Gravity waves analysis opens 'completely new sense'

spaceref.com ^ | 29 Oct 02 | Washington Univ

[RightWhale]

Gravity waves analysis opens 'completely new sense'

PRESS RELEASE

Washington University in St. Louis

St. Louis, MO. -- Sometime within the next two years, researchers will detect the first signals of gravity waves -- those weak blips from the far edges of the universe passing through our bodies every second. Predicted by Einstein's theory of general relativity, gravity waves are expected to reveal, ultimately, previously unattainable mysteries of the universe.

Wai-Mo Suen, Ph.D., professor of physics at Washington University in St. Louis is collaborating with researchers nationwide to develop waveform templates to comprehend the signals to be analyzed. In this manner, researchers will be able to determine what the data represent -- a neutron star collapsing, for instance, or black holes colliding.

"In the past, whenever we expanded our band width to a different wavelength region of electromagnetic waves, we found a very different universe," said Suen. "But now we have a completely new kind of wave. It's like we have been used to experiencing the world with our eyes and ears and now we are opening up a completely new sense."

Suen discussed the observational and theoretical efforts behind this new branch of astronomy at the 40th annual New Horizons in Science Briefing, Oct. 27, 2002, at Washington University in St. Louis. The gathering of national and international science writers is a function of the Council for the Advancement of Science Writing.

Gravity waves will provide information about our universe that is either difficult or impossible to obtain by traditional means. Our present understanding of the cosmos is based on the observations of electromagnetic radiation, emitted by individual electrons, atoms, or molecules, and are easily absorbed, scattered, and dispersed. Gravitational waves are produced by the coherent bulk motion of matter, traveling nearly unscathed through space and time, and carrying the information of the strong field space-time regions where they were originally generated, be it the birth of a black hole or the universe as a whole.

This new branch of astronomy was born this year. The Laser Interferometer Gravitational Wave Observatory (LIGO) at Livingston, Louisiana, was on air for the first time last March. LIGO, together with its European counterparts, VIRGO and GEO600, and the outer-space gravitational wave observatories, LISA and LAGOS, will open in the next few years a completely new window to the universe.

Supercomputer runs Einstein equation to get templates

Suen and his collaborators are using supercomputing power from the National Center for Supercomputing Applications at the University of Illinois, Urbana-Champaign, to do numerical simulations of Einstein's equations to simulate what happens when, say, a neutron star plunges into a black hole. From these simulations, they get waveform templates. The templates can be superimposed on actual gravity wave signals to see if the signal has coincidences with the waveform.

"When we get a signal, we want to know what is generating that signal," Suen explained. "To determine that, we do a numerical simulation of a system, perhaps a neutron star collapsing, in a certain configuration, get the waveform and compare it to what we observe. If it's not a match, we change the configuration a little bit, do the comparison again and repeat the process until we can identify which configuration is responsible for the signal that we observe."

Suen said that intrigue about gravity waves is sky-high in the astronomy community.

"Think of it: Gravity waves come to us from the edge of the universe, from the beginning of time, unchanged," he said. "They carry completely different information than electromagnetic waves. Perhaps the most exciting thing about them is that we may well not know what it is we're going to observe. We think black holes, for sure. But who knows what else we might find?"

[Physicist]

I'd really like to see where the Lorentz contraction was measured. If it can be measured, one can go back and properly redo Michelson-Morley and measure the anisotropy of c.

Michelson-Morely is how we can measure Lorentz contraction. Three things have to come into play to produce a null result in that experiment: the finite speed of light, time dilation, and Lorentz contraction. Now that we can independently measure the first two to a high degree of accuracy, we can take the MM experiment as a test of Lorentz contraction. As predicted by relativity, it is exactly as much as it needs to be to cancel the influence of the first two effects on the interferometer.

[Physicist]

Take two lead spheres, each on the end of a single rod. Rotate radially about the center of mass, just like two equal mass planets orbiting about each other (kind of like a Woodward governor). The scale is smaller than planets but the rotation rate is much higher. The gravity signal would be of a frequency much higher than the background noise. To show it is a gravity wave, measure signal intensity as a function of distance.

Pick a reasonable mass, a radius and a frequency. Also describe your detector. I'll calculate a signal strength for you.

[Physicist]

I said: Pick a reasonable mass, a radius and a frequency. Also describe your detector. I'll calculate a signal strength for you.

I couldn't resist. Assume a bar of mass 1000 kg, one meter in length, rotating at 1000 Hz. An order-of-magnitude calculation for the gravitational radiation power output is 10^-19 erg/s. I don't care what kind of detector you have, you won't measure it. An electron volt is of order 10^-12 erg.

[Petronski]

As the probability that Rosie O'Donnell will board a given flight moves from 0 to 1, the energy needs of that flight move from x to ininity.

[PatrickHenry]

Michelson-Morely is how we can measure Lorentz contraction.

That was good. Very good.

[Barry Goldwater]

Gauss's law looks at E perpindicular to the surface. The wire, or ion beam has an equal, but opposite E on both ends of the cylinder so it cancels in the integral. The E field that is responsible for the charge movement (whether it causes the charge to move or it is a result of it) exists in addition to the E of the charge and does not affect Gauss's law. You said it does. Please demonstrate.

[AngryAmerican]

All your gravity waves are belong to us.

[Barry Goldwater]

The MM experiment was performed in an accelerated reference frame, on the surface of the rotating earth. If the velocity of light is known to a high degree, how come east-west and west-east transit times over the same path (but opposite directions) are not equal?

[Barry Goldwater]

Thanks for the calculation, can you explain how you did it? If it is that low detection is improbable.

[Barry Goldwater]

My apologies. Your comment about Gauss's law being invalid in the presence of moving charge had me suspect. If I take a tennis ball put lots of charge on it and throw it will a stationary observer see only the static field of a collection of charge pass by? Will the charged tennis ball have any additional inertia due to the charge? Assume the charge has zero mass.

More importantly:

If I take a plastic torus that has charge fixed on the surface and spin it about its center axis will I see an E field due to this current/charge movement? (will it be in the direction of the current/ moving charge?) If so, this E field exists as a result of charge movement and no E field caused the charge to move,as no E field was ever applied, it was purely mechanical rotation. Will I see a magnetic field corresponding to this ring of current (revolving ring of charge)despite no applied electric field?

So I ask again, does moving charge create an additional E field?

[Physicist]

The E field that is responsible for the charge movement (whether it causes the charge to move or it is a result of it) exists in addition to the E of the charge and does not affect Gauss's law. You said it does.

Please review our exchange. You are the one who said that Gauss's law doesn't apply. All I've ever said is that Gauss's law does indeed apply, and is universal.

Before I correct you any further, perhaps you can tell me where you're going with all this? If you cut to the chase we can both save some time.

So what's your pleasure? Luminiferous Ether? Ritz emission theory? Electric universe? Autodynamics? C-decay?

[Barry Goldwater]

Here's the original:
I said:
"When an electron has velocity the total electric field increases over that of a stationary electron."
You said:
"No, it doesn't. That would violate Gauss's Law."

I showed it doesn't. When a voltage is applied to a wire the electrons move to counter the applied electric field. It is the electric field of the motion of the electrons that counters the applied field of the battery to drive the net internal field of the wire to zero. The is the same mechanism that drives the tangential E field on the surface of a conductor to zero for wave reflection calculations. I stand by what I said, the motion of charge creates an E field in addition to the static E field of a charge. This E field is in the direction of the charge and has a divergence of zero, unlike static charge. You had said I was wrong here. I don't believe so.

The mechanically rotating ring of charge, with the charge statically fixed to the ring also shows this. The movement of charge here is driven mechanically and an additional E field results in the direction of the charge motion. Faraday demonstrated this with moving polarized dielectrics. If you disagree, fine. It would be very helpful to show me where I'm wrong.

I'd like to learn more about the calculation and mechanism of the generation of gravitational waves. You seem quite knowledgeable on this subject and I'd like to rely on your expertise for references and help on this subject. I'd like to learn how you calculated the field of a propagating gravitational wave. Is it a shear wave, a longitudinal wave or something else? I

Wasn't the ether proven not to exist?

[Physicist]

The mystery comes into focus. From this thread:

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To: DoughtyOne

Seismology and Geology seem to create more pseudoscientific garbage than any other science besides medicine.

13 posted on 10/22/2002 2:28 AM EDT by John H K
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To: John H K

Not true! Ever read cosmology or quantum theories?

22 posted on 10/22/2002 10:31 AM EDT by Barry Goldwater
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[Barry Goldwater]

Mystery? Yes, I wrote that.

It was definitely a faux paus on my part to assert that Gauss's law is not invariant. It is, I was wrong to say that it did not apply to moving charge.

Are you going to admit that there is the additional E field of a moving charge?

You might be interested in terrestrial Thirring-Lense experiments. The experimental results make me question your gravitational energy calculations.

[Physicist]

Thirring-Lense experiments

Aha! You're one of those Tom Van Flandern (speed-of-gravity-is-infinite) proponents, right?

[Fiddlstix]

Bump

[Barry Goldwater]

No! Please, have a little respect for me. :)

Hint:
Have you ever heard of someone named Roland Dishington?

[Physicist]

No.

[PatrickHenry]

I think he's one of those anti-gravity guys.

[RightWhale]

An obscure critic of orthodoxy.