Unified Theory

[noz92]

i mean, how did we find it, can we see it, hear it, smell it, whatever, how do we know it's there?

[fuhrerkeebs]

We haven't found it...that's the point. The only reason it came about was because GR makes predictions that are different from experiment...it got blown WAY our of proportions when layman physics books started mentioning it and making it seem like it's the next sliced bread.

[fuhrerkeebs]

If any of you want to try to create your own GUT, you might want to start of by giving maxwells equations in terms of the metric tensor. That's pretty much all you have to do, because that unifies gravity and the electromagnetic field. That's what Kaluza did, he realized that if you assume spacetime to be 5-dimensional (4 spatial and 1 time), then you can give maxwells equations in terms of the extra spatial dimension. And after that, it's easy to unify the electromagnetic field with all the other fields.

 

But on a side note...if you can do that I'll bow down and kiss your feet.

[fuhrerkeebs]

I tried to write out an equation that showed how gravity effected the electromagnetic field once. I did it by giving the electric field in terms of the particles and their charges that were in the field, and applying the equations of motion in a gravitational field to them...but when you have more than one moving particle, it is EXTREMELY complicated, and I soon gave up...and that was before I added in quantum effects!

[[Tycho?]]

We'll find out how right is is from testing it. Newtons laws at first seemed perfect. But over time, small problems and innacuracies began to come up, which eventually led to Einstien developing relativity, which edited a lot of Newtons work, and made it more accurate. I'm sure the same thing will happen with relativity, small little holes are begining to show up, and eventually something else will come along to edit that a bit. We keep editing until we no longer find any problems.

[noz92]

what was wrong with Newtons laws?

[fuhrerkeebs]

They are only approximations to GR. They don't accurately predict the motion of certain planets (such as mercury), they don't predict how much light curves around objects. Newton's laws are background dependent. Newton's laws only deal with a flat spacetime...you can go on and on with this list...

[noz92]

oh.

[fuhrerkeebs]

But, even though Newtonian gravity has all those flaws, for MOST PRACTICAL purposes, it gives a good answer.

[sanjaygeorge]

Any one knows what is the speed of quarks in normal condition?

[noz92]

i don't think that we've proven the existance of quarks yet, so without actual proof that they exist, i don't think it would be possible to have a real idea of what an average speed is.

[Aeschylus]

i don't think that we've proven the existance of quarks yet, so without actual proof that they exist, i don't think it would be possible to have a real idea of what an average speed is.

 

1) We have certainly seen firm evidnece for quarks in scattering experiments, so it's safe to say they exist.

 

2) The speed of a quark, is within the usual relativsstic limitations for tardyons.

[TheProphet]

i don't think that we've proven the existance of quarks yet, so without actual proof that they exist, i don't think it would be possible to have a real idea of what an average speed is.

 

Haven't we? As far as i know of Quarks have been explored quite well.. Even in books from the 60th:s! And even the first experiments with the Neutron to prove an inner particle system of the Neutron proved Quarks and there individual charges... so what u are saying is real time travel too me!

[fermions]

right... I think scientists had bombarded a neutron or proton with a beam of electrons ... then they discovered something hard inside... the electrons were deflected at strange angles...

[TheProphet]

right... I think scientists had bombarded a neutron or proton with a beam of electrons ... then they discovered something hard inside... the electrons were deflected at strange angles...

 

Well further more only at such angles which would indicate a inner 3 particle system now known as the Quarks! And this isn't anything new it's old stuff!

[Severian]

In fact QCD (and its quarks) is the only part of the theory which works as is, without the need for any new particles.

 

(I suppose you could say that QED works too, but since QED probably doesn't exist, that is a bit academic...)

[ydoaPs]

this may help in unified theory: http://www.scienceforums.net/forums/showthread.php?t=5503

 

it is wierd

[noz92]

i just read in an encylopedia that quarks were only theoretical, but it may be out dated, although i wouldn't imagine it since it's a 1996 encylopedia, and wouldn't have many outdated information in it, but in 8 years a discovery could be made i guess?

[ydoaPs]

quarks have been detected in particle accelerators, so i would say they are NOT theoretical.

[TheProphet]

i just read in an encylopedia that quarks were only theoretical, but it may be out dated, although i wouldn't imagine it since it's a 1996 encylopedia, and wouldn't have many outdated information in it, but in 8 years a discovery could be made i guess?

 

Well then their source must be very outdated since some books of my describes Quarks as a mather of fact.. and they are from -54..... But encyclopedias aren't the best source for valid information on such things as Quarks for instance.. go to your library and read a good Fysisks book instead! Even the most introcutionary describes quarks! They even describe the idea of strings altough very very brief...

[Aeschylus]

Well, quarks weren't proposed until 1964 (though the excat history of QCD is a little sketchy to me) and the first experimental evidnce for them came in 1975.

[TheProphet]

Well, quarks weren't proposed until 1964 (though the excat history of QCD is a little sketchy to me) and the first experimental evidnce for them came in 1975.

 

Well since u say that i might just be mistaken by the exact year altough it was written somewhere along 50-60s might just have been late 60:s to then.. haven't really opened that book for long so my mistake if so then

[Aeschylus]

Well since u say that i might just be mistaken by the exact year altough it was written somewhere along 50-60s might just have been late 60:s to then.. haven't really opened that book for long so my mistake if so then

 

Perhaps some parts of the model had already been propsed by then, I really don't know.

 

The actual word 'quark' comes from a poem by James Joyce.

[Luminol]

Einstien's theories showed the existance of black holes before we actually observed them. So the same could be said for string theory...but the problem is trying to see something that is 100 billion billion times smaller than an atom.

 

I thought the idea of dark matter came about when someone was observing a star and noticed that it's light was being bent like there was a large unseen object that came into the field of view...and also the fact that there isn't enough matter in the universe to explain expansion/contraction of the universe.

 

There are some good books out there about string theory/TOE that are easy to understand like "the Elegant Universe (also on DVD from PBS very very good!), Beyond Einstein, The Universe in a Nutshell (covers a lot of stuff).

 

Quarks are part of modern physics (the feel the strong force which holds the atoms together)...elementary particle physics which is kind of at war with string theory since particle physics has been able to unify all of the forces in the universe accept for gravity. String theory basically unifies quantum mechanics and the theories of relativity (this quest started to help explain black holes...very small and very dense...but neither theory could be used to explain the world of the other) String thoery "smoothes out" space/time at super small scales...which was the problem relativity had at small scales...things didn't make sense.

 

There are 5 string theories and one called 11-dimensional super gravity...M-theory is believed to be the theory that all of these describe...it's kind of the unification theory of string theory.

[ydoaPs]

There are 5 string theories and one called 11-dimensional super gravity...M-theory is believed to be the theory that all of these describe...it's kind of the unification theory of string theory.

 

the illustration of blind men describing an elephant is often used for that.

 

blind men each grab a different part of an elephant and describe it. all of the decriptions are different, yet they describe the same elephant. m-theory is the elephant, and the string theories are the blind men's descriptions.