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Loop Gravity and the Bouncing Universe
My fellow cosmologists, the October issue of the Scientific American
has a very good article on a new theory of quantum gravity, Loop Gravity, which is very interesting. It talks about theoretical "atoms" of space-time that are little spheres the diameter a Planck- length. These atoms of space-time can only hold so much energy, and then their gravity turns repulsive. So point singularities can never form, and a collapsing universe will never reach a singularity, but will only reach a state of extreme density, at which time the repulsive gravity will make it bounce back in an apparent Big Bang. The model shows that little information could come through this big crunch because of quantum scrambling. The theory predicts that different frequencies of light may travel at slightly different speeds! (Haven't I been saying that?) Anyway, it's a good read and worth pondering. Any thoery that gets rid of singularities is a step forward. You can also read it at http://www.sciam.com/article.cfm?id=...-or-big-bounce Double-A |
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Loop Gravity and the Bouncing Universe
On Oct 15, 12:13 pm, Double-A wrote:
My fellow cosmologists, the October issue of the Scientific American has a very good article on a new theory of quantum gravity, Loop Gravity, which is very interesting. It talks about theoretical "atoms" of space-time that are little spheres the diameter a Planck- length. These atoms of space-time can only hold so much energy, and then their gravity turns repulsive. So point singularities can never form, and a collapsing universe will never reach a singularity, but will only reach a state of extreme density, at which time the repulsive gravity will make it bounce back in an apparent Big Bang. The model shows that little information could come through this big crunch because of quantum scrambling. The theory predicts that different frequencies of light may travel at slightly different speeds! (Haven't I been saying that?) Anyway, it's a good read and worth pondering. Any thoery that gets rid of singularities is a step forward. You can also read it at http://www.sciam.com/article.cfm?id=...-or-big-bounce Interesting piece, AA. It's actually a refined variation of the oscillating/reciprocating and 'eternal return' models. And it's interesting that the author speaks of "space-time atoms", which would be a rough corollary to our sub-Planckian 'granulons' comprizing the SPED. However, the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. Then juxtapose this model alongside the CBB model which recognizes two distinct referance frames : the restricted 'inside' frame which perceives only a singular 'Bang' bouncing back from a singular 'crunch' (like a single power stroke of a piston). Then there's the overarching 'outside' frame from whence the whole Process is seen continuously running, like a gas turbine. http://community-2.webtv.net/oldcoot/ContinuousBigBang/ This is why the CBB model subsumes but *does not negate* the singular BigBang (or singular Big Bounce) idea. Hell, there's even a (singular) Big Bloom idea floating around the web. :-) |
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Loop Gravity and the Bouncing Universe
"oldcoot" wrote in message...
... On Oct 15, 12:13 pm, Double-A wrote: My fellow cosmologists, the October issue of the Scientific American has a very good article on a new theory of quantum gravity, Loop Gravity, which is very interesting. It talks about theoretical "atoms" of space-time that are little spheres the diameter a Planck- length. These atoms of space-time can only hold so much energy, and then their gravity turns repulsive. So point singularities can never form, and a collapsing universe will never reach a singularity, but will only reach a state of extreme density, at which time the repulsive gravity will make it bounce back in an apparent Big Bang. The model shows that little information could come through this big crunch because of quantum scrambling. The theory predicts that different frequencies of light may travel at slightly different speeds! (Haven't I been saying that?) Anyway, it's a good read and worth pondering. Any thoery that gets rid of singularities is a step forward. You can also read it at http://www.sciam.com/article.cfm?id=...-or-big-bounce Interesting piece, AA. It's actually a refined variation of the oscillating/reciprocating and 'eternal return' models. And it's interesting that the author speaks of "space-time atoms", which would be a rough corollary to our sub-Planckian 'granulons' comprizing the SPED. However, the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. Then juxtapose this model alongside the CBB model which recognizes two distinct referance frames : the restricted 'inside' frame which perceives only a singular 'Bang' bouncing back from a singular 'crunch' (like a single power stroke of a piston). Then there's the overarching 'outside' frame from whence the whole Process is seen continuously running, like a gas turbine. http://community-2.webtv.net/oldcoot/ContinuousBigBang/ This is why the CBB model subsumes but *does not negate* the singular BigBang (or singular Big Bounce) idea. Hell, there's even a (singular) Big Bloom idea floating around the web. :-) So if LQG ever takes off as the Primo, Mainstream "Quantum Theory of Gravity", you could always change the name of Wolter's to "Continuous Big BOUNCE" and still keep the same initials! ("CB BLOOM" wouldn't do because it's inconsistent with LQG.) LQG's been around for awhile, BTW, starting back in '86. SA is really reaching when it publishes a story on quantum gravity. I love it. I still get SA here at the house every month. happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S. "Prediction is very difficult, especially about the future." Niels Bohr P.P.S.: http://yummycake.secretsgolden.com http://garden-of-ebooks.blogspot.com http://painellsworth.net |
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Loop Gravity and the Bouncing Universe
On Oct 15, 9:03*pm, oldcoot wrote:
On Oct 15, 12:13 pm, Double-A wrote: My fellow cosmologists, the October issue of the Scientific American has a very good article on a new theory of quantum gravity, Loop Gravity, which is very interesting. *It talks about theoretical "atoms" of space-time that are little spheres the diameter a Planck- length. *These atoms of space-time can only hold so much energy, and then their gravity turns repulsive. *So point singularities can never form, and a collapsing universe will never reach a singularity, but will only reach a state of extreme density, at which time the repulsive gravity will make it bounce back in an apparent Big Bang. The model shows that little information could come through this big crunch because of quantum scrambling. *The theory predicts that different frequencies of light may travel at slightly different speeds! *(Haven't I been saying that?) *Anyway, it's a good read and worth pondering. *Any thoery that gets rid of singularities is a step forward. *You can also read it at http://www.sciam.com/article.cfm?id=...-or-big-bounce Interesting piece, AA. It's actually a refined variation of the oscillating/reciprocating and 'eternal return' models. And it's interesting that the author speaks of "space-time atoms", which would be a rough corollary to our sub-Planckian 'granulons' comprizing the SPED. Right. However, the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. This doesn't sound like void space to me. Also its talking about photons interacting with the space-time atoms doesn't sound like void space. * * * * * * * * * * * Then juxtapose this model alongside the CBB model which recognizes two distinct referance frames : the restricted 'inside' frame which perceives only a singular 'Bang' bouncing back from a singular 'crunch' (like a single power stroke of a *piston). Then there's the overarching 'outside' frame from whence the whole Process is seen continuously running, like a gas turbine.http://community-2.webtv.net/oldcoot/ContinuousBigBang/ This is why the CBB model subsumes but *does not negate* the singular BigBang (or singular Big Bounce) idea. Hell, there's even a (singular) Big Bloom idea floating around the web. * I really like the way it theorizes a big crunch and bang while avoiding a singularity. Double-A |
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Loop Gravity and the Bouncing Universe
On Oct 16, 12:12*pm, Double-A wrote:
oldcoot wrote: ...the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. This doesn't sound like void space to me. *Also its talking about photons interacting with the space-time atoms doesn't sound like void space. When Uncle Albert kicked out the "aether", he had to substitute something for it. The mathematical abstraction "space-time" became its surrogate. That way, space could still be an abstract 'something' while abiding by the mandate that there is "no medium". So when somebody talks about "space-time atoms", this same edict is adhered to. It forbits existance of a literal spatial medium, either the archaic "aether" or the SPED. ...the CBB model subsumes but *does not negate* the singular BigBang (or singular Big Bounce) idea. Hell, there's even a (singular) Big Bloom idea floating around the web. * I really like the way it theorizes a big crunch and bang while avoiding a singularity. Actually it postulates a 'squashed out', spinning disc similar to the 'ring singularity' of the Kerr BH model. |
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Loop Gravity and the Bouncing Universe
On Oct 16, 12:41*pm, oldcoot wrote:
On Oct 16, 12:12*pm, Double-A wrote: oldcoot wrote: ...the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. This doesn't sound like void space to me. *Also its talking about photons interacting with the space-time atoms doesn't sound like void space. When Uncle Albert kicked out the "aether", he had to substitute something for it. The mathematical abstraction "space-time" became its surrogate. That way, space could still be an abstract 'something' while abiding by the mandate that there is "no medium". So when somebody talks about "space-time atoms", this same edict is adhered to. It forbits existance of a literal spatial medium, either the archaic "aether" or the SPED. Einstein's only objection to the classical aether was that it couldn't be used as a rest frame against which to mesure absolute motion. (The quote is out there if only I had time to find it.) By theorizing space-time atoms, it would seem to me they would have some local existence, if they interact with photons, and contain defferent amounts of energt depending on location. I don't see how he can do this without by doing so establishing an absolute rest frame. If space has atoms, then the objects in space would have velocities relative to any particlular space-time atom. The author holds to relativity, but if he is establishing an abolute reference frame by defining these atoms, then relativity will go out the window! ...the CBB model subsumes but *does not negate* the singular BigBang (or singular Big Bounce) idea. Hell, there's even a (singular) Big Bloom idea floating around the web. * I really like the way it theorizes a big crunch and bang while avoiding a singularity. Actually it postulates a 'squashed out', spinning disc similar to the 'ring singularity' of the Kerr BH model. So I guess "spin is in"! (I couldn't resist.) Double-A |
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Loop Gravity and the Bouncing Universe
"Double-A" wrote in message...
... On Oct 16, 12:41 pm, oldcoot wrote: On Oct 16, 12:12 pm, Double-A wrote: oldcoot wrote: ...the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. This doesn't sound like void space to me. Also its talking about photons interacting with the space-time atoms doesn't sound like void space. When Uncle Albert kicked out the "aether", he had to substitute something for it. The mathematical abstraction "space-time" became its surrogate. That way, space could still be an abstract 'something' while abiding by the mandate that there is "no medium". So when somebody talks about "space-time atoms", this same edict is adhered to. It forbits existance of a literal spatial medium, either the archaic "aether" or the SPED. Einstein's only objection to the classical aether was that it couldn't be used as a rest frame against which to mesure absolute motion. (The quote is out there if only I had time to find it.) . . . Double-A Here's the only "sourced" quote i could find... "We may assume the existence of an aether; only we must give up ascribing a definite state of motion to it, i.e. we must by abstraction take from it the last mechanical characteristic which Lorentz had still left it." Source: On the irrelevance of the luminiferous aether hypothesis to physical measurements, in an address at the University of Leiden (May 5, 1920) happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S. (to a young physics student) "Your theory is crazy, but it's not crazy enough to be true." Niels Bohr P.P.S.: http://yummycake.secretsgolden.com http://garden-of-ebooks.blogspot.com http://painellsworth.net |
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Loop Gravity and the Bouncing Universe
On Oct 17, 4:30*pm, "Painius" wrote:
"Double-A" wrote in message... ... On Oct 16, 12:41 pm, oldcoot wrote: On Oct 16, 12:12 pm, Double-A wrote: oldcoot wrote: ...the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. This doesn't sound like void space to me. Also its talking about photons interacting with the space-time atoms doesn't sound like void space. When Uncle Albert kicked out the "aether", he had to substitute something for it. The mathematical abstraction "space-time" became its surrogate. That way, space could still be an abstract 'something' while abiding by the mandate that there is "no medium". So when somebody talks about "space-time atoms", this same edict is adhered to. It forbits existance of a literal spatial medium, either the archaic "aether" or the SPED. Einstein's only objection to the classical aether was that it couldn't be used as a rest frame against which to mesure absolute motion. *(The quote is out there if only I had time to find it.) . . . Double-A Here's the only "sourced" quote i could find... *"We may assume the existence of an aether; only we *must give up ascribing a definite state of motion to it, *i.e. we must by abstraction take from it the last *mechanical characteristic which Lorentz had still left it." *Source: *On the irrelevance of the luminiferous aether *hypothesis to physical measurements, in an address at *the University of Leiden (May 5, 1920) happy days and... * *starry starry nights! -- Indelibly yours, Paine Ellsworth Yes, that's the quote, and the final lines at the end: "But this ether may not be thought of as endowed with the quality characteristic of ponderable inedia, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it." http://www.tu-harburg.de/rzt/rzt/it/Ether.html The detection of the Earth's rotation by interferometer is called the Sagnac effect: "The first ring interferometry experiment aimed at observing the correlation of angular velocity and phase-shift was performed by the Frenchman Georges Sagnac in 1913, which is why the effect is named for him. Its purpose was to detect "the effect of the relative motion of the ether". An experiment conducted in 1911 by Francis Harress, aimed at making measurements of Fresnel drag of light propagating through moving glass, was later recognized as actually constituting a Sagnac experiment. Harress had ascribed the "unexpected bias" to something else. In 1926 a very ambitious ring interferometry experiment was set up by Albert Michelson and Henry Gale. The aim was to find out whether the rotation of the Earth has an effect on the propagation of light in the vicinity of the Earth. The Michelson-Gale experiment was a very large ring interferometer, (a perimeter of 1.9 kilometer), large enough to detect the angular velocity of the Earth. The outcome of the experiment was that the angular velocity of the Earth as measured by astronomy was confirmed to within measuring accuracy. The ring interferometer of the Michelson-Gale experiment was not calibrated by comparison with an outside reference (which was not possible, because the setup was fixed to the Earth). From its design it could be deduced where the central interference fringe ought to be if there would be zero shift. The measured shift was 230 parts in 1000, with an accuracy of 5 parts in 1000. The predicted shift was 237 parts in 1000." http://en.wikipedia.org/wiki/Sagnac_effect Double-A |
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Loop Gravity and the Bouncing Universe
"Double-A" wrote in message...
... On Oct 17, 4:30 pm, "Painius" wrote: "Double-A" wrote in message... ... On Oct 16, 12:41 pm, oldcoot wrote: On Oct 16, 12:12 pm, Double-A wrote: oldcoot wrote: ...the euphamism "space-time" is still mandated because the VSP forbids existance of the SPED. This doesn't sound like void space to me. Also its talking about photons interacting with the space-time atoms doesn't sound like void space. When Uncle Albert kicked out the "aether", he had to substitute something for it. The mathematical abstraction "space-time" became its surrogate. That way, space could still be an abstract 'something' while abiding by the mandate that there is "no medium". So when somebody talks about "space-time atoms", this same edict is adhered to. It forbits existance of a literal spatial medium, either the archaic "aether" or the SPED. Einstein's only objection to the classical aether was that it couldn't be used as a rest frame against which to mesure absolute motion. (The quote is out there if only I had time to find it.) . . . Here's the only "sourced" quote i could find... "We may assume the existence of an aether; only we must give up ascribing a definite state of motion to it, i.e. we must by abstraction take from it the last mechanical characteristic which Lorentz had still left it." Source: On the irrelevance of the luminiferous aether hypothesis to physical measurements, in an address at the University of Leiden (May 5, 1920) Yes, that's the quote, and the final lines at the end: "But this ether may not be thought of as endowed with the quality characteristic of ponderable inedia, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it." http://www.tu-harburg.de/rzt/rzt/it/Ether.html The detection of the Earth's rotation by interferometer is called the Sagnac effect: "The first ring interferometry experiment aimed at observing the correlation of angular velocity and phase-shift was performed by the Frenchman Georges Sagnac in 1913, which is why the effect is named for him. Its purpose was to detect "the effect of the relative motion of the ether". An experiment conducted in 1911 by Francis Harress, aimed at making measurements of Fresnel drag of light propagating through moving glass, was later recognized as actually constituting a Sagnac experiment. Harress had ascribed the "unexpected bias" to something else. In 1926 a very ambitious ring interferometry experiment was set up by Albert Michelson and Henry Gale. The aim was to find out whether the rotation of the Earth has an effect on the propagation of light in the vicinity of the Earth. The Michelson-Gale experiment was a very large ring interferometer, (a perimeter of 1.9 kilometer), large enough to detect the angular velocity of the Earth. The outcome of the experiment was that the angular velocity of the Earth as measured by astronomy was confirmed to within measuring accuracy. The ring interferometer of the Michelson-Gale experiment was not calibrated by comparison with an outside reference (which was not possible, because the setup was fixed to the Earth). From its design it could be deduced where the central interference fringe ought to be if there would be zero shift. The measured shift was 230 parts in 1000, with an accuracy of 5 parts in 1000. The predicted shift was 237 parts in 1000." http://en.wikipedia.org/wiki/Sagnac_effect Double-A I don't understand. As a practical thing, the Sagnac effect appears to be very useful. But the article didn't seem to say whether or not Sagnac's effort to detect "the effect of the relative motion of the ether" was considered a success by his peers. Apparently, judging by an ensuing droppage of any "ether", Sagnac's theoretical goal was not believed to have been reached? There is also no description of Michelson's conclusions he drew from his and Gale's experiment. Did he and Gale think that the ring interferometer was as ineffective as the interferometer he used in his experiment with Morley? (I.e., ineffective as to showing the existence of an ether?) happy days and... starry starry nights! -- Indelibly yours, Paine Ellsworth P.S. (to a young physics student) "Your theory is crazy, but it's not crazy enough to be true." Niels Bohr P.P.S.: http://yummycake.secretsgolden.com http://garden-of-ebooks.blogspot.com http://painellsworth.net |
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Loop Gravity and the Bouncing Universe
Double A Your post has me begging this question What is absolute
motion? TreBert |
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