assumptions about the universe, and we reduce the thing to a practical form of statement, about the way we know we can act, in the universe.
	larouchein2004.net /pages/questions/youth/030713ecs003.htm (540 words)

	Define gas constant - a definition from Whatis.com - see also: universal molar gas constant
		The gas constant, also known as the universal molar gas constant, is a physical constant that appears in an equation defining the behavior of a gas under theoretically ideal conditions.
		The gas constant is, by convention, symbolized R.
		The gas constant has been found, by experiment, to have a value of approximately 8.3145 joules per kelvin per mole (J · K
	whatis.techtarget.com /definition/0,,sid9_gci858191,00.html (197 words)

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