Comments on: New Way to Measure Curvature of Space Could Unite Gravity Theory http://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/ Space and astronomy news Sat, 20 Mar 2010 03:29:21 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Lawrence B. Crowellhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70315 Lawrence B. Crowell Wed, 02 Sep 2009 14:58:53 +0000 http://www.universetoday.com/?p=38858#comment-70315 Bending of light is by plain Newtonian gravity using the E = mc^2 from special and E = hbar*omega from de Broglie's relation. It would bend by half the amount.If gamma departs from unity the consequences might be very deep. It frankly could mean that there is no rational schema for gravitation. On the other hand it could signify departures of some other subtle nature, such as the brans-Dicke scalar modification of the tensors in general relativity.LC Bending of light is by plain Newtonian gravity using the E = mc^2 from special and E = hbar*omega from de Broglie's relation. It would bend by half the amount.

If gamma departs from unity the consequences might be very deep. It frankly could mean that there is no rational schema for gravitation. On the other hand it could signify departures of some other subtle nature, such as the brans-Dicke scalar modification of the tensors in general relativity.

LC

]]> By: Torbjorn Larsson OMhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70314 Torbjorn Larsson OM Wed, 02 Sep 2009 14:43:08 +0000 http://www.universetoday.com/?p=38858#comment-70314 Sorry Nancy and Lawrence, I'm with Yoo and Astrofiend in this. Wouldn't a different value in gamma come from another action, which in turn would putatively yield another nonperturbative theory and other particles?Or is there any significance in using gravitons (for free from string theory)? I don't get it.Meanwhile, another test GR passed with relative ease.Nitpick: "Bending of starlight by gravity was predicted by Albert Einstein when he published his theory of General Relativity in 1916."Bending of starlight by gravity is (and probably was) also predicted from special relativity, but only half as much as seen, as soon as you have the SR energy-mass equivalence to use on photons. Sorry Nancy and Lawrence, I'm with Yoo and Astrofiend in this. Wouldn't a different value in gamma come from another action, which in turn would putatively yield another nonperturbative theory and other particles?

Or is there any significance in using gravitons (for free from string theory)? I don't get it.

Meanwhile, another test GR passed with relative ease.

Nitpick:
"Bending of starlight by gravity was predicted by Albert Einstein when he published his theory of General Relativity in 1916."

Bending of starlight by gravity is (and probably was) also predicted from special relativity, but only half as much as seen, as soon as you have the SR energy-mass equivalence to use on photons.

]]> By: Lawrence B. Crowellhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70309 Lawrence B. Crowell Wed, 02 Sep 2009 12:19:27 +0000 http://www.universetoday.com/?p=38858#comment-70309 This is a test of general relativity and on the outset it appears to have nothing to do with quantum mechanics. Directly of course it has nothing to do with quantum mechanics. However, indirectly it does. General relativity can be expressed as a series, where the lowest term is Newtoniania, the first post-Newtonian term is a static correction, the next is similar to Maxwell's equations and so forth. Now for quantum field theory there is also a set of corrections. Two gravitons interacting have an O(1), which is classical, then an O(hbar) term and other higher order up to O(hbar^n) for n large. This perturbation sequence only makes sense in the long run if it converges to a nonperturbative theory, which is string theory or M-theory.The gamma here is predicted from the static gravity field of a star. If gamma = 1 exactly then we know that the above stuff converges properly to something which makes sense. This test with observing radio data from dstant quasars lensed by the solar gravity field puts gamma as unity to four orders of magnitude.LC This is a test of general relativity and on the outset it appears to have nothing to do with quantum mechanics. Directly of course it has nothing to do with quantum mechanics. However, indirectly it does. General relativity can be expressed as a series, where the lowest term is Newtoniania, the first post-Newtonian term is a static correction, the next is similar to Maxwell's equations and so forth. Now for quantum field theory there is also a set of corrections. Two gravitons interacting have an O(1), which is classical, then an O(hbar) term and other higher order up to O(hbar^n) for n large. This perturbation sequence only makes sense in the long run if it converges to a nonperturbative theory, which is string theory or M-theory.

The gamma here is predicted from the static gravity field of a star. If gamma = 1 exactly then we know that the above stuff converges properly to something which makes sense. This test with observing radio data from dstant quasars lensed by the solar gravity field puts gamma as unity to four orders of magnitude.

LC

]]> By: Astrofiendhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70307 Astrofiend Wed, 02 Sep 2009 09:30:07 +0000 http://www.universetoday.com/?p=38858#comment-70307 Is that the sound I hear of Einstein's monumentally beautiful theory being borne out yet again? I've been keeping an extremely accurate running tally of the triumphs of the general theory of relativity, vs. the likes of hokey EU-based pseudoscience. The results of this admittedly awesome study are as follows:Einstein: 12409783517123Crayon Physics: 0Science saves the day again. Hurrah! Is that the sound I hear of Einstein's monumentally beautiful theory being borne out yet again? I've been keeping an extremely accurate running tally of the triumphs of the general theory of relativity, vs. the likes of hokey EU-based pseudoscience. The results of this admittedly awesome study are as follows:

Einstein: 12409783517123

Crayon Physics: 0

Science saves the day again. Hurrah!

]]> By: NDhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70306 ND Wed, 02 Sep 2009 03:51:39 +0000 http://www.universetoday.com/?p=38858#comment-70306 I just reread this and they mention using Cassini to get a factor of 4. Is this to use Cassini as another receiver as part of the VLBA? I just reread this and they mention using Cassini to get a factor of 4. Is this to use Cassini as another receiver as part of the VLBA?

]]> By: NDhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70305 ND Wed, 02 Sep 2009 03:48:52 +0000 http://www.universetoday.com/?p=38858#comment-70305 To get the 1-in-1million precision, do we need a baseline that's larger than Earth? To get the 1-in-1million precision, do we need a baseline that's larger than Earth?

]]> By: NDhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70304 ND Wed, 02 Sep 2009 03:22:09 +0000 http://www.universetoday.com/?p=38858#comment-70304 Nephish777,http://www.scientificamerican.com/article.cfm?id=did-researchers-cook-data-from-first-general-relativity-test#comments Nephish777,

http://www.scientificamerican.com/article.cfm?id=did-researchers-cook-data-from-first-general-relativity-test#comments

]]> By: Nephish777http://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70302 Nephish777 Wed, 02 Sep 2009 01:54:41 +0000 http://www.universetoday.com/?p=38858#comment-70302 I understand there is doubt that the position shift in stars near the sun may no have been seen in 1919, but was for sure in a later eclipse. I understand there is doubt that the position shift in stars near the sun may no have been seen in 1919, but was for sure in a later eclipse.

]]> By: Yoohttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70301 Yoo Wed, 02 Sep 2009 01:40:11 +0000 http://www.universetoday.com/?p=38858#comment-70301 This is just a more precise verification of general relativity (which is interesting in its own right, but you know what I mean): how is this directly related to unifying general relativity and quantum theory? Albeit it would place restrictions on any unified theory, but when a headline mentions unification, I would have expected something else as well. This is just a more precise verification of general relativity (which is interesting in its own right, but you know what I mean): how is this directly related to unifying general relativity and quantum theory? Albeit it would place restrictions on any unified theory, but when a headline mentions unification, I would have expected something else as well.

]]> By: Lawrence B. Crowellhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70300 Lawrence B. Crowell Wed, 02 Sep 2009 00:26:26 +0000 http://www.universetoday.com/?p=38858#comment-70300 This is an interesting test of parameterized post Newtonian theory. The results are encouraging.LC This is an interesting test of parameterized post Newtonian theory. The results are encouraging.

LC

]]> By: IVAN3MANhttp://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70299 IVAN3MAN Wed, 02 Sep 2009 00:21:58 +0000 http://www.universetoday.com/?p=38858#comment-70299 Excellent article, Nancy!William928: <blockquote>Is that a snake I hear hissing?</blockquote> We are going to need <a href="http://www.pestproducts.com/snaketrap.htm" rel="nofollow"><b>this</b></a>. Excellent article, Nancy!

William928:

Is that a snake I hear hissing?

We are going to need this.

]]> By: William928http://www.universetoday.com/2009/09/01/new-way-to-measure-curvature-of-space-could-unite-gravity-theory/comment-page-1/#comment-70298 William928 Tue, 01 Sep 2009 23:15:43 +0000 http://www.universetoday.com/?p=38858#comment-70298 Oh Boy, Nancy, you've opened up a can of worms with this article. Is that a snake I hear hissing? Oh Boy, Nancy, you've opened up a can of worms with this article. Is that a snake I hear hissing?

]]>