Correlating Gravitational Wave Production in LIGO


Drawing by Glen Edwards, Utah State University, Logan, UT

The most important thing is to be motivated by your own intellectual curiosity.KIP THORNE

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Fig. 1. The four forces (or interactions) of Nature, their force carrying particles and the phenomena or particles affected by them. The three interactions that govern the microcosmos are all much stronger than gravity and have been unified through the Standard Model

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Dr. Kip Thorne, Caltech 01-Relativity-The First 20th Century Revolution

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Why are two installations necessary?


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See: LIGO Listens for Gravitational Echoes of the Birth of the Universe

Results set new limits on gravitational waves originating from the Big Bang; constrain theories about universe formation

Pasadena, Calif.—An investigation by the LIGO (Laser Interferometer Gravitational-Wave Observatory) Scientific Collaboration and the Virgo Collaboration has significantly advanced our understanding of the early evolution of the universe.

Analysis of data taken over a two-year period, from 2005 to 2007, has set the most stringent limits yet on the amount of gravitational waves that could have come from the Big Bang in the gravitational wave frequency band where LIGO can observe. In doing so, the gravitational-wave scientists have put new constraints on the details of how the universe looked in its earliest moments.

Much like it produced the cosmic microwave background, the Big Bang is believed to have created a flood of gravitational waves—ripples in the fabric of space and time—that still fill the universe and carry information about the universe as it was immediately after the Big Bang. These waves would be observed as the “stochastic background,” analogous to a superposition of many waves of different sizes and directions on the surface of a pond. The amplitude of this background is directly related to the parameters that govern the behavior of the universe during the first minute after the Big Bang.

Earlier measurements of the cosmic microwave background have placed the most stringent upper limits of the stochastic gravitational wave background at very large distance scales and low frequencies. The new measurements by LIGO directly probe the gravitational wave background in the first minute of its existence, at time scales much shorter than accessible by the cosmic microwave background.
The research, which appears in the August 20 issue of the journal Nature, also constrains models of cosmic strings, objects that are proposed to have been left over from the beginning of the universe and subsequently stretched to enormous lengths by the universe’s expansion; the strings, some cosmologists say, can form loops that produce gravitational waves as they oscillate, decay, and eventually disappear.

Gravitational waves carry with them information about their violent origins and about the nature of gravity that cannot be obtained by conventional astronomical tools. The existence of the waves was predicted by Albert Einstein in 1916 in his general theory of relativity. The LIGO and GEO instruments have been actively searching for the waves since 2002; the Virgo interferometer joined the search in 2007.

The authors of the new paper report that the stochastic background of gravitational waves has not yet been discovered. But the nondiscovery of the background described in the Nature paper already offers its own brand of insight into the universe’s earliest history.


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3 Responses to Correlating Gravitational Wave Production in LIGO

  1. Phil Warnell says:

    Hi Plato,You remarked what’s quoted below on Backreaction and I thought it more appropriate I address it here. “While considering the standard model and the integration of gravity within that context, it is not an un-noble thing to "find a time" where all four forces are considered one?” Yes as long as the other option is considered, as to not have what we recognize as the consequences of gravity regarded as a force at all. The gist of GR is to have things simply follow a course mandated by the path presented. This has gravity not as a force (as conventionally considered), but rather as a course mandated by space-time architecture relative to the inertial properties of the object considered. In some respects it’s like insisting a train track being a force, rather than simply a path. Of course this becomes more complicated, for GR is interrupted as a field theory, as all of the other forces have been framed as being, only in this case the nature of the media in which the field is formed was never first considered as quantilized or has it thus far shown to have such a character, in respect to any proposed and supporting demonstrated experiment. Just so you are aware, I have no firm opinion as to whether space-time is actually quantilizable or not. All I’m saying is when one is looking for something and it continues to elude, that it should be seen also as a reasonable explanation that it’s not there to be found. There have been many times when the alternative has been resisted, such as in maintaining the universe of Ptolemy, the existence of the planet Vulcan or that of the ether. It’s just that in as the strength of science rests with the maintenance of doubt, that the prospect that something doesn’t exist should be at least be considered as equally likely that it does, in terms of experimental outcome. That is to be mindful that what science represents being is a methodology to reveal the truths of nature, rather than one to have nature be as we consider it should be.Best,Phil

  2. Plato says:

    Hi Phil,After Einstein's death, the torch of unification passed to other hands. In the 1960's, the Nobel Prize-winning works of Sheldon Glashow, Abdus Salam and Steven Weinberg revealed that at high energies, the electromagnetic and weak nuclear forces seamlessly combine, much as heating a cold vat of chicken soup causes the floating layer of fat to combine with the liquid below, yielding a homogeneous broth. Subsequent work argued that at even higher energies the strong nuclear force would also meld into the soup, a proposed consolidation that has yet to be confirmed experimentally, but which has convinced many physicists that there is no fundamental obstacle to unifying three of nature's four forces.For decades, however, the force of gravity stubbornly resisted joining the fold. The problem was the very one that so troubled Einstein: the disjunction between his own general relativity, most relevant for extremely massive objects like stars and galaxies, and quantum mechanics, the framework invoked by physics to deal with exceptionally small objects like molecules and atoms and their constituents.Time and again, attempts to merge the two theories resulted in ill-defined mathematics, much like what happens on a calculator if you try to divide one by zero. The display will flash an error message, reprimanding you for misusing mathematics. The combined equations of general relativity and quantum mechanics yield similar problems. While the conflict rears its head only in environments that are both extremely massive and exceptionally tiny — black holes and the Big Bang being two primary examples — it tells of a fissure in the very foundations of physics.See: Universe on a String No doubt the gist of things is to keep tabs of where things rest currently and see where views on this issue are being provided on a platform for examination today.So what are the prevailing thought on QGP as it deals with the issues of "continuity in expression" versus some "discrete notion of what a photon measures becomes" blended with gravity as a sign of a progressive view about what space can mean in that colorful world?For me it is ever the pursuit, still, that one might not have gone off the deep end to say that the predecessors of research were dealing with unfathomable reasoning about the reality with which they lived? That they could not have foreseen "experimental opportunities." To not address the micro-blackhole opportunity revealed in the LHC attempts at interpretation of a "beginning point" for all "that existed before" exists now in this universe? The detection of gravitational waves offers a completely new perspective on the universe: they will enable us to "hear" the cosmic orchestra as well as to see it! GR17 will provide the scientific community with one of the earliest opportunities to discuss the first scientific results of this era. It's resulted in muon detection attributes that are dealing with a much "finer point of view" then what lasted in views of the macroscopic world.So while you are sitting on the fence sort to speak, I too feel that resulting computerize programming sorting LIGO and SNO info seems as though the programs written are in themself speaking for what we want to observe rather then, what nature herself reveals, needs to be thought about more in my own mind about providing the framework for the results we want to see? So I have this "problem too" that must be dealt with.Best,

  3. Phil Warnell says:

    Hi Plato.The bottom line for me in this being despite all the effort thus far, gravitational waves have not been detected. So the weight of evidence at present suggests that they don’t exist or at the very least we should discover or consider how they elude our probing. I’m then somewhat sympathetic to Len Aderman’s view that nature in some respects has set it up that we will never know the truth of it all, beyond the truth that this forms to represent. However, I feel the many worlds approach on the human level has people to feel they are creatures of uncontrollable destiny, rather than entities that are able to choose a path even though it be one without full knowledge of what it will achieve. In essence that is the Metaphysical difference between theories like ‘Many Worlds’ and those like ‘Bohmian Mechanics’. That’s why I prefer the latter for although knowledge is mandated to remain incomplete, it still exists and can be accessed in part and be useful in having us choose our path. I like to think of it as the subtle difference found between the concept of fate and that of Karma.Best,Phil

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