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Topic: Gravitational radiation

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  Gravitational radiation Summary
Like electromagnetic radiation, gravitational radiation is believed to travel at the speed of light, however while electromagnetic waves are 'spin-1' (meaning their direction of oscillation is perpendicular to their direction of propagation) gravitational waves are 'spin-2'.
The strongest gravitational waves we can expect to observe on Earth would be generated by very distant and ancient events in which a great deal of energy moved very violently (examples include the collision of two neutron stars, or the collision of two super massive fl holes).
A sufficiently strong sea of primordial gravitational radiation, with an energy density exceeding that of the big bang electromagnetic radiation by a few orders of magnitude, would shorten the life of the universe, violating existing data that show it is at least 13 billion years old.
www.bookrags.com /Gravitational_radiation   (4565 words)

 Sources of Gravitational Waves - Gravitational Waves   (Site not responding. Last check: 2007-10-20)
A time-varying gravitational dipole is found to be impossible due to a violation of the law of conservation of angular momentum.
The gravitational waves created by “everyday” matter moving with a time-varying quadrupole moment are so extraordinarily small that they are not worth considering; the waves only become significant in systems that move at near-relativistic speeds (at significant fractions of the speed of light) and are very massive.
Gravitational waves are emitted in the direction perpendicular to the plane of rotation; this is a consequence of the aforementioned quadrupolar nature of gravitational radiation emission, and is discussed in more detail in the general relativity section.
web.syr.edu /~dmalling/sources.html   (944 words)

 More on Gravitational Radiation
In physics, gravitational radiation is energy that is transmitted through waves in the gravitational field of space-time, according to Albert Einstein's theory of general relativity: The Einstein field equations imply that any accelerated mass radiates energy this way, in the same way as the Maxwell equations that any accelerated charge radiates electromagnetic energy.
Gravitational radiation is the overall result of gravitational waves in bulk and refers to the concept for the phenomenon known as gravity.
A sufficiently strong sea of primordial gravitational radiation (energy density exceeding that of the big bang electromagnetic radiation by a few orders of magnitude) would shorten the life of the universe, violating existing data that show it is at least 13 billion years old.
www.artilifes.com /gravitational-radiation.htm   (1146 words)

 black-holes.org—Sources of Gravitational Radiation
Gravitational waves, like the ones shown distorting the boat on the last page, pass through the Earth constantly.
One reason that the effects of gravitational waves are so small is that they get smaller the farther we are from their source.
In just the same way, gravitational waves spread out when we are far away from them, and their amplitude goes down.
www.black-holes.org /gwa2.html   (334 words)

 6 Prospects of Gravitational Radiation   (Site not responding. Last check: 2007-10-20)
Although the strength of the gravitational radiation varies with the orientation of the binary, an angle-averaged estimate of the signal strength is [2
By focusing the search for gravitational radiation using known positions of suspected sources, it is possible to increase the signal-to-noise ratio for the detected signal.
White dwarf-neutron star binaries that are expected to be progenitors of the millisecond pulsars must pass through a phase of gravitational radiation after the degenerate core of the donor star emerges from the common envelope phase and before the spin-up phase begins with the onset of mass transfer from the WD to the neutron star.
www.univie.ac.at /EMIS/journals/LRG/Articles/lrr-2002-2/articlese6.html   (767 words)

 Gravitational radiation in the Einstein, Brans-Dicke and Rosen bi-metric theories
In the EIH method, radiation is inferred to the order of recursion to which the theorist is willing or capable of going, with exact results possible in principle in the limit.
The general theory of relativity predicts radiation that, in the lowest order, is proportional to the third derivative of the quadrupole moment of the mass-energy distribution.
Here we develop expressions for quadrupole gravitational radiation in the Brans-Dicke theory using the weak field technique and apply these results, which are applicable in general, to the specific example of PSR 1913+16, though its orbit is eccentric.
www.davis-inc.com /relativity   (1623 words)

 Radiation - Wikipedia, the free encyclopedia
Radiation in physics is the process of emitting energy in the form of waves or particles.
Various types of radiation may be distinguished, depending on the properties of the emitted energy/matter, the type of the emission source, properties and purposes of the emission, etc. When used by the general public, the word "radiation" commonly refers to ionizing radiation.
Alpha radiation, composed of the nuclei of helium-4 atoms.
en.wikipedia.org /wiki/Radiation   (180 words)

 ESA Science & Technology: Gravitational Waves
It was not until the late 1950s that some relativity theorists, H. Bondi in particular, rigorously proved that gravitational radiation was in fact a physically observable phenomenon, that gravitational waves carry energy, and that as a result a system that emits gravitational waves should lose energy.
This is why the lowest order asymmetry producing electromagnetic radiation is the dipole moment of the charge distribution, whereas for gravitational waves it is a change in the quadrupole moment of the mass distribution.
A gravitational wave passing through the Solar System creates a time-varying strain in space that periodically changes the distances between all bodies in the Solar System in a direction that is perpendicular to the direction of wave propagation.
sci.esa.int /science-e/www/object/index.cfm?fobjectid=31417   (774 words)

 01.07.2002 - UC Berkeley astronomers set new limits on gravitational wave background
The longer time base makes the UC Berkeley analysis sensitive to gravitational waves with longer periods, which, in turn, leads to a reduction in the upper limit of energy density in the gravitational wave background radiation by a factor of 10.
The gravitational waves the team is looking for come from massive fl holes orbiting one another, the expected result of the merger of two galaxies with fl holes at the center.
Gravitational waves propagate as a ripple in the fundamental structure of space-time.
www.berkeley.edu /news/media/releases/2002/01/07_array.html   (1047 words)

 Einstein's GWs May Set Speed Limit For Pulsar Spin - July 2, 2003
Material flowing onto the pulsar surface from its companion star tends to quicken the spin, but loss of energy released as gravitational radiation tends to slow the spin due to the principle of conservation of energy.
Gravitational radiation, ripples in the fabric of space predicted by Albert Einstein, may serve as a cosmic traffic enforcer, protecting reckless pulsars from spinning too fast and blowing apart, according to a report published in the July 3 issue of Nature.
Gravitational waves, analogous to waves upon an ocean, are ripples in four-dimensional spacetime.
www.ligo.caltech.edu /LIGO_web/gsfc   (1157 words)

 Gravitational Radiation
Gravitational waves have a polarization pattern that causes objects to expand in one direction, while contracting in the perpendicular direction.
All oscillating radiation fields can be quantized, and in the case of gravity, the intermediate boson is called the "graviton" in analogy with the photon.
A definitive test would be produced by LIGO in coincidence with optical measurements of some catastrophic event which generates enough gravitational radiation to be detected.
math.ucr.edu /home/baez/physics/Relativity/GR/grav_radiation.html   (738 words)

 Scientific center of gravitational-wave research "DULKYN"
The laser generation frequency shift at changing the gravitational field strength is cooperative effect, conditioned, on the one hand, by translation of the basic frequency of active medium individual atom radiation, and, on the other hand, by the resonator eigenfrequences translations at the cost of resonator optical path variation.
The detector is designed for detection of periodic low-frequency (in the range from dozens of Hertz to milliHertz) gravitational radiation from relativistic binary or single pulsars with accurately predictable data on the rotation frequency, angular coordinates, distance to the source, gravitational radiation amplitude and the orbital plane angle.
As for the natural fluctuations conditioned by spontaneous radiation of the atoms of active medium they are found to be minimal, if one works in the synchronization band, when the generation in the reference and the signal resonators occurs at the same frequency.
dulkyn.org.ru /concept.html   (2222 words)

 Advanced State
But since the gravitational force between the electrons is only about 10 to the power of -42 times as strong as the electric force, the resulting gravitational waves carry only 10 to the power of -42 times as much energy as the electromagnetic waves.
Because gravitational waves are ripples in the geometry of space, the cylinder should vibrate slightly when a gravitational wave passes through it.
When LIGO becomes fully operational after the year 2000, it should be able to detect bursts of gravitational waves from colliding neutron stars or the collapsing cores of supernovae as far away as 2 x 10 to the power of 7 parsecs (about 7 x 10 to the power of 7 light years).
library.thinkquest.org /C0116043/advancedstate.htm   (3799 words)

 Gravitational Waves   (Site not responding. Last check: 2007-10-20)
Superficially, there are many similarities between gravity and electricity; for example, Newton's law for the gravitational force between two point masses and Coulomb's law for the electric force between two point charges both vary as the inverse square of the separation distance.
However, because the coupling of gravitational forces to masses is intrinsically much weaker than the coupling of electromagnetic forces to charges, the generation and detection of gravitational radiation are much more difficult than those of electromagnetic radiation.
According to Einstein's theory of general relativity, such a system ought to be losing orbital energy through the radiation of gravitational waves at a rate that would cause them to spiral together on a time scale of about 3 10 years.
abyss.uoregon.edu /~js/glossary/gravitational_waves.html   (432 words)

 PhysOrgForum Science, Physics and Technology Discussion Forums -> electromagnetic and gravitational radiation
Gravity does "radiate" from objects and this can cause indirect losses by creating EMF radiation for example, but what they haven't detected are gravitational waves.
For example, during this experiment the gravity is radiated from the rotating system of spheres and the energy is transferred to the piezodetector at the distance (even behind the aluminium cover of the stator block).
Gravitation is a non propagating force, gravitational radiation is radiating only in the mind and not into the space
forum.physorg.com /index.php?showtopic=5145   (1873 words)

 Force Interactions
Radiation flowing through space might erroneously be "called" the fabric of space; and radiation is known to be subject to diversion or warping.
The prime background radiation of this model may be called a fabric, space-time or an implicate order and be subject to warping, focusing and shadowing, but the Cartesian coordinates of free space remain straight line, un-warped and do not consist of a fabric or other geometry.
For gravitational force without relative motion, as on the surface of a planet, the unbalanced flow is a steady state interaction with constant wavelength photons.
home.netcom.com /~sbyers11/ForceInteract.htm   (11383 words)

 Gravity and Inertia via Radiation Pressure
A surface gravity and/or radiation pressure limit are shown to exist when the radiation flow is totally shielded by large planets.
A multitude of combinations of the electrostatic, magnetic and inertial forces may be tried, with the objective of shielding or focusing the radiation to modify the local effects of gravity and inertia upon an object.
The medium (aether) of this radiation and shadowing model is the Prime non electromagnetic non particulate radiation that pervades all space and matter.
pw1.netcom.com /~sbyers11/index.html   (846 words)

 ScienceDaily: Einstein's Gravitational Waves May Set Speed Limit For Pulsar Spin
Science Daily — Gravitational radiation, ripples in the fabric of space predicted by Albert Einstein, may serve as a cosmic traffic enforcer, protecting reckless pulsars from spinning too fast and blowing apart, according to a report published in the July 3 issue of Nature.
Gravitational wave -- In physics, in terms of a metric theory of gravitation, a gravitational wave is a fluctuation in the curvature of space-time which propagates as a wave, traveling outward from a moving object or...
Gravitation -- Gravity is a force of attraction that acts between bodies that have mass.
www.sciencedaily.com /releases/2003/07/030707091139.htm   (2080 words)

 Gravitational wave - Wikipedia, the free encyclopedia
In physics, a gravitational wave is a fluctuation in the curvature of spacetime which propagates as a wave, traveling outward from a moving object or system of objects.
The simplest example of a strong source of gravitational waves is a spinning neutron star with a small mountain on its surface.
In general terms, gravitational waves are radiated by objects whose motion involves acceleration, provided that the motion is not perfectly spherically symmetric (like a spinning, expanding or contracting sphere) or cylindrically symmetric (like a spinning disk).
en.wikipedia.org /wiki/Gravitational_radiation   (4570 words)

 gravitational radiation
- "gravitation radiation" (the subject of this thread) has been "observed" in at least one binary pulsar (a pair of closely orbiting neutron stars), in the sense that the orbits appear to be changing in a way which implies a loss of energy in the system.
The energy loss is hypothesised to be gravitational radiation, and the observed and predicted changes in the pulsar's orbit are consistent with GR.
The gravitational radiation from binary pulsars - at least, those we've found to date - is too weak to be detected by LIGO.
www.physicsforums.com /showthread.php?p=86369   (937 words)

 6.3 Gravitational radiation back-reaction
The key differences are that here gravitational radiation itself is the detected signal, rather than radio pulses, and the phase evolution alone carries all the information.
The analysis of gravitational wave data from such sources will involve some form of matched filtering of the noisy detector output against an ensemble of theoretical ``template'' waveforms which depend on the intrinsic parameters of the inspiralling binary, such as the component masses, spins, and so on, and on its inspiral evolution.
According to GR, this spacetime must be the Kerr spacetime of a rotating fl hole, uniquely specified by its mass and angular momentum, and consequently, observation of the waves could test this fundamental hypothesis of GR [114, 107].
relativity.livingreviews.org /Articles/lrr-2001-4/node28.html   (1016 words)

 A Study of the Retarded Gravitational Field
In the case of two equal masses in a mutual circular orbit these solutions predict a radiated power that is 1/3 of the value given by the general theory.
The gravitational wave has not yet been directly detected, but the observations of the pulsar binaries are now accurate enough that the orbital decay due to gravitational radiation can be measured [6].
In that frame of reference, and in the weak field limit, the gravitational 4-potential along the future light cone is equivalent to the simple inverse square law relationship of the Newton theory if the particle is moving at a constant velocity.
www.s-4.com /retard   (1024 words)

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