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?"

[Barry Goldwater]

If you apply the Hiesenberg Uncertainty Principle to the MM experiment you get a surprise. Look at each fringe pattern as the interaction of two discrete photons. Assume the observation length is one wavelength so the observation time delta t is 1/f. f = frequency of light. We know E = hf ----> delta E = h delta f.
Now delta t times delta E = 1/f x h x delta f.
The principle states:
delta t x delta E ~ h, by substitution:
(delta f)/f ~1; This says the uncertainty of frequency is the frequency itself if one observes single fringe shifts. Since multiple fringe shifts are the products of many different photons (each having their own uncertainty) doesn't Hiesenberg UP say the null result, or any result for that matter is invalid?
To get a proper result the interference pattern of two photons must be observed over very many fringes. Am I off base here? How do I properly apply the HUP to MM?

[Barry Goldwater]

So we can neglect the rotational velocity at the surface of the earth due to its rotation?

[RadioAstronomer]

Punctured Trojan bump.

ROFL!

Did you get my freep mail on that link I sent?

[RadioAstronomer]

The contraction is due to the perspective from different inertial frames. A person looking at a yardstick from the side will see it as a long object, while a person looking at it from the end will see it as a short object. The Lorentz transformation is analogous to this effect of rotation, except that it describes a transformation between space and time, rather than the rotation of one space axis into another.

Very nicely said. May I borrow this? :-))

[Barry Goldwater]

Physicist:
If the E field lines of a moving charge do bend opposite the motion to form "streamlines" then I have to concede that an additional E field does not appear when the electron moves. What happens is the existing coulombic E lines rearrange themselves to oppose an applied field (by moving the charge) and for motion not due to an external field the lines rearrange to give an net E vector opposite the motion. The charge still meets Gauss's law and other observations. To me this is the simplest and most intuitive explanation and the more I think about it the better it sounds.
You may still believe the field lines are rigidly attached to the charge and extend as straight lines outward as the charge moves, but I don't think it's so.
Anyway, you are right that no new E appears. To me its simply a natural shift of the radial field to some other geometry in response to motion. Anyway, thanks for the head banging, I owe you a beer.

[gitmo]

They surf?

[PatrickHenry]

So we can neglect the rotational velocity at the surface of the earth due to its rotation?

I don't believe it's involved in the presumed motion of the interferometer through the aether, which is what the MM experiment was designed to detect. Only our motion around the sun would be relevant.

[ThinkPlease]

Oh, how I love relativity bump. The three things I wish I had more time to learn or relearn, relativity, cosmology, and an OO programming language other than C++.

[PatrickHenry]

God Bless America placemarker

[Physicist]

I'm afraid your posts are getting less comprehensible, aside from some obviously incorrect statements such as,

What happens is the existing coulombic E lines rearrange themselves to oppose an applied field (by moving the charge) and for motion not due to an external field the lines rearrange to give an net E vector opposite the motion.

In any case, I don't see where you're trying to go with any of this, or how it ties in to gravitational waves.

Instead of trying to puzzle out basic E&M from the top of your head, I suggest you start with a good undergraduate textbook such as Electricity and Magnetism by Edward Purcell or Electromagnetism: Principles and Applications by Lorrain and Corson, and study it. There's far more in either of those books than I could ever type in for you on FR.

[PatrickHenry]

Dead thread? Oh well ...

Vote! Bash the dems!
God Bless America!

[SunkenCiv]

Note: this topic is from 2002!!!