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/Home/Sciences/Physical Science/Physics/Constants Scaling the universe: Gravitational lenses and the Hubble constant -- Myers 96 (8): 4236 -- Proceedings of the National Academy of Sciences Votes:0 This Article Abstract Full Text (PDF) Data Supplement Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via ISI Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Myers, S. T. Search for Related Content PubMed PubMed Citation Articles by Myers, S. T. Related Content Astronomy Special Feature Social Bookmarking What's this? Previous Article | Table of Contents | Next Article Vol. 96, Issue 8, 423 Read More Go to Site The Speed of Light Votes:0 The Speed of Light A Cosmic Speed Limit The velocity of light plays a central role is astronomy and in physics. According to the Einstein's Theory of Relativity, nothing in our universe can exceed the velocity of light; thus, it is a kind of cosmic speed limit against which all other velocities may be measured. More generally, light is part of what is called the electromagnetic spectrum, which includes infrared radiation, radio waves, gamma rays, X-rays, ultraviolet radiation, and so on. All of these are a form of light; they just have energies that differ from the visible light that our eyes can see. Thus, these forms of electromagnetic radiation all travel at the speed of light too. The Speed of Light is Constant Furthermore, contrary to normal intuition, the Theory of Relativity tells u Read More Go to Site Physical Constants and Astronomical Data Votes:0 Physical Constants and Astronomical Data Physical Constants (converted to CGS units from the NIST Constant Index ) Name Symbol Number Exp CGS Units Relative Error (ppm) speed of light in a vacuum c 2.99792458 10 cm s -1 exact Planck constant h 6.6260755(40) -27 erg s 0.60 hbar 1.05457266(63) -27 erg s 0.60 Gravitational constant G 6.67259(85) -8 cm 3 g -1 s -2 128 Electron charge e 4.8032068(14) -10 esu 0.30 Mass of electron m e 9.1093897(54) -28 g 0.59 Mass of proton m p 1.6726231(10) -24 g 0.59 Mass of neutron m n 1.6749286(10) -24 g 0.59 Mass of hydrogen m H 1.6733 -24 g -- Atomic mass unit amu 1.6605402(10) -24 g 0.59 Avagadro's number N A 6.0221367(36) 23 0.59 Boltzmann constant k 1.380658(12) -16 erg k -1 8.5 Electron volt eV 1.6021772(50) -12 erg ~0.60 Radiation density constant a 7 Read More Go to Site Physical Constants and Astronomical Data Votes:0 Physical Constants and Astronomical Data New! Try my Physical Calculator . It is a JavaScript calculator with all of the constants below programmed into it. Physical Constants (converted to CGS units from the NIST Constant Index ) Name Symbol Number Exp CGS Units Relative Error (ppm) speed of light in a vacuum c 2.99792458 10 cm exact Planck constant h 6.6260755(40) -27 erg s 0.60 hbar 1.05457266(63) -27 erg s 0.60 Gravitational constant G 6.67259(85) -8 cm 3 g -1 s -2 128 Electron charge e 4.8032068(14) -10 esu 0.30 Mass of electron m e 9.1093897(54) -28 g 0.59 Mass of proton m p 1.6726231(10) -24 g 0.59 Mass of neutron m n 1.6749286(10) -24 g 0.59 Mass of hydrogen m H 1.6733 -24 g -- Atomic mass unit amu 1.6605402(10) -24 g 0.59 Avagadro's number N A 6.0221367(36) 23 0.59 Boltzmann const Read More Go to Site A RELATION BETWEEN DISTANCE AND RADIAL VELOCITYAMONG EXTRA-GALACTIC NEBULAE by Edwin Hubble Votes:0 From the Proceedings of the National Academy of Sciences Volume 15 : March 15, 1929 : Number 3 A RELATION BETWEEN DISTANCE AND RADIAL VELOCITY AMONG EXTRA-GALACTIC NEBULAE By Edwin Hubble Mount Wilson Observatory, Carnegie Institution of Washington Communicated January 17, 1929 Determinations of the motion of the sun with respect to the extra-galactic nebulae have involved a term of several hundred kilometers which appears to be variable. Explanations of this paradox have been sought in a correlation between apparent radial velocities and distances, but so far the results have not been convincing. The present paper is a re-examination of the question, based on only those nebular distances which are believed to be fairly reliable. Distances of extra-galactic nebulae depend ultimately upon t Read More Go to Site Brief history of c Votes:0 A Brief History of c When the Danish astronomer Olaf Roemer (Philosophical Transactions; June25, 1677) announced to the Paris Academie des Sciences in September 1676that the anomalous behavior of the eclipse times of Jupiter's inner moon,Io, could be accounted for by a finite speed of light, he ran counter tothe current wisdom espoused by Descartes and Cassini. It took another quartercentury for scientific opinion to accept the notion that the speed of lightwas not infinite. Until then, the majority point of view was that the velocityof light was infinite. The Greek philosophers generally followed Aristotle's belief that the speedof light was infinite. However, there were exceptions such as Empedoclesof Acragas (c.450 B.C.) who spoke of light, "traveling or being atany given Read More Go to Site Cosmological Constant Votes:0 Vacuum Energy Density, or How Can Nothing Weigh Something? Recently two different groups have measured the apparent brightness of supernovae with redshifts near z = 1. Based on this data the old idea of a cosmological constant is making a comeback. Einstein Static Cosmology Einstein's original cosmological model was a static, homogeneous model with spherical geometry. The gravitational effect of matter caused an acceleration in this model which Einstein did not want, since at the time the Universe was not known to be expanding. Thus Einstein introduced a cosmological constant into his equations for General Relativity. This term acts to counteract the gravitational pull of matter, and so it has been described as an anti-gravity effect. Why does the cosmological constant behave this way? Thi Read More Go to Site Ebtx - Planck's Constant Votes:0 Planck's Constant P lanck's constant is the cornerstone of existence. It represents the concept of "slop" as applied to the universe as a logical system. For those unfamiliar with the term, mechanical slop is the amount of freeplay in a mechanical device which is engineered into its design to facilitate workability . Example ... If you have a cylindrical sleeve (four inches inside diameter) and a rod (four inch outside diameter) which is to fit into the sleeve ... you have a mechanically impossible situation. You will not be able to insert the rod unless there is some slop gap ... too much and the rod wobbles too little and it doesn't go in . Slop delimits the "action" of the mechanism. If the universe were entirely deterministic (no slop) ... it couldn't go. If it is totally indeterminate Read More Go to Site ESO - 1995 Votes:0 European Organisation for Astronomical Research in the Southern Hemisphere" /> ESO European Organisation for Astronomical Research in the Southern Hemisphere Press Releases 1995 ESO Home User Portal Contact Site Map Search: Go! 23 Nov 2007 ESO for the Public > Press and Media > Press Releases > 1995 jump to navigation jump to content ESO for the Public About ESO ESO at a glance Organigram Director General Governing Bodies Collaborations Contact and Travel ESO Sites Addresses Travel Information Local Information ESO Acronyms ESO Chile Gallery Image Archive View All Top 100 Hall of Fame Zoomable Wallpaper Advanced Search Image Archive Formats Video Archive Press and Media Press Releases 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 Broadcast Services Video News Reels Read More Go to Site exoScience Votes:0 exoScience --> --> CSIRO / Sunday January 31, 1999 Hubble Constant revised yet again An international team led by a young Australian scientist has used CSIRO's Australia Telescope to measure how fast the Universe is expanding?and found it to be both older and larger than previously thought. The expansion is measured as a number called the Hubble Constant. It is used to calculate how big and how old the Universe is. The observing team used a new method that avoids the built-in uncertainties in older methods and found the universe to be 15 billion years old. Astronomers have been wrangling over the value of the Hubble Constant?a number that indicates the expansion rate of the universe and hence its age?for several decades. Measuring it is a key problem that the Hubble Space Telescope was bui Read More Go to Site Fine Structure Constant -- from Eric Weisstein's World of Physics Votes:0 Modern Physics "> Quantum Physics "> Quantum Field Theory "> General Quantum Field Theory Units and Dimensional Analysis "> Dimensionless Parameters Physics Contributors "> Plouffe Fine Structure Constant A dimensionless number that appears in the analysis of quantum electrodynamical Feynman diagrams . It is not currently known if it can be derived from first principals in terms of mathematical constants, but it can be determined as a conglomeration of the electron charge e , ( h-bar ), and the speed of light c . In his later years, the English physicist Arthur Eddington concocted pseudoscientific "proofs" on "physical" grounds that the fine structure constant was exactly 1/136. When experiments yielded a more accurate value, Eddington produced another proof "provi Read More Go to Site Foundations of Electronics - Faraday's Constant Votes:0 Faraday's Constant Using Faraday's constant to solve problems regarding the process of electrolysis. You may find the section on current in the physics tutorial helpful. Redox reactions have many important uses. One of these is electrolysis , the conversion of electrical energy to chemical energy. Do you remember this table? (From the electrodes segment) Anode Oxidation Cathode Reduction In electrolysis, oxidation still occurs at the anode, and reduction still occurs at the cathode, but the polarity of the electrodes is different. Cells Anode Oxidation - Cathode Reduction + Electrolysis Anode Oxidation + Cathode Reduction - Keep this in mind as we go. Faraday's constant is the charge carried by one mole of electrons . There are 6.02214e23 electrons per mole of electrons. (Avogadro's number Read More Go to Site Fundamental Physical Constants Votes:0 Fundamental Physical Constants Data are mainly copied from Fundamental Constants in Physics published by the Chemistry Department of the Free University of Berlin Exponent (base 10) of decimal numbers: e n = 10^ n . Units are separated by spaces, positive numbers denote powers, all units to the right of the slash are in the denominator (negative powers). Planck constant h 6.6260755e-34 J s h/(2 pi) = 1.05457266e-34 J s . Boltzmann constant k_B 1.380658e-23 J/K . Elementary charge e 1.60217733e-19 C . Avogadro number N_A 6.0221367e23 particles/mol Speed of light c 2.99792458e8 m/s Permeability of vacuum mu_0 mu_0 = 4 pi e-7 T2 m3/J 12.566370614e-7 T2 m3/J Permittivity of vacuum epsilon_0 epsilon_0 = 1/ (mu_0 c^2) 8.854187817e-12 C2/J m Fine structure constant 1/alpha 137.0359895 Electron re Read More Go to Site Fundamental Physical Constants Votes:0 Studies Research Groups Talks Safety Chemistry EDP Library Services Miscellaneous print view Fundamental Physical Constants Version of this page using math mode (you need a browser such as Arena !) PostScript Version (without warranty) Planck constant h 6.6260755·10 -34 J·s h / (2 ) = 1.05457266·10 -34 J·s Boltzmann constant k B 1.380658·10 -23 J/K ( = 8.617385·10 -5 eV/K ) Elementary charge e 1.60217733·10 -19 C Avogadro number N A 6.0221367·10 23 particles/mol Speed of light c 2.99792458·10 8 m/s Permeability of vacuum 0 0 = 4 ·10 -7 T 2 ·m 3 /J 12.566370614·10 -7 T 2 ·m 3 /J Permittivity of vacuum 0 0 = 1 / ( 0 c 2 ) 8.854187817·10 -12 C 2 /J·m Fine structure constant 1 / 137.0359895 Electron rest mass m e 9.1093897·10 -31 kg Proton rest mass m p 1.6726231·10 -27 kg Neutron rest mass m Read More Go to Site Fundamental Physical Constants from NIST Votes:0 Information at the foundation of modern science and technology from the Physics Laboratory of NIST CODATA Internationally recommended values of the Constants Topics: Values Energy Equivalents Searchable Bibliography Background Constants Bibliography Constants, Units & Uncertainty home page Latest (2006) values of the constants Version history and disclaimer (e.g., electron mass , most misspellings okay) Search for value by name Display alphabetical list, table (image), or table (pdf) by clicking a category below --> Find the correlation coefficient between any pair of constants Data from the least-squares adjustment of the values of the constants See also Searchable bibliography on the constants Background information related to the constants Links to selected scientific data Chart with se Read More Go to Site Has The Speed Of Light Decayed? Votes:0 Science Frontiers ONLINE No. 58: Jul-Aug 1988 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Has the speed of light decayed? In a recent technical report, The Atomic Constants, Light, and Time , T. Norman and B. Setterfield answer this question affirmatively. Scientific creationists have in the main welcomed this report, because its findings are consistent with their desire to prove the earth very young. However, G.E. Aardsma, at the Institute for Creation Research, in California, urges caution: "Measurements of the speed of light have been made for the past three hundred years which could potentially provide the required empirical basis. Norman and Setterfield tabulate the results of 163 speed of light determ Read More Go to Site http://jpltrs.jpl.nasa.gov/1995/95-1103.pdf Votes:0 PDF Document Read More Go to Site Hubble Constant Votes:0 What's New Site Map NASA Homepage Search: HOME Science Special Exhibit Satellites and Data Teachers' Corner Ask an Astrophysicist Dictionary Resources Feedback Imagine Home | Ask an Astrophysicist | Current page The Question (Submitted October 19, 1997) I've been trying to figure out exactly what the Hubble Constant is for quite a while. I know that it has to do with the expansion rate of the Universe and that it can also directly yield the distance scale and the age of the Universe. Could you possibly explain it to me in fairly simple terms. I'm in 11th grade and I've had about a month's worth of class on astronomy. The Answer Early in this century Edwin Hubble discovered that galaxies are moving rapidly away from us (this was the first evidence for the big bang theory for the creati Read More Go to Site Introduction to Cosmology Web Site Votes:0 MICROWAVE ANISOTROPY PROBE The page you have requested has moved. If you are not directed automatically to the new page (likely, if you are reading this message), use the this link to go there: http://map.gsfc.nasa.gov/m_uni.html Read More Go to Site Physical constants Votes:0 Physical constants 1998 CODATA recommended values Quantity Symbol Value speed of light in vacuum c 299792458 m s -1 (exact) magnetic constant μ 0 4 π ? 10 -7 N A -2 (exact) electric constant 1/μ 0 c 2 ε 0 8.854187817... ? 10 -12 F m -1 (exact) Planck constant h 6.62606876(52) ? 10 -34 J s elementary charge e 1.602176462(63) ? 10 -19 C electron mass m e 9.10938188(72) ? 10 -31 kg 5.485799110(12) ? 10 -4 u proton mass m p 1.67262158(13) ? 10 -27 kg 1.00727646688(13) u neutron mass m n 1.67492716(13) ? 10 -27 kg 1.00866491578(55) u Rydberg constant R ∞ 10973731.568549(83) m -1 Bohr radius a 0 0.5291772083(19) ? 10 -10 m Avogadro constant N A 6.02214199(47) ? 10 23 mol -1 Faraday constant N A e F 96485.3415(39) C mol -1 molar gas constant R 8.314472(15) J K -1 mol -1 Bol Read More Go to Site Physical Constants Do NOT Exist Votes:0 Physical Constants Do NOT Exist Physical Constants Do NOT Exist by Guy Myhre This brief is a nonmathematical description of some of my discoveries, which pertain to the methodology of quantum physics. If, after reading it, you want to delve into detailed mathematical proof of these and other discoveries, please examine my book, Our Unitary Universe . | WritWord Homepage | If They Are Not Physical Constants, What Are They? Most of the physical constants really do NOT exist. This recently discovered fact forever changes the methodology of physics. Yes, they do exist as constants in metric-based equations, but they are not physical constants. For some reason, the physics community has, over the years, elevated the status of these constants by giving them a long, important-sounding name: funda Read More Go to Site Planck's Constant and the Energy of a Photon Votes:0 Planck's Constant and the Energy of a Photon In 1900, Max Planck was working on the problem of how the radiation an object emits is related to its temperature. He came up with a formula that agreed very closely with experimental data, but the formula only made sense if he assumed that the energy of a vibrating molecule was quantized --that is, it could only take on certain values. The energy would have to be proportional to the frequency of vibration, and it seemed to come in little "chunks" of the frequency multiplied by a certain constant. This constant came to be known as Planck's constant , or h , and it has the value This doesn't make any sense to me. I think I'll go ask Dr. Mahan what J means. That's a pretty small constant. Yes, but it was an extremely radical idea to suggest that e Read More Go to Site Scientists Find the True Hubble Constant! Votes:0 Scientists Find the True Hubble Constant! News story originally written on May 26, 1999 Hubble Space Telescope image of spiral galaxy NGC 4603. It is the most distant galaxy with Cepheids used to measure the Hubble Constant. Click on image for full size ( 26K JPG ) Courtesy of NASA After eight long years, the Hubble Space Telescope Key Project Team finally revealed what they believe is the real Hubble Constant. The Hubble Constant is the speed which the Universe is expanding at. For over 70 years, scientists have argued over the exact number. "Before Hubble, astronomers could not decide if the universe was 10 billion or 20 billion years old," said team leader Wendy Freedman of the Observatories of the Carnegie Institution of Washington. "The size scale of the universe had a range so vast t Read More Go to Site Speed of Light Votes:0 The speed of light Light moves with a speed c = 3 x 10 8 m/s. This speed was first measured 1n 1675 by Danish astronomer Olaus Roemer, using observations of the moons of Jupiter . Here is what Roemer saw: He carefully timed the motions of the moons in their orbits. In order to get a consistent picture from the measurements, he needed to account for the time it takes the light to get from Jupiter to Earth, which varies according to how far away Jupiter is away. (But this gives a pretty crude measurement of the speed of light, since the distance to Jupiter was not well known.) ASTR 122 course home page Updated 1 October 2007 Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA Read More Go to Site The Mass of an Electron Votes:0 The Mass of an Electron The mass/charge ratio was measured by J.J. Thomson using a cathode ray tube. The charge of an electron was measured in a famous experiment by Robert Millikan. The mass of an electron was found to be about 2000 times less than the lightest atom (hydrogen). Previous slide Next slide Back to first slide View graphic version Read More Go to Site The Speed of Light - A Limit on Principle? Votes:0 The Speed of Light - A Limit on Principle? This web page has moved to a new address. Please update your links. http://home.sunrise.ch/schatzer/space-time.html Automatically being redirected within a few seconds... (if not, please click on the URL above) Read More Go to Site Theoretical speculations on the Hubble constant Votes:0 Theoretical speculations on the Hubble constant and implications of the CMB observations (giving the same value...) Alain Blanchard 1 and Marian Douspis 1 1 Observatoire astronomique de Strasbourg Introduction A Theoretical Perspective What does the CMB tell us? Likelihood Estimate of the Hubble constant Conclusion How Far Can You Go ? Proceedings of a workshop organized by the Observatoire de Strasbourg La Petite Pierre (Northern Vosges), 25-27 June 1997 Read More Go to Site Untitled Votes:0 M EASURING e U SING THE M ILLIKAN A PPARATUS T OM H AYNIE The charge on the electron is a constant in Physics. This constant was first measured by R.A. Millikan, in 1909-1913, using oil drops. He showed the discreteness of the electron charge as well. Measurement requires balancing the electrical and gravitational forces on the drop. It is possible to use polystyrene spheres which are of uniform radius and density. The mass can be checked from the relationship of the gravitational forces and the viscous forces on a sphere in free fall. The Boltzmann constant can be estimated by the dispersions in the time of the free fall. Theory Apparatus Procedure Results Conclusions Read More Go to Site What is the fine-structure constant? Votes:0 Ask the Experts Physics Job Board University Departments Einstein eGreetings Science eStore Local in California? Visit one of our retail stores. XUMP - Science Toys Question What is the fine-structure constant? Asked by: Joshua Johnson Answer The fine-structure constant is a unitless numerical constant - whose value is approximately equal to: 1/137 . If fact the exact value of the fine-structure constant is: 0.007297351 +/- 0.000000006 . Accepted symbol for the fine-structure constant is Greek alpha ( ). [Ref. 1] What is the physical origin of this constant? Well, it is related to the so called Fine Structure - closely spaced groups of optical spectrum lines of elements like: hydrogen and helium. These optical spectrum lines are in a way the fingerprint of the element's energy levels. Sinc Read More Go to Site [94.02] Measuring Cosmological Parameters with High Redshift Supernovae Votes:0 AAS Meeting #193 - Austin, Texas, January 1999 Session 94. Invited Talks: Perlmutter and Kirshner Invited, Friday, January 8, 1999, 3:40-5:10pm, Ballroom A [Previous] | [Session 94] | [Next] [94.02] Measuring Cosmological Parameters with High Redshift Supernovae R. P. Kirshner (Harvard-Smithsonian CfA) The High-Z Supernova Search Team is an international collaboration formed to measure the deceleration and global geometry of the Universe using Type Ia supernovae. Our group is a collection of more than 20 astronomers from 11 institutions on 4 continents with one goal. Our published work analyzes a sample of 16 high-z supernovae and makes a surprising conclusion. Barring unaccounted-for systematic effects, the Universe appears to be accelerating. Since matter can only slow the expansion, som Read More Go to Site

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