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Physicist Claims Time Has a Geometry
sciencenews writes to tell us that a physicist at Stanford has just recently published a peer review website for several physics lectures focusing on a single underlying idea that "time is not a single dimension of spacetime but rather a local geometric distinction in spacetime." The science is presented quite clearly and originally uses GPS systems as a point of focus. From the article: "Not too long ago, people thought the Earth was flat, which meant they thought that gravity pointed in the same direction everywhere. Today, we think of that as a silly idea, but at the same time, most people today (including most scientists) still think of spacetime as if it were a big box with 3 space dimensions and 1 time dimension. So, like gravity for a flat Earth, the single time dimension for the 'big box universe' points in one direction, from the Big-Bang into the future. A lot of lip service is given to the idea of "curved spacetime", but the simplistic 3+1 'box' remains the dominant concept of what cosmic spacetime is like."
I always knew my high school geometry teacher came from another dimension.
I agree that there aren't a lot of people who intuitively reach to the Lorentz transform to explain the progression of time, but there are plenty of obvious reasons for that. Not sure it takes a Stanford physics prof. to make what is essentially a epistemological point though.
For kicks, check out one way to visualize the spacetime wheel.
http://tinyurl.com/4ny52
Perhaps someone should tell him that general relativity has already been invented. Physicists know that time has geometry---it is, after all, a part of spacetime, which has geometry. With regard to his claim that GPS has unexplained anomalies, he may be right. However, GPS is based on the Schwarzschild metric, which assumes a non-spinning, point-like mass. The earth is neither of these. Accordingly, there will be small corrections due to the combined effect of earth's spin and its density profile. At present, we are unable to calculate those corrections (we've only solved some important special cases, because the math is so hard), but they almost certainly explain the GPS deviations.
If time has many dimensions then I wonder why we perceive it to go forward only (though at different relative rates depending on relative speed). The reason why we perceived gravity to point down only was just a matter of not being able to see the big picture, although I would have thought more people would have noticed the Earth is round sooner, the curve is clearly visible from most mountaintops. So what's the big picture we need to see in order to see more dimensions to time? How do we step back and notice the slight curve in the horizon?
It sure seems like time goes forward only, from my own day to day observations. My mind can't even comprehend what going another direction (except for "backwards") would even mean as a concept.
"Time is an illusion. Lunchtime, doubly so."
In my experience, scientists who work with such issues are quite clear on this point (and, so far as I can tell, have been for eighty some years).
But for other sorts of scientists (e.g. biologists), engineers, and the rest of us, who only need to calculate things to five or ten decimal places or so, assuming that the time points in the same direction throughout the area of interest (and generally that space is flat and such) is reasonable--so reasonable, in fact, that we'd be nuts not to work with that as an assumption.
If I'm tracking the migration of some sort of beetle or planning a system of trusses to support a load or deciding if I should walk or drive to the store for milk, I would have to be mad to start out treating spacetime as a fine-grained network of plank-scale events with information flow between them determining the local geometry of space time (and thus the direction of time). Likewise with the effects of nearby astronomical bodies--if they were big enough and close enough to seriously distort spacetime I'd have a lot bigger problems to worry about. On average, to the level I'd ever need to deal with in these sorts of cases, it is now and the future is coming up later and the past is what already happened.
--MarkusQ
"Not too long ago, people thought the Earth was flat" It's a common misconception and almost modern myth that people in the recent past believed the earth was flat. The truth is that it was generally accepted by most learned people that the earth was spherical from the 1st century onwards and many argued so much earlier. You can read more about this here: http://en.wikipedia.org/wiki/Flat_earth
http://www.bede.org.uk/flatearth.htm -- This is one myth that really needs to die! Even more so than that Betsy Ross was involved with the American Flag.
There is definitely a good case to be made that the past-versus-future arrow of time is not fundamental. Basically our psychological sense that the past is different from the future comes from the direction of the thermodynamic arrow of time, but the second law of thermodynamics doesn't come from the basic laws of physics (which are essentially time-reversal symmetric) but from the boundary conditions of the universe: for some reason unknown to us, we had a low-entropy big bang. The meaning of "past" is really "that way to the big bang."
It's also probably true that in a complete theory of quantum gravity, the picture of three space dimensions plus one time dimension (3+1) would break down completely at small scales. The whole idea of distance and dimensionality is probably a large-scale approximation that loses its validity at small scales. There is a strong argument to be made that for fundamental reasons, spacetime must be discrete, not continuous, at the Planck scale. The only people seriously trying to construct discrete theories of quantum gravity right now seem to be the people doing loop quantum gravity (not string theory, which uses a flat 3+1 background of spacetime). For a good popular-level account of this kind of stuff, see Smolen's Three Roads to Quantum Gravity. In loop quantum gravity, they are able to construct an infinite set of possible universes (each one is a type of knot), but the problem is that none of them can be proved to resemble flat 3+1 spacetime, even asymptotically. In other words, there's no way you can even take this tangle of events and figure out whether it has anything like time and space that you can define on it. It's like being a flea living in a world that consists of threads woven together. On your scale, can't be sure whether it's a one-dimensional piece of yarn, a two-dimensional piece of fabric, or a three-dimensional wad of wool.
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Spacetime perceives time as a one dimensional vector that is orthogonal to all other vectors. Because relativistic equations for time, distance, mass, etc, use a sqare root function, you get imaginary distances and imaginary time when an object exceeds C. Usually, an imaginary quantity means that you're looking at the wrong axis.
(Trivial case in point: when solving a quadratic equation, if the parabola doesn't intersect the X axis, you will get a complex number. If you break that down into real and imaginary components, the imaginary components correspond to the displacement in the Y axis for that solution's real component value in the X axis.)
Ergo, if a tachyon exists, it would experience a spacial axis as "time" and the time axis as space, UNLESS "time" is not a single axis, in which case all bets are off.
In consequence of not having a telephone-number IQ, I can only speculate wildly, but I'm going to guess that the relativistic equations do indeed refer to some measure of bleeding between space and time and that no further dimensions are required - for GPS or for any other phenomena governed by relativity. (Superstrings being about the only exception I can think of.)
I personally think that part of the problem is that time IS regarded as "special", whereas perhaps it would be better if it were regarded as special "only as far as absolutely necessary". To the extent that specialness is an extra parameter, you want to eliminate all extra parameters as far as possible (and no further).
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
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Jump to page 25 of the second set of slides, where the author shows two time vectors at an angle to each other. If you have two observers, one with each time vector, then each observer thinks that the other is slowed down. Each sees redshifted light from the other.
This angle between time vectors can be caused by gravity or by the curvature of the universe.
In the gravity case, it is used to explain discrepancies in all sorts of measurements, from the Pioneer spacecraft, to the changes in the orbits of various celestial bodies, to discrepancies in the GPS, to the apparency that a U.S. atomic clock and a French one will each think the other is ticking slower. This is what most of the first slide show is about.
In the cosmological case, the idea is that the universe is round (see page 28 of the second presentation) and that the redshift that we think is due to the expansion of the unverse is actually due to the curvature of the universe, i.e., a galaxy around the universe from us will appear to have slower time, because its time vector is going in a different direction than ours. A galaxy ninety degrees around would appear to have time completely stopped, so it would be invisible to us (frequency of zero). Galaxies further away than that would be going backwards in time from our perspective, but we can't see them.
This is an idea I have not seen before. It seems really neat to me. It seems plausible but then (a) I can't personally verify the observations that he claims validate his theory; he could have produced fake graphs and they would fool me, but I would think it would be easy for him to get caught at that, and (b) even though I've had calculus up to differential equations, I never had non-Euclidean geometry or higher-dimensional stuff, so I can't actually follow his calculations very well. Then again, I didn't try very hard.
We shall soon see if he has made a significant error. The numbers and the observations will tell the story; either they work out, or they don't.
Sunlit World Scheme. Weird and different.
that the Timecube is *not* a Flying Spaghetti Monster. Most likely, Timecube is the 4th dimensional manifestation of FSM (or other way around. I wonder if hyperstring ... eh, hyperspaghetti theory has to do with it)
"Einstein's relativity theory still remains a THEORY, seeing as how no one has actually tested the limits of it."
What has testing got to do with it? It will always be a theory, because that's all science can produce. If you want something definate you want mathematical theorems - those are known to be true. Theories never will be - they can just be very reliable at predicting things, nothing more.
Math theorems don't necessarily have to apply to the physical universe. The axioms on which the theorems are built are explicitly part of the theorems, leading to a logically self-consistent system. That is, you define the particular 'universe' you want to study by setting down axioms, then you prove things which you know are true about that universe because you've derived them in a logical fashion from those axioms you've set down.
What is this 'reality' you speak of?
Mathematics isn't constrained by our perceptions of what it 'should' be or what feels right. It's constrained by the axioms and principles we build it from. And in this case, 0.9 recurring is exactly equal to one. As you demonstrated, there are countless proofs of it (the one you selected being one of the less rigorous ones), and since the proofs are not incorrect, it means that their conclusion is wholly true, from a mathematical point of view.
Please stop harping about Lorenz and time.
In his paper "On the Cause of Geodetic Satellite Accelerations and Other Correlated Unmodeled Phenomena", via the American Geophysical Union in December 2005, he outlined specific modifications to general relativity. The paper's Abstract begins:
"An oversight in the development of the Einstein field equations requires a well-defined amendment to general relativity that very slightly modifies the weak-field Schwarzschild geometry yielding unambiguous new predictions of gravitational relativistic phenomena."
The result of this amendment is an additional relativistic effect. As you may know, in general relativity, the velocity of light is a constant. Thus one's velocity relative to a photon can result in a shift of measured frequency, i.e. the red-shift, or blue-shift of spectra. Also, since the theory claims that accelerated reference frames are identical, this shift is also observed due to gravitational acceleration.
The author claims that gravitationally induced red-shifting is also dependent on the angle through which a photon travels in a gravitational field. In addition, the theory discusses gravity and angular momentum. An accelerating electric charge emits electromagnetic energy. Though long theorized, a similar gravity wave has never been observed. The author suggests that angular momentum, e.g. spinning and orbiting masses emit electromagnetic energy as well. Thus, orbits even in a perfect vacuum will decay. As a spinning body slows, or orbital momentum decays, this energy will be balanced by radiation in the microwave range.
The additional source relativistic red shift, and the additional changes with respect to conservation of momentum, have profound cosmological import, if true. The theory passes the simplicity and beauty tests admirably. What I particularly like about his presentation has to do with testability.
He discusses numerous problems with the GPS and geodetic satellite systems, various puzzling data from several deep space missions, the orbits of planets and moons, and show how his equations account for the discrepancies in the data. He also proposes a number of simple experiments which could prove or disprove his theory. He predicts what to look for in terrestrial microwave radiation, and suggests experiments that could be run using existing satellites which could prove or disprove his theory. He also suggest that other scientist look at data which has already been collected but which he has never seen, and predicts what patterns might confirm the theory.
From the ground up, the ideas are well reasoned, and his approach seems scientifically sound.
Time gets into the mix, because the broader ramifications of the theory are large. Imagine a space ship under constant acceleration. On the floor (aft bulkhead) place two clocks communicating via pulses of light. He shows how each clock (even though they share the same acceleration reference frame) will each view the other as slow. By virtue of general relativity, pairs of clocks on earth should likewise each view the ticks of another clock as slow. Thus, there is no common, universal time. The rate of time is a local attribute at each location.
The cosmological implications if this theory are also impressive.
There is no need to posit dark matter or dark energy. They are discussed only to account for missing matter and the expansion of the universe. However, if this theory is true, the universe is not expanding, thus removing the need to postulate dark energy. The matter needed to keep galaxies from flying apart is no longer needed. Rotating galaxies are radiating microwaves and slowing down, not being gripped by dark matter. The universe finite and unbounded. It is neither expanding nor contracting.
No big bang would have happened. Remember the history of the theory? It was attempting to account for red shifted stellar spectra and for the microwave background. If the red shift is a relativistic phenomenon (not the result of unive
Given that caveat, I found Mayer worth a serious look. He's got a number of references showing measurements that GR does not explain. The most convincing stuff is from GPS satellite measurements which show an unexplained sawtooth pattern with a period of two cycles per day and an amplitude of several feet (or nanoseconds). GPS satellites and ground stations explicitly correct for the general relativistic effects of the earth's gravity well, so any anomalies would be very interesting. But he's also got anomalies in measurements of hydrogen 21 cm radiation and in the effect of Ganymede on signals sent from the Galileo spacecraft.
If Mayer faked the anomalies (but I believe they're real), he would be shot down in no time. Assuming the anomalies are real, then any theory that can explain them in addition to the rest of the effects explained by GR (precession of Mercury's orbit, redshift of a gravity well, etc) deserves a serious look.
One other point. In grad school, when we students complained about the many annoyances involved in writing and publishing our work, my advisor would say "50% of science is communication." There's alot of wisdom in that. There are plenty of cranks (or not so cranky folk) out there tugging on physicists' sleeves and saying "Einstein was wrong and I have a notebook full of equations to prove it!" I know such a fellow myself, but it would take weeks to examine his equations and maybe months to explain his errors. What he and his ilk lack is the ability to communicate like a scientist. Anyway, where I'm going with all this is that Mayer suffers no such lack. His 'Lecture 1' document is much better than average writing by a scientist. While this doesn't prove his equations are better than Einstein's, it is further reason why he deserves a serious look.
--- Often in error; never in doubt!