Catch up on stories from the past week (and beyond) at the Slashdot story archive


Forgot your password?
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×

Comment M-Theory for morons (Score 1) 332

Here is the easy message: it is not a theory - a way to do many calculations, all confirmed by experimental tests. People who work on M-Theory hope it becomes a theory some day. Even us folks on the ultra-conservative fringe of physics ( would not publish such silliness.

Be a real man, woman, or pre-op tranny and buy the "No Stinkin Higgs" t-shirt ( that predicts, well, that they will not find the Higgs or some time-traveling singlet.


Comment Re:high enough energy? (Score 1) 196

Wow! Thanks for the detailed technical reply. I read it twice and have bookmarked it. Grounded skepticism, nice.

Let's see if I can subtract away a bit of the jargon, to abstract the first two problems, so they sound similar. The horizon problem is that all parts of the Universe are traveling at the same speed, but they would always be too far apart from each other to reach an agreement on the speed. Let's call that the constant velocity problem instead. Everyone happens to be traveling at the same speed. Why they reach that particular speed is not known. Constant velocity problems happen in many physics problems.

The flatness problem is about the stability of the solution. Let's call it that then, the stability problem.

What the big bang needs is a stable, constant velocity solution that uses the force of gravity. So far, nothing accomplished, just a word game.

For the dark matter issue, I will focus on a smaller set of issues, just the rotation profile of thin disk galaxies. I don't read many papers in the technical literature, but did find one by Alar Toomre in the 1960s who figured out how to apply good old Newton's law to a disk galaxy. It is not trivial, and I really didn't understand how he applied elliptical integrals to solve the problem. Two things I do recall. First was that the solution was unstable. If a disk galaxy gets a slight nudge along the axis, it should curl up into a ball. It is not unusual to see one galaxy pass close to another (I think that is happening to the Milky Way), but the galaxies appear to be stable. Let's call this the stability problem.

Apply Newton's law to these galaxies, and you can get the velocities right as long as you stay near the core to the max velocity. It is out on the edge were problems live. Even where the stars don't shine, gas has been spotted going at the same darn speed. Everyone wants to go at the same constant velocity.

What the rotation profile of thin disk galaxies needs is a stable, constant velocity solution that uses the force of gravity. This is again a word game, it also does not cover the variety of cases seen for dark matter, but it is fun to construct a link based on reasonable abstraction of the problem descriptions (others may judge if I have been reasonable).

I do have a physics speculation for a stable, constant velocity solution that uses the force of gravity. Before I get there, I will define precisely what I mean by a physics speculation.
1. It must be a specific equation
2. It must be consistent with all partially successful earlier speculations

Apply this precise definition of a physics speculation to gravity. One could call Newton's law of gravity a speculation. It was the first, so didn't have any companions. It kept collecting more and more data to support it. About the only problem was a minor precession of the perihelion of Mercury. Jupiter all ready contributed 10x this amount.

Einstein spotted the problem with Newton's law soon after formulating special relativity: nothing travels faster than the speed of light, not even gravity. It took ten years to develop the field equations, then Schwarzschild found a solution, so that Einstein could then solve this small problem (he was giddy about this result for three days). The depth of the mathematical rewrite is stunning, but there is a way to pluck out Newton's law from Einstein's speculations. Those too have been confirmed for weak and strong fields.

As discussed above, Newton's law fails for the rotation profile of thin disk galaxies. Why not use Einstein's better law? It has been quantified how much that kind of shift would make for these low density, slow moving objects. This is the region where Newton does well in our planetary system, but fails for big stuff.

Is this a BIG failure? If you read technical literature or any popularization, they will trumpet the idea that this is beyond huge, super massive, because everyone describes it that way. Can you give me a ball park estimate on how strong gravity is for the gas rotating around a disk galaxy with a hundred billion or more stars inside it? Compare it to good old familiar g on the Earth. If you do the calculation, gravity in the outer reaches of a galaxy is at least ten orders of magnitude smaller than gravity on puny Earth. This is a small problem.

Milgrom has also provided a speculation, that when gravity gets weak enough (>10^-8g?), it flips from a 1/R^2 force law to 1/R (I believe he dislikes when his work is described in such ways, but I covet a concise mathematical abstraction). For hundreds of disk galaxies, that speculation works. I am not enough of a student of MOND to list all its successes. As you noted, MOND has taken a bullet galaxy to the head. We have been able to spot one bullet galaxy passing through another galaxy, mapped where the gravitational center is, and mapped the matter based on light, and measured that they were not in the same place. With MOND, the gravitational potential should be right atop the visible matter. I don't see a way around that either.

Any further speculations must be consistent with Milgrom's math observation that has worked well repeatedly. The Swiss school teacher Balmer may have guessed his formula for hydrogen spectral lines, but Bohr's quantization of angular momentum had to get along with it.

My definition of a physics speculation is not satisfied by work being done with dark matter. People programming get to test different model distributions until the grant money dries up. Start with the sphere, refine with an ellipse, try out something flat, feel free to do what you want. Since they are stuffing the ballot box in the mass term, they are not showing due respect for MOND's success with the R term.

I have a physics speculation that fits my definition. The label was in my previous post: relativistic rocket science. MOND and dark matter change the cause of gravity, either the distance dependence or the source mass. The other side of the equation is the effect of gravity, a change in momentum, mass times velocity. By the product rule of calculus, one must consider the constant velocity times the change in velocity plus the constant velocity times the change in mass. The former is mass times acceleration, mA, the latter is the stuff of rocket science.

Current efforts use mass times acceleration exclusively. I have seen papers that did consider the change in mass term, but because the mass of a galaxy changes so slowly, it was determined to be irrelevant. That analysis sounds right: galaxies don't change much in time.

Galaxies do change as you move in space from the core out to the edge. How much mass there is in a disk depends on how far one is from the core. This is my relativistic rocket science equation:

- G M m/R^2 (R_hat + V_hat) = m dV/dt R_hat + v c dm/dR V_hat

The effect of gravity near the core is dominated by the usual mA term. Nothing about that term is altered. There is a new effect of gravity in a new direction. It is manifestly a constant velocity solution. That comes right out of the product rule. If the R_hat term is zero, then the constant velocity solution has an exponential solution. The first term of the Taylor series expansion is a 1/R term, respecting the success of MOND. The bullet galaxy to the head can be dodged because there are now two effects of gravity: one that deals with acceleration, and another where mass is in space.

I am not ashamed to say I have written a short equation that frightens me, that I don't think I will ever be able to solve (probably because it needs to be done numerically, another skill I lack). One cannot take galaxy modeling software off the shelf and test it because the little m plays a different role on the two sides of the equation. Rocket scientists have experience with that.

This physics speculation has one less parameter than MOND. I have shown this to a few physicists, and get the quick beat down, "what is that?" dismissal. I have never seen it before, it is in none of my physics books, the units are fine, it dictates mass distribution for stuff going at a constant velocity, it is simple yet not trivial, the rarest of birds in the aviary of ideas. I wish I could say, "shut up and calculate" but I wouldn't know who to say it to.

Data from the big bang says there was no mA, it was all relativistic rocket science, gravity directing where all the mass flies, all at the same speed to 5 significant digits. Quite the show it must have been. Can relativistic rocket science be Gaussian random and scale invariant? I don't know what those terms mean. Hopefully they are related to exponentials in some way since that is the no acceleration solution.

If the effect of gravity is a battle between mA in R_hat and relativistic rocket science in V_hat, it would not be a surprise if the balance of power shifted between the two as the Universe ages. Since the data from the big bang has committed to be 100% rocket science, later on more of the effect of gravity has to be acceleration. Until I wrote this reply, I had not connected that dot. Nice. I guess the time writing this post was well spent.


Comment Re:high enough energy? (Score 1) 196

As a cosmologist, how do you feel about rethought and reanalysis of 1. The particles that cause inflation, 2. Dark matter needed for various galaxies and clusters of galaxies, 3. Dark energy needed for the accelerating universe?

There are problems with the classic big bang model, with velocities seen in galaxies, and the acceleration of the galaxies. My money is that all of these are hard math problems, not a new type of matter. I even have a specific equation I would like to apply to these problems in particular, but I am not good enough at relativistic rocket science to give it a go.

I am with you on the no Higgs/no supersymmetry.

Comment Re:No Higgs, no super symmetry, but a t-shirt (Score 1) 196

Gravity is literally a universal love force: no matter what you are made of, everything else in the Universe wants to get closer to you (whether you have showed or not). We all want to rush to the center of the Earth - a fall that would take a little over 20 minutes - but are stuck in an atomic-level traffic jam. How can we make universal attraction a law? My proposal is that the rule for multiplying 4 numbers together does not have a single minus sign. Without a minus sign, repelling does not happen. That is the accounting secret. The all-positive product is the box-times symbols on the t-shirt, or hypercomplex numbers/Klein 4-group on wikipedia. Physicists use something known as tensor calculus, and that blocks a direct road to this kind of multiplication.

Comment Re:No Higgs, no super symmetry, but a t-shirt (Score 1) 196

A fine question. x is the "implied" multiplication. In C programming, you have to write A * B. In physics books, you write A B. So any implied multiplication uses quaternions, any box-times is hypercomplex.

The video is geared towards people who can do 1st year college calculus, or high school level if you are headed off to MIT.

Comment No Higgs, no super symmetry, but a t-shirt (Score 2) 196

That's my prediction, and my t-shirt:

The idea: Maxwell's field theory is the best one we have, the basis of the standard model by swapping out the gauge groups. I figured out how to write the Lagrange density (every way energy can be exchanged inside a box) using quaternions. That is not so hard. Do you know how to factor (B^2 - E^2)? If so, then (Del A - (Del A)*)(A Del - (A Del)*) is the same thing, quaternion style. The quaternions cannot do gravity which involves totally symmetric changes in a metric. Therefore I used an even less popular algebra known by names such as the hypercomplex numbers or the Klein 4-group. Put that into the Lagrangian, which flips exactly half the signs. That makes my proposal for gravity.

Combine the EM quaternion rewrite with the hypercomplex gravity Lagrangian, but without that -(Del A)* thing which was subtracting away the gauge term. The gauge term is there in both the gravity and EM portion, but they wipe out each other, so gravity and EM apply to massive particles, but overall the Lagrangian is gauge invariant. The Higgs mechanism works via a clever solution. My unified standard model works via a clever Lagragian.

By the end of 2012, I will know if my t-shirt is wrong because the Higgs and/or supersymmetric particles are found, or my t-shirt is barking near the right tree.

Supporting material about the t-shirt

Comment Hope not, or my unified SM theory is dead (Score 1) 271

Got my own theory where gravity and the symmetries of the standard model (U(1), SU(2), and SU(3)) live together in the Lagrange density. To make the Lagrangian gauge invariant, the difference between the part for gravity (which is not gauge invariant and thus applies to particles with mass) and the one for the other three (which is also no gauge invariant and thus dito) creates a Lagrangian that overall in gauge invariant. No Higgs particle needed, nor 5 Higgs particles.

You'll never see my work on the preprint server (wrong email address). You can buy it on a t-shirt, watch it on YouTube, or look at non-peer reviewed papers.

TheStandUpPhysicist the t-shirt Close as I can do to a paper Transformed paper into a Mathematica notebook to check the math The notebook as a pdf file
Lots of stuff on YouTube

Comment Re:time has no arrow, spacetime does (Score 1) 578

No, I am bringing up an accounting issue. There is no time without space, no space without time, so while it is good English to talk about time, it is bad mathematical physics. One is restricted to only talk about spacetime. We all experience changes in spacetime - we all get older in almost the same place in space.

In classical physics, for a collection of events in spacetime where changes in space are far less than changes in time (dR/dt < < c), events in spacetime are ordered by time, like a movie. In quantum physics, my own work with quaternions derivatives indicates that the reason things are "odd" is that for a different collection of events in spacetime, changes in space are greater than changes in time (dR/dt > > c). In the limit, changes in time go to zero before changes in space, so one loses the "movie-ness" of this set of events. One cannot say one event happened before another. There can be no causal link between any of the events in the quantum set. The events are too far apart to order in time. Instead, one can say there are a collection of possibilities and here are the odds of any particular thing happening. Doing 4D calculus correctly may explain the reason for the differences between classical and quantum physics.

Comment Quaternion spacetime reversal is local, not global (Score 2, Insightful) 578

For fun, let me be more technical.

If you want to reverse the time of a spacetime event, you use this member of the Lorentz group, diag{-1, 1, 1, 1}. Have that act on a 4-vector (t, x, y, z) and you get (-t, x, y, z). Now how are you going to get time back to were it started? Use exactly the same element. The Lorentz group is a global symmetry. It is to all levels of accuracy the same darn thing. Makes much math easier, but it is why physicists say the laws are identical if time goes backwards or forwards.

The important laws in physics are local. Both the standard model and general relativity depend on the values of t, x, y, z. Let's construct a local time reversal operator, call it B, such that B (t, x, y, z) = (-t, x, y, z). This can be done by presuming all three of these are quaternions, a 4D rank 1 tensor upgraded to also be able multiply and divide like real and complex numbers (full disclosure: I own R can be calculated, it is (x^2 + y^2 + z^2 - t^2, 2 t x, 2 t y, 2 t z)/(t^2 + x^2 + y^2 + z^2). That will work every time, but if you want to reverse something, then reverse it again, the second B will not be identical to the first B. The first term is identical, but the 3-vector part flips signs, not magnitudes. When one makes time reversal local using quaternion operators, the arrow of time is not a problem because there is a mathematical difference between reversing the reverse of time.

Slashdot Top Deals

"If Diet Coke did not exist it would have been neccessary to invent it." -- Karl Lehenbauer