Still waiting to bag the big one
It was supposed to be the first great scientific discovery of the 21st Century - or so many researchers thought when they rushed down to the bookmakers to place bets at what were deemed at the time to be ludicrously generous odds.
The physicists believed that they were close to making the first direct detection of gravitational waves, the ripples in space-time generated by supernovas and coalescing neutron stars.
Their confidence was buoyed by the knowledge that colossal new machines in the US and Europe that were finally capable of making the crucial breakthrough were just coming online.
They simply couldn't believe their luck when a sceptical Ladbrokes offered to pay out £500 for every pound wagered if someone could bag a gravitational wave before 2010.
That was over five years ago. Today, just a few months shy of the decade's end, many of those same scientists report in the journal Nature that... er, um, they still haven't detected a gravitational wave.
I am being a bit tongue-in-cheek here because the international team's "non-detection" is actually a lot more remarkable than I make out - and I'll explain why in a moment.
But let me first back up a little and dwell on the significance of gravitational waves.
These elusive phenomena are an inevitable consequence of Einstein's theory of general relativity. If what we understand about Einstein's theory of gravity is correct - and we believe that it is - then they must be out there.
It is just a question of having the necessary sensitivity to detect them, because, unlike electromagnetic waves - the light we see all around us - gravitational waves are predicted to be extremely weak.
If one were to pass through your body, it would alternately stretch your space in one dimension while squashing it in another. Such changes, though, would be fantastically small.
Current Earth-based observatories hunting for this disturbance bounce lasers down L-shaped tunnels that are hundreds or thousands of metres long. They aim to find deviations in the experimental set-up that can be equivalent to one one-thousandth of the width of a proton, one of the particles that makes up all atoms.
There are a few of these facilities dotted around the globe - the Ligo network in the US, and the Geo 600 and Virgo establishments in Europe.
Any accelerating mass should send gravitational waves radiating outwards at the speed of light; but only really big events, such as exploding stars and merging black holes, are expected to disturb space-time sufficiently to register at the observatories.
Being able to routinely detect gravitational waves would bring a step change in astronomy.
It would allow scientists to probe those places where technology that is dependent on light - that is, traditional telescopes - cannot go: to the edges of black holes, for example; and back beyond when we think that the first light pushed out across the Universe, to the very first moments after the Big Bang.
The Big Bang itself ought to have produced copious gravitational waves, and these should still be washing over us even now. And this brings me back to that non-detection.
The fact that the Ligo and Virgo Collaborations haven't yet seen this background signal in their super-sensitive equipment is itself very interesting to scientists. That's because the strength of this cosmic hubbub should be directly related to the way the Universe was in the first minute after the Big Bang and the physics occurring at that time.
Put another way, the non-detection puts new, tighter limits on the models used by cosmologists to describe the earliest events.
The gravitational wave seekers will get there eventually. Their equipment is being upgraded to become even more sensitive. The detection may not come soon enough to wipe the smile off the bookmakers' faces; but it will come.
And I'll leave you with a new picture of Lisa Pathfinder (LP). This is a demonstration spacecraft being built in the UK. It's a forerunner to a very big Nasa/Esa mission that will attempt to detect the gravitational waves emitted when gargantuan black holes at the centres of galaxies merge.
LP should fly in 2011 to trial the critical technologies needed by the full mission.
The engineering involved is astonishing and I'll blog about it at a future date.
I’m 
© MMIX~RS~q~RS~~RS~z~RS~14~RS~)
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Like attempts at dark matter, it is about detecting what is not there. There is what is and there is what is not. The Buddhist call it Dependent Origination.
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"Their equipment is being upgraded to become even more sensitive. The detection may not come soon enough to wipe the smile off the bookmakers' faces; but it will come."
What makes you so confident? Do you have any numbers to back this claim up? How sensitive will the new equipment be, and what lower limit do we have on how faint the gravity wave background could be?
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The BIG ONE IS NEVER GOING TO COME. See Press Releases and Significant Findings:
There's not a shred of evidence for a direct interaction between light and gravity in empty vacuum space; a significant finding of modern Astrophysics
Recent findings in observational Astrophysics convincingly show that the important fundamentals of Mathematical Physics and astrophysical observations have been incorrectly applied to the so-called gravitational lenses. Since the discovery of solar light bending, researchers have always assumed that gravitational lenses are due to a direct interaction between light and gravity. Historically, astronomers have noted that light rays from stars that pass near the rim of the sun appear to deviate from their linear trajectories. New evidence now shows that all the astronomical observations on the effects of the gravitational lenses of the light rays from the stars have been due to an indirect interaction between light and gravity and not due to direct interaction. Apparently, a direct interaction between the gravitational field of the sun and the rays of light from the stars in empty space just above the solar plasma rim does not take place at all.
A recent press release: http://www.pr-inside.com/important-fundamentals-and-astrophysical-observati-r1382324.htm
En Españal: Comunicacion de prensa: [Unsuitable/Broken URL removed by Moderator]
Detalles: http://www.extinctionshift.com/SignificantFindings.htm
A paper on this subject has been published in the renown refereed journal Astronomische Nachrichten, "Time resolved images from the center of the Galaxy appear to counter General Relativity", Dowdye, Jr., E.H., Astronomische Nachrichten, 328, Issue 2, 2007, pp 186 -191
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Solid evidence shows that a direct interaction between gravitation and electromagnetism does not take place.
Mainstream researchers seem to ignore three (3) observational facts in Astrophysics supported by sound fundamentals in Mathematical Physics
· Unseen evidence of Gravitational lensing in the Vacuum Space just slightly above the Solar Plasma Rim revealed by applying Gauss' Law to Gravitation
· Unseen evidence of Einstein Rings in a sky of countless numbers of stars where the lens and the source are by good chance co-linearly aligned with the observer
· Unseen evidence of Gravitational lensing in the intensely observed images of stars orbiting about the super massive black hole at Sagittarius A*
There is now solid evidence that a direct interaction between gravitation and electromagnetism does not take place.
ABSTRACT "Time resolved images from the center of the Galaxy appear to counter General Relativity", Dowdye, Jr., E.H., http://adsabs.harvard.edu/abs/2007AN....328..186D
For decades now some very important fundamental principles of mathematical Physics have been incorrectly applied to the theory of gravitational lensing or just simply ignored. From astrophysical observations it is apparent that the current understanding of the effects that gravitation should have on light is fundamentally incorrect. Astrophysical observations pertaining to lensing are consistent with effects due to an indirect interaction involving an interfering media, not a direct interaction taking place in vacuum space. It is however theoretically possible that current technical means may not permit a distinction to be made between an indirect and a direct interaction between gravitation and light. The thin plasma atmosphere of the sun represents an indirect interaction between the gravitational field of the sun and the rays of light from the stars. There is convincing observational evidence that a direct interaction between light and gravitation is yet to be observed. Historically, the observed evidence of light bending occurred predominantly near the plasma rim of the sun, not in the vacuum space far above the rim. The events taking place at the site of Sagittarius A* presents convincing observational evidence that a direct interaction between rays of light and gravitation in vacuum space simply does not take place. This is clearly revealed in the time resolved images of the rapidly moving stellar objects orbiting about Sagittarius A*, a region at the galactic core believed to be a super massive black hole. This is a region that has been under intense observations by the Astrophysicists since 1992. A clear lack of observational evidence for optical lensing due to gravitation is apparent when examining the undistorted images of the stars moving along Keplar paths about Sagittarius A*. The space in the immediate vicinity of a black hole is by definition an extremely good vacuum. The evidence for this is clearly seen in the highly elliptical orbital paths of the rapidly moving stars orbiting about the galactic core mass. The presence of any material media near the galactic core mass would conceivably perturb the motion of the stellar object s16 moving with fractional light velocities, thus causing it to rapidly disintegrate. Astrophysical observations reveal that s16 has a velocity approaching 3 % of the velocity of light when passing to within a periastron distance corresponding to 60 astronomical units from the black hole thus giving solid evidence that the space in this region has to be, without a doubt, an extremely good vacuum. It follows from this that a direct interaction between the light emitted from the orbiting stars and the gravitation of this super massive galactic core at the site of Sagisttarius A* is yet to be observed.
For details see: http://www.extinctionshift.com/SignificantFindings.htm
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Many parts of the physical World are well beyond the understanding of most physicists let alone members of the public. For example whilst I think I understand the overall ideas behind the 11 dimensional m-brane model of the universe but I can't even do the maths of 10 dimensional string theory. (I would love to be able to do and understand the maths and it always amuses me to react to the British Government's advert for helping people who need help with their maths to ask for a course on the subject! - It wasn't even a theory when I did my first degree in physics !) Now the reason, as I understand things, that gravitational waves are a phenomena that might be of interest is that these and other phenomena are predicted by these mathematical models and thus by finding them the theory can be supported, or not.
This raises an important question: does not observing these phenomena disprove the theories or cause the theories to be modified? Personally, my concerns with the general state of physics (and I have acknowledged an (historic) interest in the subject) is that most of its theories are being propounded by old men, not young ones - when traditionally it has been the young (under mid 20's) that have provided the major advances in the subject, and of our understanding. Is the theoretical model fully correct as a description of the universe? My personal opinion is no, but, as I have said before, the maths worries me as I do not have the tools to actually manipulate the 11 dimensional systems and thus the ability to analytically criticise the theory. My limited understanding of the maths does point to the possible 'fact' (if the theory is righish) that gravitational waves are only microscopic energy fluctuations with the tiniest capacity to carry any information with detection being so very problematic from our possible frames of reference to make it almost impossible.
[Other things is the currently widely accepted model of the universe that bother me include the big bang - I just don't see that the maths of the model indicates a single big bang at all and I further do not see that solutions to the relevant equations do not preclude multiverses with multiple big bangs. I am also perturbed by the limiting understanding of observability, time and causality. - I dare say that these things will puzzle untold generations to come.]
I would add that the study of theses things is a very valuable activity to everyone as we do not know what will come of it and in a very real sense it is exploration.
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EHDowdye wrote:
"Solid evidence shows that a direct interaction between gravitation and electromagnetism does not take place."
EHDowdye seems to have misunderstood a basic part of the Theory of Relativity - NO-ONE claims that gravity affects light DIRECTLY.
Light has no mass, so gravity does not act upon it. It DOES, however, propagate through space-time.
The Theory of Relativity predicts that large masses will distort space-time sufficiently that light passing near to them will APPEAR TO BE 'bent' by gravity, because it has followed its (not-bent-by-gravity) path through a region of space-time that HAS been 'bent' by the gravitational effect of the very large mass.
The Theory also predicts that major disturbances of very large masses will produce detectable 'gravitational waves' - or, if you prefer - 'ripples in space-time' - and it is these waves that the LIGO machines have been built to detect.
I'm not quite sure what EHDowdye is driving at with the remainder of his comments after his initial statement (the bit that shows he has not understood the science upon which he is commenting) but, given that he is criticising a position that NO-ONE holds, he is attacking a 'straw man'.
In his second post, he cites three examples that (according to him) do not show any gravitational lensing.
Gravitational lensing has, of course, been observed in many other instances.
On the website of the Hubble Space Telescope, one can even see photographs of it:
http://hubblesite.org/newscenter/archive/releases/exotic/gravitational-lens/
His(?) comment "The space in the immediate vicinity of a black hole is by definition an extremely good vacuum" is also just not true - the space around a Black Hole often contains an 'accretion disk' of materials 'swirling around the plughole'. If there is a lot of material in the accretion disk, it can become superheated as it swirls ever faster around the Black Hole, and it then gives off enormous amounts of energy in two jets directed at 90° to the 'poles' of the Black Hole. These plasma jets continue for mind-boggling distances, and are highly visible in the X-ray spectrum.
EHDowdye's comment "the evidence for this is clearly seen in the highly elliptical orbital paths of the rapidly moving stars orbiting about the galactic core mass" is another complete non-sequitur that demonstrates his lack of understanding of the subject - the highly elliptical orbits of objects near very massive objects *actually* indicate the high strength of the gravitational field exerted by the object.
The high degree of ellipticity of these orbits offers **no evidence whatsoever** about the 'quality'/strength/degree of vacuum around the Black Hole.
He finishes by repeating his claim that "a direct interaction between the light emitted... ...and the gravitation... ...is yet to be observed" - which is, again, an attempt to disprove a claim that NO-ONE makes.
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John-from-Hendon asks the question "does not observing these phenomena disprove the theories or cause the theories to be modified?".
He says that he has a first degree in Physics. If that is true, he should know that the basic premise of modern Science is that, if the observations disagree with the Theory, then the Theory has to be modified.
If he is asking whether these observations *on their own* are sufficient to demand modification of the Theory of Relativity, then I would say that they are not. If several, more sensitive, detectors are built, and NONE of them observe any 'gravitational waves', then that might cause a re-examination of the Theory - but one negative observation on its own cannot kill a Theory.
E.g. if I travel to the Sundarbans and fail to see any tigers, have I proved that no tigers live there? No.
But, if *many* people explore the forests, and NONE of them see any tigers, it *then* might be reasonable to say that there are no more tigers there.
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#7. JohnnyParanoia wrote:
"He says that he has a first degree in Physics. If that is true, he should know that the basic premise of modern Science is that, if the observations disagree with the Theory, then the Theory has to be modified."
Sorry, but your childlike simplistic view of 'science' is just that. Paradigm shift in science is the result of the slow shift of generally accepted theory and takes time and does not move in the simplistic manner that you think. That was true in the past and it is true today. Your simplistic criticism suggests that you have very little grasp of the real world of science and the way in which accepted theory evolves. The way that you write strongly indicates that you possess only a childlike 'black and white' view of the world and more especially of science - and I am strongly tempted to add - leave it to people who understand!
Your unsubtle explanation of the way in which 'one negative observation on its own cannot kill a theory' is absolute rubbish, firstly because of the absolutism of the 'one' and secondly the lack of your understanding that it depends on the nature of the contraindication.
Let me also rip apart your simplistic and wrong view of the way in which science actually works - but I haven't the space to re-educate someone like you - but try reading up "Schrödinger's Cat", and then on the sociology of scientific paradigm change - where in, simplistic summary, it is found that an individual scientist tends to hold a theory to be true for as long as he/she has already held it to be true and then this works through to the body of scientific opinion.
I repeat, for the umpteenth time: scientific paradigm shift in what is an acceptable and accepted theory in proper science is as much a social phenomena amongst the group of scientists, as it is driven by 'facts' this is as true in physics and maths as it is in the far less rigorous fields that use a claim of scientific method as a way of the self justification of the 'value'. (e.g. economics)
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This is becoming as heated as the Climate Change discussions. Quick, someone measure the energy. Just had a gravitational wave bounce off one of those post. Quantum physics.......observer impact results...all probabilities exist.
Concept to consider: no beginning and no end.
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