Einstein's theory fights off challengers (article)

Two new and independent studies have put Einstein's General Theory of Relativity to the test like never before. These results, made using NASA's Chandra X-ray Observatory, show Einstein's theory is still the best game in town.

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The first finding significantly weakens a competitor to General Relativity known as "f(R) gravity."

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Schmidt and colleagues used mass estimates of 49 galaxy clusters in the local universe from Chandra observations, and compared them with theoretical model predictions and studies of supernovas, the cosmic microwave background, and the large-scale distribution of galaxies.

They found no evidence that gravity is different from General Relativity on scales larger than 130 million light years. This limit corresponds to a hundred-fold improvement on the bounds of the modified gravitational force's range that can be set without using the cluster data.

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A second, independent study also bolsters General Relativity by directly testing it across cosmological distances and times. Up until now, General Relativity had been verified only using experiments from laboratory to Solar System scales, leaving the door open to the possibility that General Relativity breaks down on much larger scales.

To probe this question, a group at Stanford University compared Chandra observations of how rapidly galaxy clusters have grown over time to the predictions of General Relativity. The result is nearly complete agreement between observation and theory.

"Einstein's theory succeeds again, this time in calculating how many massive clusters have formed under gravity's pull over the last five billion years," said David Rapetti of the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) at Stanford University and SLAC National Accelerator Laboratory, who led the new study. "Excitingly and reassuringly, our results are the most robust consistency test of General Relativity yet carried out on cosmological scales."

Source

Relativity has been getting a bad rap around here recently, so, here's this. There's a very strong case to be made for Einstein's theories; their predictive power is unrivaled by any other formalized physical theory at cosmological scales. Because of their predictive and descriptive successes, support of these theories is certainly justified. It's one thing for the "plasma cosmologists" among you to point out anomalous quasar observations, but GR is by no means worthless. Einstein provided real, workable equations that we can test, which are much more useful than an abstract conceptual notion of an "electric" or "holographic" universe. The corresponding mathematical formalizations of these alternative cosmological theories are less than impressive.

If GR is wrong, how do you account for the accuracy of the equations premised on the relativistic understanding of the universe? It's not like Einstein made some abstract metaphysical suggestion. His theories are highly specific in their predictions, and their associated equations leave little room for subjective interpretation. Correct, highly specific predictions are not likely to arise from fiction.

Anyway, I'm sure that those of you who are set in your ways will not be compelled by this stuff. However, you should be aware that GR has a huge head start over anything else. You've got a long way to go with any fundamentally different cosmology in terms of observational/experimental verification/confirmation. Any alternative cosmology will have to account for all of these observations at least as well as relativity, and then go on to account for additional observations that GR cannot account for. Physics is results based, and your task is monumental.

[edit on 4/18/10 by OnceReturned]

I agree 100%. Einstein is right. (General Relativity is the most astonishing breakthrough---to be discovered in 1917, without significant pre-existing experimental evidence, instead of 1957 is outrageous genius)

Except the "holographic universe" as pursued by actual physicists does involve a real physical theory. It's not yet in an acceptably complete form by any means but it is real.

In a nutshell it is a theory of cosmological quantum gravity where the effects in N dimensions are actually computable on a surface of N-1 dimensions.

It's therefore holographic in the the specific sense of holography where 3-d patterns of light are encoded carefully on a 2-d transmission photograph.

It isn't some woo-woo mystical business.

BTW, Leon Lederman originally wanted to call his book on the search for Higgs "The God Damn Particle". Publisher took out the "damn"---but really there is nothing mystical or religious in the slightest any more than an intermediate vector boson.

[edit on 18-4-2010 by mbkennel]

reply to post by OnceReturned


Part of the ideas and the general argumentation behind holographic universe and similar theories is the obvious rationality and predictability of this world we live in, and Eintein's general relativity and it's siblings sows atleast to me how these theories have found their perfect application in these "still fictional" theories, and all the "Theories of Everything" which surround us these days. Like you point out between the lines, we can't even imagine this world we live in today without Einsteins theories about the relationship between energy and matter, gravity and light etc. Most people just don't see the woods since there is a giant tree blocking the view. I don't see any disagreement between things as far appart as intelligent design, General Relativity, strict genetic algoritms, holographic universe and quantum mechanics. They are all ways to explain elements of the same things in my mind, that whatever or whoever designed or resulted in this reality bases or is based on an incredibly rational and straight forward, imaginitive and quite beautyful and amazing norms and laws.

reply to post by OnceReturned


Well well well where to begin with this one.

First off, the measurements of galaxies showing gravity is constant by looking at galaxies is based on the assumption that gravity is indeed a cosmological constant and that galaxies themselves are held together by gravity alone.

Given that scientists must add dark matter, which has never been proven to exist, to their galaxy models in order to make them work, the assumption that gravity alone is the force that's holding galaxies together is a hypothesis, not a fact.

Further, measurements of gravity here on earth have all shown that gravity changes over time. No measurement of gravity here on earth has proven gravity to be a constant force.

Measurements using beam balances showed a variation by as much as 1% over time. Measurements using atom interferometry also showed variation outside standard deviation. Further, atom interferometry is a ridiculous tool to use to measure gravity considering atomic scale structures are governed by special relativity.

So we have actual verifiable proof that gravity is NOT constant as it is measured here on earth. We also have no proof of dark matter, which is required for the galaxy models hypothesized to be correct.

This pretty much blows Einstein's theories out of the water.

By saying "Einstein's theories fights off challengers" - they are referring to other gravity-centric models, which are just as ridiculous as Einstein's.






[edit on 20-4-2010 by mnemeth1]

reply to post by mnemeth1


And I thought Einstein called his own idea about the cosmological constant for "his greatest mistake ever". That gravity varies on Earth should not be used to dismiss Einstein, there are many things working, and there being a constant one could use to explain gravity doesn't mean gravity itself can't vary. A simple thing like temperature makes matter change gravity's influence to matter. Hot air balloons is a simple way to show this.

[edit on 20/4/2010 by Neo Christian Mystic]

Originally posted by mnemeth1
reply to post by OnceReturned

 

Well well well where to begin with this one.

First off, the measurements of galaxies showing gravity is constant by looking at galaxies is based on the assumption that gravity is indeed a cosmological constant and that galaxies themselves are held together by gravity alone.

Given that scientists must add dark matter, which has never been proven to exist, to their galaxy models in order to make them work, the assumption that gravity alone is the force that's holding galaxies together is a hypothesis, not a fact.

Further, measurements of gravity here on earth have all shown that gravity changes over time. No measurement of gravity here on earth has proven gravity to be a constant force.

Measurements using beam balances showed a variation by as much as 1% over time. Measurements using atom interferometry also showed variation outside standard deviation. Further, atom interferometry is a ridiculous tool to use to measure gravity considering atomic scale structures are governed by special relativity.

So we have actual verifiable proof that gravity is NOT constant as it is measured here on earth. We also have no proof of dark matter, which is required for the galaxy models hypothesized to be correct.

This pretty much blows Einstein's theories out of the water.

By saying "Einstein's theories fights off challengers" - they are referring to other gravity-centric models, which are just as ridiculous as Einstein's.






[edit on 20-4-2010 by mnemeth1]

Quoted for Truth!!!!
This could very well be the post of the year!

Are you serious?

Originally posted by mnemeth1
reply to post by OnceReturned

 

Well well well where to begin with this one.

First off, the measurements of galaxies showing gravity is constant by looking at galaxies is based on the assumption that gravity is indeed a cosmological constant and that galaxies themselves are held together by gravity alone.

Given that scientists must add dark matter, which has never been proven to exist, to their galaxy models in order to make them work, the assumption that gravity alone is the force that's holding galaxies together is a hypothesis, not a fact.

Further, measurements of gravity here on earth have all shown that gravity changes over time. No measurement of gravity here on earth has proven gravity to be a constant force.

Measurements using beam balances showed a variation by as much as 1% over time. Measurements using atom interferometry also showed variation outside standard deviation. Further, atom interferometry is a ridiculous tool to use to measure gravity considering atomic scale structures are governed by special relativity.

So we have actual verifiable proof that gravity is NOT constant as it is measured here on earth. We also have no proof of dark matter, which is required for the galaxy models hypothesized to be correct.

This pretty much blows Einstein's theories out of the water.

By saying "Einstein's theories fights off challengers" - they are referring to other gravity-centric models, which are just as ridiculous as Einstein's.






[edit on 20-4-2010 by mnemeth1]

Originally posted by Grifter.be
Are you serious?

Originally posted by mnemeth1
reply to post by OnceReturned

 

Further, measurements of gravity here on earth have all shown that gravity changes over time. No measurement of gravity here on earth has proven gravity to be a constant force.

Well mnemeth1 is right about dark matter, that's unaccounted for. The only problem is he doesn't have a better theory, the alternatives he proposes have even bigger problems than the dark matter problem.

Regarding gravity, he's right that there is some controversy however I don't agree with his assumption that it's gravity that varies when it could in fact be a measurement problem. We are working on new methods to get more accurate measurements of gravity as this article discusses:

The Controversy over Newton's Gravitational Constant

The fact that this famous fundamental constant is still so uncertain testifies to the difficulty of gravitational measurements. The recent flurry of new ideas for measuring G would surely have pleased Isaac Newton (quite a clever experimenter himself) who started this whole enterprise over 300 years ago.

reply to post by mnemeth1


So we meet again. . .

I suspected that this would show up on your radar as something worth criticizing because it adds to the experimental support for a cosmology which is mutually exclusive with your own. I'll play the fully indoctrinated, naive, and misguided supporter of the mainstream paradigm. . .

First off, the measurements of galaxies showing gravity is constant by looking at galaxies is based on the assumption that gravity is indeed a cosmological constant and that galaxies themselves are held together by gravity alone.

The only assumptions that the measurements themselves are based on are the trivial ones which plague all measurements: that the measurement decives are not malfunctioning, that the scientists aren't hallucinating, and our guiding notion that when we measure something we are really measuring something "out there" in reality that exists, and not being deceived by a hologram or dream or Matrix-like situation.

The measurement itsef is nothing more than an observation. When we look at the galaxies in question, we observe them to be in certain locations. This is not really a matter of opinion; anyone can make the same observations with the same equipment. The issue that is open to debate is the one of how to interpret these observations. It is the interpretation which these scientists make that is based on existing beliefs; what you call assumptions. You claim two assumptions: that gravity is constant across space and time, and that gravitational forces are the only attractive forces applicable here. In fact, neither of these claims are assumptions. They themselves are the results of the experiments; the interpretations of the observations. They are not the assumptions which underly the interpretations.

Relativistic gravity isn't taken to be constant here, it is found to be: the predictions made based on GR about what to expect when we look at these galaxies are verified, the experimental observations are in agreement with the theoretical predictions. This not an assumption, this a test of an assumption, and the assumption turned out to be right. If you assume GR to be true and based on that theory calculate where you should find these galaxies your results will turn out to be almost exactly where the galaxies actually are.

You're claim about the second assumption may be correct, but it follows from a very fundamental methodological philosophy which is used in all of science. The result of this experiment is that the positions of these galaxies are in agreement with their theoretical positions as predicted by GR. The purpose of the experiment is to determine whether or not relativistic gravity holds true at much larger scales than have ever been tested before. The scientists interpret their results as confirmation that it does. Your counter-argument is to say that what might be happening is that gravity is not actually consistent across these scales, but that some other unidentified force in addition to the force of gravity(which, by itself, would be too strong or too weak according to you) is needed to explain what we're seeing. Why propose this additional mystery force, though, if the predictions of GR are accurate by themselves? We have one set of equations(the gravity equations in GR) which accurately describe what we're seeing. You suggest that we those equations are wrong and that we should look for a combination of forces in order to explain what we're seeing. Why? This is a violation of Occam's Razor. We cannot be justified in proposing additional complexities in order to explain observations which are perfectly consistent with a much simpler theory. Do you suppose that it is coincidence that GR get's these predictions right? There is no reason to reject our single force theory in favor of a combination of forces when the single force theory accounts for our experimental results. Likewise, there is no reason to suspect that that single force(gravity) is secretly the net result of a multitude of other forces. If one theoretical entity can account for everything, that theory is to be prefered.

The assumptions that you accuse the scientists of making on not assumptions, but are test results. The theory of GR was tested on scales of unprecedented enormity and was confirmed: its predictions came true. This specific attack of yours is not a very compelling one. I know you think GR is bogus, but you ought to give credit where credit is due. These observations are consistent with GR. These experiments are valid, and the problems which you pointed out in the quoted text above are really not problems. This is a classic case of testing a theory, and your opposition is based on unfounded methodological hang ups and a misinterpretation of the relationship between observation, interpretation, and theory.

[edit on 4/20/10 by OnceReturned]

I'd have to agree with the above posters - this so-called verification assumes Dark Matter is - and behaves - as they guesstimate.

I can also prove my theory of moddified gravity is true - at large distances - when you consider the properties of "invisible matter" (TM) that I have just made up!



Not calling total b.s. on this yet - I just am still very skeptical about Dark Matter being used as an assumed property of these systems.

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