• Radiation fears stalk stellar mission

    Updated: 2010-06-30 10:53:31
    Technical problems could hinder the satellite's ability to map a billion stars in the Milky Way

  • The Postulates of Relativity Refined

    Updated: 2010-06-30 03:02:35
    Summary: motion, increases in direction of motion, and decreases in opposite ... electron is also a wave and that the only thing separating them is ... a particle attains rest mass. ...

  • I still don't get string theory!

    Updated: 2010-06-30 01:57:18
     tring theory still makes no sense to me. If all matter is made of tiny strings of energy, how does that prove the existence of ten dimensions and a zillion new subatomic particles? Someone please explain how this works out.

  • Nd:YVO4

    Updated: 2010-06-29 10:10:56
    Nd:YVO4 is commonly used as an active laser medium for DPSSL. It comes as a transparent blue-tinted material. It is birefringent, therefore rods made of it are usually rectangular.

  • Nd:YAG

    Updated: 2010-06-29 10:10:48
    Nd:YAG is the most widely used active laser medium in solid-state lasers. It can be used in lasers utilizing frequency doubling and frequency tripling, and high-energy Q-switching.

  • KTA crystal

    Updated: 2010-06-29 10:10:35
    KTA is an excellent NLO crystal developed mainly for Optical Parametric Oscillation (OPO)

  • β-BBO

    Updated: 2010-06-29 10:08:23
    β-BBO is a crystal used for frequency mixing and other nonlinear optics applications.

  • Cr:YAG

    Updated: 2010-06-29 10:07:50
    Cr:YAG can be used for passive Q-switching the diode or lamp pumped Nd:YAG, Nd:YLF, Nd:YVO4, Yb:YAG, and other neodymium and yttrium doped lasers at wavelengths between 1000-1200nm.

  • Edward Witten wins Newton medal

    Updated: 2010-06-29 10:07:45
    String theorist honoured for transforming physics

  • Cobolt RumbaTM: Ultra-low noise 1064 nm

    Updated: 2010-06-29 10:07:44
    Cobolt AB announces the release of a new wavelength on the ground breaking single-frequency 05-01 platform released in 2009.

  • Lorentz factor in rotating black holes

    Updated: 2010-06-29 02:20:16
    Summary: does anyone know how much exactly time is dilated and space contracted ... in rotating black holes, by using the Kerr or Kerr-Newman metrics? ...

  • International Conference on Swarm, Evolutionary and Memetic Computing (SEMCCO 2010)

    Updated: 2010-06-29 00:00:00
    Conference: 16 Dec 2010 - 18 Dec 2010, Chennai, India. Organized by SRM University (Chennai), Springer.

  • NEW DRAFT "THEORIES REDUCING TO QUANTUM MECHANICS, QUANTUM ELECTRODYNAMICS DOESNT"

    Updated: 2010-06-28 22:48:18
    Summary: NEW DRAFT "THEORIES REDUCING TO QUANTUM MECHANICS, ... The theories considered are: relativistic quantum electrodynamics - ...

  • The simplist thing in physics is to explain the Big Bang

    Updated: 2010-06-28 07:51:54
    sci.physics.relativity: The simplist thing in physics is to explain the Big Bang

  • Researching Quanitifying Gravity.

    Updated: 2010-06-28 01:53:38
    Summary: of constructing a stress energy tensor ... of both theories (but of course, these days physicists decree that ... Vanstone is strongly dedicated to GR and Unified Field Theory, ...

  • Summer School

    Updated: 2010-06-26 18:00:58
    This is the time of the year when young particle physicists usually want to go to school, more precisely, a “summer school” held in some pleasant location. These typically have a series of survey lectures on the hot topics of the subject, aimed at the level of advanced graduate students and postdocs. These days, the [...]

  • Availables : More that 3500 Solutions manuals and Test Banks (Part 2)

    Updated: 2010-06-26 07:41:05
    Summary: Math, Statistics & Probability ... Advanced Engineering Mathematics ... Paul Calter & Michael Calter) ...

  • GR prediction for precession of perihelion of Mercury is not quite right

    Updated: 2010-06-25 21:25:47
    Summary: Amount: arcsec/Julian century ... The discrepancy is larger than the observational error ... In addition GR predicts that even a circular orbit with an ...

  • Preferred Frame Theory indistinguishable from SR

    Updated: 2010-06-25 16:14:55
    Summary: accept the relativity principle. ... There is a preferred frame, F, and there is an associated ... coordinate system. ... found in SR, namely, mutual time dilation, is not present in these ...

  • Centre of mass inertial framesy are the unique ones in 1905 Relativity

    Updated: 2010-06-25 15:00:58
    Summary: Let be any body set with a material point modelling each one. ... want to describe the movements of the bodies in an inertial frame, ... bodies themselves to determine inertial frames. ...

  • Relativity Error

    Updated: 2010-06-25 04:08:34
    Summary: viewed in the stationary system, are synchronous; ... arrival at B the two clocks no longer synchronize, ... Einstien, Electrodynamics of Moving Bodies ...

  • CMS Exotica hotline leads hunt for exotic particles

    Updated: 2010-06-24 19:59:37
    Strangers in the dark: they meet, make contact, and break away with force, careless of what they leave behind. At midnight each night, snapshots of these frenzied chance encounters are collected for curious eyes. In the morning, those onlookers reconstruct the story that each image tells, tracing the mysterious paths born from a fateful meeting. This [...]

  • Could Dark Matter be the Dirac Sea?

    Updated: 2010-06-24 04:02:14
    sci.physics.relativity: Could Dark Matter be the Dirac Sea?

  • The Answer to Pauli, gravity & force of charge

    Updated: 2010-06-22 15:08:40
    Summary: These forces of charge form waves in time, ... peaks represent repulsive forces thus unlike photon waves, ... If one was shrunken to measure the charge and wave at say 1 arc second ... when two identical atoms approach they most likely behave ...

  • Atomic clock behaviour in a gravitational field explained with 1905 Relativity

    Updated: 2010-06-22 14:43:45
    Summary: Let be two material points M and m (one with a great mass M, ... where K is the Kinetic Energy and U the Potential Energy. ... If the body is at rest, K=0, being then U measured by the rest mass. ... Its limit maximal value when r tends to infinite is ...

  • Perpetual motion vs. human motion

    Updated: 2010-06-22 03:43:00
    sci.physics.relativity: Perpetual motion vs. human motion

  • String Theory Fan

    Updated: 2010-06-22 03:05:41
    One of the weirder battles of the String Theory wars became known to some as “trackbackgate”, referring to arguments over the arXiv’s policy of not allowing trackbacks to this blog. I’ve mercifully forgotten the details of the story, other than that I wasted a lot of time arguing the issue with the authorities at the [...]

  • Mathematical Proof that Relativity Might be Wrong !

    Updated: 2010-06-21 23:39:45
    Summary: a twin take one of the particle tweezed into ... travel and come back 10 minutes younger ... the cat cannot be both dead and (both dead and ...

  • Lying for Einstein

    Updated: 2010-06-21 20:58:14
    Summary: younger than the other, which is absurd. ... Do you want me to post proof that you are a liar, ...

  • Potential Energy in 1905 Relativity

    Updated: 2010-06-21 14:51:17
    Summary: energy relationship from the Conservation Principle of Energy, ... expression is the Conservation Principle of Energy ... Does any reader know in the 1905 context any other kind of energy E ...

  • Why does every dork and his dog continue to call it contraction?

    Updated: 2010-06-21 14:34:06
    Summary: younger than the other, which is absurd. ... An ideal clock traveling at speed v for time period t will show ... An extended object traveling at speed v will, ... = less seconds for the moving clock. ...

  • Relativity and Quantum Theory

    Updated: 2010-06-21 06:19:33
    Summary: The basic assumption is a doppler effect of quantum mechanic wave functions. ... If anybody is interested in the mathematical equations you can find them ...

  • colp, why did AE use the word "relativity"?

    Updated: 2010-06-20 08:57:31
    Summary: younger than the other, which is absurd. ... moving; you say you are stationary and I am moving. ... Consider now the first phase of the symmetric twin puzzle: ... effect, and Einstein was right. ...

  • Relativity into a Win-Win Situation forbidden by Laws of Natire

    Updated: 2010-06-19 01:14:39
    Summary: which is a win-win situation ... forbidden by the laws of nature ... if you see 3 newtons is because the ...

  • Relativity into a Win-Win Situation forbidden by the Laws of Nature !!!

    Updated: 2010-06-19 01:11:17
    Summary: which is a win-win situation ... forbidden by the laws of nature ... if you see 3 newtons is because the ...

  • Aether Displacement - The state of the aether is determined by its connections with the matter

    Updated: 2010-06-17 05:10:46
    Summary: The C-60 molecule is always detected exiting a single ... removed from the exits to the slits. ... easily understood in the theory of Aether Displacement. ...

  • The evidences for the Big Bang

    Updated: 2010-06-16 10:52:29
    THE MAGAZINE Current issue Next issue Back issues Special issues Meet the staff Magazine history Contributor guidelines Sweepstakes Trips and tours For the media Contact Us Our products See inside Advertise with Us WELCOME TO ASTRONOMY StarDome Astronomy for kids Intro to the sky Astronomy Myths Urban skies Equipment Product showcase Glossary Sky Events Constellation Observing COLUMNISTS Bob Berman David H . Levy Stephen . J O'Meara Glenn Chaple Phil Harrington SUBSCRIBER EXTRAS StarDome PLUS Star Atlas Bob Berman’s strange universe David H . Levy's evening stars Glenn Chaple’s observing basics Phil Harrington's binocular universe Stephen James O'Meara's secret sky The sky this month Ask Astro Annual index Multimedia gallery Web extras Equipment Review Archive COMMUNITY News E-mail

  • Quick note: Two proposals in breaking of the equivalence principle

    Updated: 2010-06-16 03:25:00
    : : DiY quantum gravity An independent viewpoint about quantum . gravity Wednesday , June 16, 2010 Quick note : Two proposals in breaking of the equivalence principle Until Friday it is very unlikely that I have time to properly read the two articles that I am going to link here . But I find that they are challenging enough to leve a note abut . them The first article was cited yesterday in the arxiv blog : New Quantum Theory Separates Gravitational and Inertial Mass if you are Spanish and prefer reading it in that language there is a translated version by kanijo : Nueva teoría cuántica separa las masas gravitatoria e inercial Those entries make reference to the following arxiv paper : Inertial And Gravitational Mass In Quantum Mechanics I haven't read the actual paper , as I said I have

  • New theory of gravity

    Updated: 2010-06-15 22:26:44
    Summary: I propose a new theory of gravity. ... the two objects only appear to land at the ... same time because, in reference to the size of the Earth, the two ... different weighted objects are virtually the same weight when compared ...

  • Three nerds walk into a bar…

    Updated: 2010-06-15 15:46:18
    Forty-odd Chicagoans gathered in a bar on June 3, not to watch the Blackhawks in the Stanley Cup finals, but to hear Jason St. John talk about particle colliders, the Standard Model and how the Large Hadron Collider won’t be the end of us all. His lecture was part of Chicago’s inaugural Nerd Nite, a monthly series of informal talks intended to educate and entertain the community’s “lay nerds,” as St. John describes them, while they kick back with beers and martinis.

  • Expansion Of The Universe According To Homogeneity

    Updated: 2010-06-15 09:25:26
    THE MAGAZINE Current issue Next issue Back issues Special issues Meet the staff Magazine history Contributor guidelines Sweepstakes Trips and tours For the media Contact Us Our products See inside Advertise with Us WELCOME TO ASTRONOMY StarDome Astronomy for kids Intro to the sky Astronomy Myths Urban skies Equipment Product showcase Glossary Sky Events Constellation Observing COLUMNISTS Bob Berman David H . Levy Stephen . J O'Meara Glenn Chaple Phil Harrington SUBSCRIBER EXTRAS StarDome PLUS Star Atlas Bob Berman’s strange universe David H . Levy's evening stars Glenn Chaple’s observing basics Phil Harrington's binocular universe Stephen James O'Meara's secret sky The sky this month Ask Astro Annual index Multimedia gallery Web extras Equipment Review Archive COMMUNITY News E-mail

  • Predictions From David Gross

    Updated: 2010-06-14 23:47:28
    Video of David Gross’s talk at the Physics at the LHC 2010 conference is now available. He devotes much of the talk to reviewing predictions he made back in 1993 of what would happen by 2008, and making new predictions for what will happen by 2020. The 1993 experimental predictions that didn’t work out could [...]

  • Rewriting textbooks and remeasuring the particle data booklet at the LHC

    Updated: 2010-06-14 12:07:54
    During last week's Physics at LHC conference, textbooks were being literally rewritten as experimental particle physicists presented their remeasurements of the data contained in the particle data booklet, which contains all possible data for all existing and hypothetical particles. One theorist presented his prediction for a page from the 2016 version of the booklet.

  • equivalence

    Updated: 2010-06-14 10:36:11
    Summary: Einstein declaring that a uniform gravitational field is equivalent to ... to meet all objects, This is the weak equivalence principle, and it is ... And then you read that General Relativity governs the ...

  • Energy in Space

    Updated: 2010-06-11 19:34:54
    If indeed every region of space contains a non zero amount of energy then energy is being added to the universe as it expands, but since matter is being spread more thinly the actual energy per unit volume goes down. I wonder if the universe were ever to contract back to a singularity would the energy added by the expansion be destroyed in the process or go into the singularity? Along that line of though, I wonder if the universe contained nothing but a very large black hole, would the black hole be able suck up all the space in the universe outside itself?

  • Drinking data from a fire hose at the LHC

    Updated: 2010-06-11 19:21:15
    The Large Hadron Collider's beam brightness has steadily increased over the past two and a half months. It currently takes a minute to see as many collisions as we used to see in a day. Very soon, the same number of collisions will take seconds.

  • LHC Update

    Updated: 2010-06-11 12:49:39
    See here for a new status report on the state of beam commissioning at the LHC. About two weeks ago a peak luminosity of about 2 x 1029cm-2s-1 was reached, using beams with 13 bunches, but each bunch relatively low intensity. Since that time, efforts have been directed at increasing the bunch intensity towards nominal [...]

  • Scientists present first “bread-and-butter” results from LHC collisions

    Updated: 2010-06-08 14:50:03
    It's been just over two months since the first high-energy proton collisions took place in the Large Hadron Collider, and scientists from the LHC experiments have been working feverishly to analyze the data now pouring from their detectors. The results of the first analyses using real LHC data are being presented this week at the "Physics at LHC" conference at the DESY laboratory in Hamburg, Germany.

  • In Arxiv today: Supersymmetry breaking

    Updated: 2010-06-07 08:48:00
    : : DiY quantum gravity An independent viewpoint about quantum . gravity Monday , June 07, 2010 In Arxiv today : Supersymmetry breaking Today there are some interesting papers in arxiv , although not so many as the previous Monday . Some of them are purely mathematical , or concern formal aspects . I like formal aspects , and mathematics , but because I had some leaks on recent phenomenology I am provisionally interested in more mundane topics . One key aspect in phenomenology is supersymmetry breaking . To begin with the MSSM minimal supersymmetricla standard model only can get supersymmetry breaking by means of soft terms which are outside the model itself . These terms must arise by some method that generates . them The older studied method is gravity mediates supersymmetry breaking .

  • Testing beeeeeep

    Updated: 2010-06-04 21:54:39
    This is a test of the emergency blog system. If you are reading this, remain calm. There is no emergency at this point in time. In the event of an emergency, the emergency blog system will be...

  • Could DZero result point to multiple Higgses?

    Updated: 2010-06-04 21:53:15
    Theorists say the discovery of a significant imbalance between the production of matter and antimatter during particle collisions at the Tevatron points to new physics at work -- including the possibility that there may be five types of Higgs boson, rather than just one.

  • civil vs mechanical

    Updated: 2010-06-04 03:46:08
    i wish to pursue my career in engineering field.i am confused over mechanical and civil engineering.which would be better?

  • basic methods

    Updated: 2010-06-03 01:39:05
    Back in High School I learned the following If you have to equations on the form

  • Heterotic phenomenology

    Updated: 2010-06-01 07:34:00
    : DiY quantum gravity An independent viewpoint about quantum . gravity Tuesday , June 01, 2010 Heterotic phenomenology I have talked quite often in this blog about F-theory . This is partially due to historical reasons , that is , the F-theory GUT revolution happened recently , while this blog growth . Also the influence of a friend of mine to let learn algebraic geometry was a plus because F-theory relies a lot in that area of . maths Of course another reason is that they are very good developed . framework But that doesn't mean that there is not development in other areas of string theory . In particular from the eighties heterotic strings where the best candidate for a phenomenological model . Even today most books in string theory such as the Becker- Becker-Swhartz one use the

  • Length Contraction - Time Dilation

    Updated: 2010-05-30 15:56:51
    Derivation for length contraction and time dilation formulas for arbitrary transformations between inertial frames.

  • General Euler-Lagrange derivation for proper and coordinate acceleration

    Updated: 2010-05-28 14:36:39
    Use Euler-Lagrange formalism to determine the proper and coordinate acceleration for a gravitational field

  • Equivalence Principe: Time Dilation

    Updated: 2010-05-27 01:45:23
    Equivalence principle , time dilation due to relative accelerated motion vs. time dilation due to gravitational field gradient.

  • random

    Updated: 2010-05-21 01:19:10
    how do I post a thred?

  • Big chill or big crunch

    Updated: 2010-05-19 17:21:10
    THE MAGAZINE Current issue Next issue Back issues Special issues Meet the staff Magazine history Contributor guidelines Sweepstakes Trips and tours For the media Contact Us Our products See inside Advertise with Us WELCOME TO ASTRONOMY StarDome Astronomy for kids Intro to the sky Astronomy Myths Urban skies Equipment Product showcase Glossary Sky Events Constellation Observing COLUMNISTS Bob Berman David H . Levy Stephen . J O'Meara Glenn Chaple Phil Harrington SUBSCRIBER EXTRAS StarDome PLUS Star Atlas Bob Berman’s strange universe David H . Levy's evening stars Glenn Chaple’s observing basics Phil Harrington's binocular universe Stephen James O'Meara's secret sky The sky this month Ask Astro Annual index Multimedia gallery Web extras Equipment Review Archive COMMUNITY News E-mail

  • Hello!

    Updated: 2010-05-17 18:46:38
    Hey. I'm not quite sure what to say. I'm new to PF, and thought I'd introduce myself. I'm 17 and I live in Ireland. Next month I'm starting the supposed Irish equivelent of the A-Level and the...

  • Simplify General Relativity?

    Updated: 2010-05-16 08:11:43
    *A Personal Note* I completed my Master’s degree in Physics back in May of 1999. I’ve been somewhat obsessed with learning and understanding relativity since I was a teenager and this represented...

  • Could it be Pati-Salam, at the end?

    Updated: 2010-05-15 00:43:00
    Both U(1)xSU(3)xSU(2)xSU(2) and the full SU(4)xSU(2)xSU(2) live in 8 extra dimensions, as F-theory lives, and they probably need one of the extra dimensions to be infinitesimal, because U(1) B-L...

  • The Pioneer Anomoly

    Updated: 2010-05-13 16:46:43
    THE MAGAZINE Current issue Next issue Back issues Special issues Meet the staff Magazine history Contributor guidelines Sweepstakes Trips and tours For the media Contact Us Our products See inside Advertise with Us WELCOME TO ASTRONOMY StarDome Astronomy for kids Intro to the sky Astronomy Myths Urban skies Equipment Product showcase Glossary Sky Events Constellation Observing COLUMNISTS Bob Berman David H . Levy Stephen . J O'Meara Glenn Chaple Phil Harrington SUBSCRIBER EXTRAS StarDome PLUS Star Atlas Bob Berman’s strange universe David H . Levy's evening stars Glenn Chaple’s observing basics Phil Harrington's binocular universe Stephen James O'Meara's secret sky The sky this month Ask Astro Annual index Multimedia gallery Web extras Equipment Review Archive COMMUNITY News E-mail

  • Well when life hands you lemons.

    Updated: 2010-05-11 01:28:19
    I know everything there is to know in the universe...ask me anything.

  • Uber-naturalness

    Updated: 2010-05-10 08:13:00
    : DiY quantum gravity An independent viewpoint about quantum . gravity Monday , May 10, 2010 Uber-naturalness The most interesting paper today n arxiv hep_th is very probably this : Uber-naturalness : unexpectedly light scalars from supersymmetric extra dimensions This is the : abstract Standard lore asserts that quantum effects generically forbid the occurrence of light non-pseudo-Goldstone scalars having masses smaller than the Kaluza Klein scale , M_KK , in extra-dimensional models , or the gravitino mass , M_3 2, in supersymmetric situations . We argue that a hidden assumption underlies this lore : that the scale of gravitational physics , M_g , e.g . the string scale , M_s , in string theory is of order the Planck mass , M_p 10^18 GeV . We explore sensitivity to this assumption using

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