Nandalion

2003-May-23, 05:24 PM

Is the Unified Field Theory just a bunch of hocus-pocus, or has it actually been proven? Someone teach me, and keep in mind... I haven't sat in a science class in 10 years.

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Nandalion

2003-May-23, 05:24 PM

Is the Unified Field Theory just a bunch of hocus-pocus, or has it actually been proven? Someone teach me, and keep in mind... I haven't sat in a science class in 10 years.

Starjet

2003-May-23, 07:45 PM

I’ll give it a shot. The unified field theory was a term coined by Albert Einstein himself. The unified field theory I think is basically a formula/group of formulas that work together and explain everything that happens in the universe. It governs everything from gravity all the way down to particle motion. It was originally an attempted by Einstein to use geometry to create the formula, which didn’t work. Einstein felt that geometry was a beautiful way the describe the universe, like marble. As you probably know, he came up with a few formulas previously before attempting the unified field theory. His pervious formulas were like marble, simple and elegant, but the other part of it he couldn’t solve with geometry was like wood. He thought that wood was ugly. Anyways, shortly after his death about three years later (formula never found) quantum mechanics came about and completely smashed his ideas of geometry explaining the universe. Quantum mechanics was like wood. Quantum mechanics I really don’t understand all that much, just started to learn about them myself. Everyone explored quantum mechanics for awhile (for information on it search google for it, I can’t explain it that well) and then skip forward a few decades and the superstring theory came out. The superstring theory says that all those subatomic particles are actually strings! The strings are so tiny that it appears as a point particle. When the strings vibrates, like a guitar string, the properties of matter are shown. This theory also uses higher dimensions. You probably must have heard of the 4th dimension or the temporal 4th dimension at least (time). Well, this theory actually uses 9 spatial and 1 temporal dimension I think but it may be 10 spatial (whatever it is someone going to correct all of this anyways, hopefully). All of the formulas and everything we have now become simple and elegant, like marble, in higher dimensions and agree with each other. The reason there are so many dimensions is originally before the Big Bang we had a 10th dimensional universe the existed as a whole. Then, for reasons unknown, space-time ripped apart and the Big Bang explosion happened. The 4 dimensions we know, 3 spatial and 1 temporal, are apparent and the other 6 with shrunk down to the plank length. The plank length is some unbelievable small length that we cannot measure or will be able to measure for the next few centuries. So, in conclusions, there is one but not the one most are familiar hearing about. The superstring theory is of course not proven yet but likely. Please someone look at this and correct any errors, I don’t know much about this stuff myself. Sorry for any inaccuracies!

Bob

2003-May-23, 11:19 PM

I think there is some temporal dislocation in Starjet's tutorial. Einstein died in 1955, and quantum mechanics had evolved to a solid theoretical footing by the late 1920's. Einstein did unsuccessfully devote the latter part of his career into trying to reconcile quantum mechanics and general relativity into a Grand Unified Theory.. Perhaps the string theorists will find the answer.

Starjet

2003-May-24, 01:58 AM

hehe, oops, my bad

DStahl

2003-May-25, 06:26 AM

I think the main idea to get is that physicists hope to find an interlocking set of equations which describe all the forces--all the fields--that we see in the universe.

The game so far:

1. Faraday and some friends found a great set of equations that describe electromagnetism.

2. Nearly 100 years later Stephen Weinberg and some others found a way to link the weak force to the electromagnetic force.

3. Other physicists have managed to describe the strong force, the one that holds quarks and atomic nuclei together, in terms very much like the equations that govern the electromagnetic and the weak force.

In fact, the math these guys have found predicts that the three strongest forces in the universe, the electromagnetic, the weak, and the strong forces, are all aspects of something that was unified in a single manifestation when the universe was very small and very very hot.

4. Gravitation has not been unified with the other three forces. Mathematically it seems really hard to do--when one tries to describe gravitation in equations similar to electromagnetism one gets a bunch of uncancellable infinities, apparently.

A Unified Field Theory would be one kind of a Grand Unified Theory--a set of interlocking, compatible equations that would describe all four of the forces we observe in the universe. As Starjet wrote, Einstein pursued this goal, and any number of physicists are working on it even now. Superstring theory may give us a way to unite all the forces; or perhaps some other path will lead to a GUT.

------

Electromagnetism governs the attraction and repulsion between electrons and protons, and between atoms and molecules. The reason you can't put your hand through a tabletop is because the electromagnetic force keeps the molecules in your hand from shoving aside the molecules of the tabletop.

The weak force mostly shows up in radioactive decay.

The strong force binds quarks into protons and neutrons, and it holds neutrons and protons together in atomic nuclei. But the strong force has a very short range--it doesn't affect things at any great distance.

Gravitation you know about; it's the weakest of the four forces but because all matter particles respond to it and because it can affect things at great distances it dominates the behavior of very large objects.

---

Physicist Sunil Mukhi has a pretty good overview of this at this page (http://theory.tifr.res.in/~mukhi/Physics/string.html).

He writes,

"...today it is believed that the Standard Model is approximate and incomplete. It does not incorporate the fourth and perhaps best-known force in nature: gravity. This is believed to be mediated by the exchange of gravitons, and due to problems of mathematical consistency, no one has ever been able to incorporate gravity into the Standard Model. So it is surely incomplete. Another problem with this model is that one has to assume the existence of distinct forces and their carriers. Einstein hoped that there would be a 'unified' theory in which all known forces would emerge out of a single one in some way. Electricity and magnetism used to be thought of as two forces, but now we know they are different aspects of the same (electro-magnetic) force. Could the same type of unification hold for the four forces that are today viewed as distinct?"

....

"A unified theory would be a mathematical framework in which all the different kinds of forces and particles occur naturally. We should not have to fix the masses and charges of particles from experiment; rather the theory should fix them automatically to be the right values. Why does the electron weigh as much as it does? Why do particles interact with a given strength and not any other? In the standard model we just assume that these values are the ones measured in experiments, but in a unified theory these values should be predicted. Clearly this is an ambitious goal."

The game so far:

1. Faraday and some friends found a great set of equations that describe electromagnetism.

2. Nearly 100 years later Stephen Weinberg and some others found a way to link the weak force to the electromagnetic force.

3. Other physicists have managed to describe the strong force, the one that holds quarks and atomic nuclei together, in terms very much like the equations that govern the electromagnetic and the weak force.

In fact, the math these guys have found predicts that the three strongest forces in the universe, the electromagnetic, the weak, and the strong forces, are all aspects of something that was unified in a single manifestation when the universe was very small and very very hot.

4. Gravitation has not been unified with the other three forces. Mathematically it seems really hard to do--when one tries to describe gravitation in equations similar to electromagnetism one gets a bunch of uncancellable infinities, apparently.

A Unified Field Theory would be one kind of a Grand Unified Theory--a set of interlocking, compatible equations that would describe all four of the forces we observe in the universe. As Starjet wrote, Einstein pursued this goal, and any number of physicists are working on it even now. Superstring theory may give us a way to unite all the forces; or perhaps some other path will lead to a GUT.

------

Electromagnetism governs the attraction and repulsion between electrons and protons, and between atoms and molecules. The reason you can't put your hand through a tabletop is because the electromagnetic force keeps the molecules in your hand from shoving aside the molecules of the tabletop.

The weak force mostly shows up in radioactive decay.

The strong force binds quarks into protons and neutrons, and it holds neutrons and protons together in atomic nuclei. But the strong force has a very short range--it doesn't affect things at any great distance.

Gravitation you know about; it's the weakest of the four forces but because all matter particles respond to it and because it can affect things at great distances it dominates the behavior of very large objects.

---

Physicist Sunil Mukhi has a pretty good overview of this at this page (http://theory.tifr.res.in/~mukhi/Physics/string.html).

He writes,

"...today it is believed that the Standard Model is approximate and incomplete. It does not incorporate the fourth and perhaps best-known force in nature: gravity. This is believed to be mediated by the exchange of gravitons, and due to problems of mathematical consistency, no one has ever been able to incorporate gravity into the Standard Model. So it is surely incomplete. Another problem with this model is that one has to assume the existence of distinct forces and their carriers. Einstein hoped that there would be a 'unified' theory in which all known forces would emerge out of a single one in some way. Electricity and magnetism used to be thought of as two forces, but now we know they are different aspects of the same (electro-magnetic) force. Could the same type of unification hold for the four forces that are today viewed as distinct?"

....

"A unified theory would be a mathematical framework in which all the different kinds of forces and particles occur naturally. We should not have to fix the masses and charges of particles from experiment; rather the theory should fix them automatically to be the right values. Why does the electron weigh as much as it does? Why do particles interact with a given strength and not any other? In the standard model we just assume that these values are the ones measured in experiments, but in a unified theory these values should be predicted. Clearly this is an ambitious goal."

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