Unification and Why...

[vacuodynamic]

Well, no, according to General Relativity spacetime is actually being distorted and curved by the presence of a mass. It is physically happening, and spacetime is curved. The geometry of spacetime is distorted. The bowling ball on trampoline is just an analogy we use to help us visualize the concept. Note that I am using the term spacetime because you cannot have space without involving time as well.

 

Dear Reaper and friends,

 

According to general theory, space-time was curved in the present of the near by mass, it is alright, but there are two remaining questions involved! The first one is “how space-time is curved while it is an empty space-time”? The second question is “why mass causing space-time to be curved”?

 

At first sight, it seems that Einstein could explain the “mechanism” of gravity, while Newton could not. Actually both of their theories have the same position about gravity, the only difference is that Newton explanation is a simple and approximate one, while Einstein explanation is elegant and more accurate, but also more complicate!

 

Sincerely

Edited July 30, 2008 by vacuodynamic
some correction

[Klaynos]

Science tends not to deal with why... that's more philosophical.

[vacuodynamic]

Science tends not to deal with why... that's more philosophical.

 

Dear Klaynos and friends,

 

Is science a magic? I don’t think so. Everyone knows that “understanding” is the progression of science! Actually, it seems that physicists want to understand all of the natural phenomena, unless they could not do that but too be ashamed to accept it. This may be the greatest problem of modern physics theories today!

 

It is interesting to note that nowadays modern theoretical physicists want to find ‘the theory of everything”, while they don’t try to understand the fundamental physics first. For example, they try to combine general relativity with quantum mechanics. How could they success, while they do not understand both theories completely?

 

Sincerely

[Klaynos]

Dear Klaynos and friends,

 

Is science a magic? I don’t think so. Everyone knows that “understanding” is the progression of science! Actually, it seems that physicists want to understand all of the natural phenomena,

 

Understand, is how, not why, why implies some greater purpose.

 

unless they could not do that but too be ashamed to accept it. This may be the greatest problem of modern physics theories today!

 

Sure.....

 

It is interesting to note that nowadays modern theoretical physicists want to find ‘the theory of everything”,

 

This a theory that unifies the 4 fundamental forces, nothing else.

 

while they don’t try to understand the fundamental physics first.

 

Like what? The unification of the 4 fundamental forces is arguable as fundamental as you can get.

 

For example, they try to combine general relativity with quantum mechanics.

 

For most things they are compatible, a theory of everything would do this as it would include a quantum theory of gravity

 

How could they success, while they do not understand both theories completely?

 

How do you feel you're qualified to comment without understanding what they have and what they are hoping to find?

[vacuodynamic]

Understand, is how, not why, why implies some greater purpose.

 

Would you please give some examples?

 

This a theory that unifies the 4 fundamental forces, nothing else.

 

Yes, it is, but how to unify them together?

 

Like what? The unification of the 4 fundamental forces is arguable as fundamental as you can get.

 

Like, what is the mechanism of gravity, how and why masses attract each other? The same question for electromagnetism, weak force and strong force!

 

For most things they are compatible, a theory of everything would do this as it would include a quantum theory of gravity

 

Yes it does, but how to combine general relativity with quantum mechanics to be quantum gravity, while both of them are inconsistence to each other? Also both the theories are lacking of its black ground philosophical idea (mechanism) which explain how they work!

 

How do you feel you're qualified to comment without understanding what they have and what they are hoping to find?

 

I dare not to think that I am smarter, but only try to understand!

 

Sincerely

[Klaynos]

Would you please give some examples?

 

Quantum mechanics, special relativity, general relativity,

 

Yes, it is, but how to unify them together?

 

In a similar mannor to how electrodynamics unifies magnetism and electricity, or how the electroweak force is unified with electromagnetism. Mathematically backed by experimentation.

 

Like, what is the mechanism of gravity, how and why masses attract each other? The same question for electromagnetism, weak force and strong force!

 

How masses attracted will be answered by a unification theory. EM, weak and strong have already been answered, have a look at quantum electrodynamics, quantum chromodynamics, and electroweak theory. Why is another question, why implies they have a reason a purpose, and is not science.

 

Yes it does, but how to combine general relativity with quantum mechanics to be quantum gravity, while both of them are inconsistent to each other? Also both the theories are lacking of its black ground philosophical idea (mechanism) which explain how they work!

 

They are not inconsistent, general relativity breaks down and gives singularities, a quantum theory of gravity, or a ToE (theory of everything) would deal with this.

 

Science doesn't care much for philosophical ideas, science cares that when you throw a rock it hits the ground...

 

I dare not to think that I am smarter, but only try to understand!

 

I didn't say anything about how smart you are, but you don't seem to grasp what the current theories include, or what a ToE would contain.

 

It's interesting most people go with the view "once there's a ToE physics will be dead" you've gone the other way It should also be remember that ToE and GUTs (grand unified theories) are not the only thing physicists are working on.

[vacuodynamic]

Dear Klaynos and friends,

 

Quantum mechanics, special relativity, general relativity,

 

For these theories, how “why” implied for them?

 

In a similar mannor to how electrodynamics unifies magnetism and electricity, or how the electroweak force is unified with electromagnetism. Mathematically backed by experimentation.

 

As I know, nowadays gravity still cannot unified to the others, can it?

 

How masses attracted will be answered by a unification theory. EM, weak and strong have already been answered, have a look at quantum electrodynamics, quantum chromodynamics, and electroweak theory. Why is another question, why implies they have a reason a purpose, and is not science.

 

What is the unification theory mentioned?

 

Is it means that” why masses attract each other?” have a reason a purpose and it is not science? Then what is the reason a purpose?

 

 

They are not inconsistent, general relativity breaks down and gives singularities, a quantum theory of gravity, or a ToE (theory of everything) would deal with this.

 

Science doesn't care much for philosophical ideas, science cares that when you throw a rock it hits the ground....

 

That is the greatest problem for science which trying to finding TOE but still not success!

 

I didn't say anything about how smart you are, but you don't seem to grasp what the current theories include, or what a ToE would contain.

 

Please explain more specifically about “you don’t seem to grasp the current theories include or what a TOE would contain.”

 

It's interesting most people go with the view "once there's a ToE physics will be dead" you've gone the other way It should also be remember that ToE and GUTs (grand unified theories) are not the only thing physicists are working on.

 

But all of them are not yet success, are they?

 

Sincerely

[Klaynos]

Dear Klaynos and friends,

 

 

 

For these theories, how “why” implied for them?

 

Why do electrons have a wave particle duality? The question is not answered in QM, we can tell you how, but not why.

 

As I know, nowadays gravity still cannot unified to the others, can it?

 

No, neither is the strong force. It is being worked on.

 

What is the unification theory mentioned?

 

I mentioned two, QED, quantum electrodynamics, and QCD quantum chromodynamics.

 

The first is the unification of the EM forces, which was the first modern unification theory devised, and was done by maxwell, and the second is the unification of EM and electroweak.

 

Is it means that” why masses attract each other?” have a reason a purpose and it is not science? Then what is the reason a purpose?

 

Asking for a reason is not science, so I cannot be answered here, you're best finding a philosophy forum.

 

That is the greatest problem for science which trying to finding TOE but still not success!

 

Are you saying the not caring about fluffy words is teh great problem for finding a ToE which would be a mathematical formalisation... as is required by modern physics, else it's untestable and not a theory.

 

Please explain more specifically about “you don’t seem to grasp the current theories include or what a TOE would contain.”

 

Your previous posts, claiming QM and GR are inconsistent, this is a common mistake so we can let that one pass after correction, but in your first post you said:

 

It is interesting to note that nowadays modern theoretical physicists want to find ‘the theory of everything”, while they don’t try to understand the fundamental physics first. For example, they try to combine general relativity with quantum mechanics. How could they success, while they do not understand both theories completely?

 

You claim they're not understood completely, and that unification wont help this but unification will be an addon to both theories it wont replace them, just as SR adds to classical mechanics, or more relevantly quantum electrodynamics dynamics adds to electrostatic and magnetostatic theories.

 

But all of them are not yet success, are they?

 

No, it's being worked on.

[ajb]

Are we mixing the "whys" and the "hows"?

 

General relativity tells you how matter and energy couple to gravity via space-time curvature.

 

One interesting point is that vacuum solutions, for example the Schwarzschild solution have non-trivial curvature. In fact, most of the solutions I know are vacuum solutions.

 

Do we what to discuss the philosophy of unification in physics?

[vacuodynamic]

Dear Klaynos and friends,

 

Why do electrons have a wave particle duality? The question is not answered in QM, we can tell you how, but not why.

 

“The question is not answer in QM.” Is it because it is philosophers’ duty so there is no need for scientists to know, or it is necessary for scientists to understand, but can not done yet?

 

 

Asking for a reason is not science, so I cannot be answered here, you're best finding a philosophy forum.

 

Is the reason that we not asking for because it is not science and it is useless or because we (scientists or philosophers) can not understand it?

 

Are you saying the not caring about fluffy words is teh great problem for finding a ToE which would be a mathematical formalisation... as is required by modern physics, else it's untestable and not a theory.

 

Sorry, I am not so good in English; would you please explain it again?

 

You claim they're not understood completely, and that unification wont help this but unification will be an addon to both theories it wont replace them, just as SR adds to classical mechanics, or more relevantly quantum electrodynamics dynamics adds to electrostatic and magnetostatic theories.

 

I am not so clear about the meaning of “adding”. Anyway, let’s see for an example about SR and classical mechanics. We know that SR is more general and accurate than classical mechanics, so could we say that classical mechanics was replaced by SR?

 

Sincerely

[Klaynos]

Dear Klaynos and friends,

 

 

 

“The question is not answer in QM.” Is it because it is philosophers’ duty so there is no need for scientists to know, or it is necessary for scientists to understand, but can not done yet?

 

Is the reason that we not asking for because it is not science and it is useless or because we (scientists or philosophers) can not understand it?

 

I'll answer both of these bits together, it's more of a philosophy question I suppose as it can't be quantified, it also implies an intelligence which is not found outside biology.

 

Why do planets orbit stars? Because they like stars but also like their own space...

 

How do planets orbit stars? Gravity and centralfugal forces balancing....

 

Sorry, I am not so good in English; would you please explain it again?

 

Of course.

 

A theory of everything, will be mathematical, it will also be backed up by evidence. Are you suggesting that we should stop looking for that (which is science), and just try and come up with word descriptions of the universe?

 

I am not so clear about the meaning of “adding”. Anyway, let’s see for an example about SR and classical mechanics. We know that SR is more general and accurate than classical mechanics, so could we say that classical mechanics was replaced by SR?

 

Yes, classical mechanics is not complete, SR adds something to classical mechanics, but for "normal" situations the SR equations simplify into classical mechanics equations, the same is true for general relativity (GR), it is an addition to SR, so for the situations where SR is valid, if you apply GR the equations simplify to the SR equations and then if it is a classical question the equations simplify all the way down to classical equations.

 

All of modern physics is interlinked very closely with all the rest of it. It's rather cool

[JTM³]

It should also be remember that ToE and GUTs (grand unified theories) are not the only thing physicists are working on.

 

OOO, what are these 'other' things you say physicists are working on?

 

(seriously!)

 

JT

[Klaynos]

OOO, what are these 'other' things you say physicists are working on?

 

(seriously!)

 

JT

 

Well the best thing I can do for you is give you a link to the research groups at my university:

 

http://newton.ex.ac.uk/research/

 

That is a TINY area of active physics research, my areas of that have ranged over a few whilst being an undergrad:

 

Visible domain meta materials

magneto-optical spectroscopy of thin films

Physical and optical properties of photonic crystals in a weevil species

 

I'm soon to be working on THz devices...

 

Another place to look is arxiv:

 

http://arxiv.org/

 

Have a look through the physics section...

 

Or one of the many journals like:

 

http://prl.aps.org/

[vacuodynamic]

Dear Klaynos and friends,

 

I'll answer both of these bits together, it's more of a philosophy question I suppose as it can't be quantified, it also implies an intelligence which is not found outside biology.

 

Why do planets orbit stars? Because they like stars but also like their own space...

 

How do planets orbit stars? Gravity and centralfugal forces balancing....

 

 

What about these explanations?

 

Why do planets orbit star? Because gravity and centrifugal balancing.

 

How do planets orbit star? They do according to Newton gravitation law.

 

 

Of course.

 

A theory of everything, will be mathematical, it will also be backed up by evidence. Are you suggesting that we should stop looking for that (which is science), and just try and come up with word descriptions of the universe?

 

Of course not!

 

A good theory should have philosophical idea which explains how it works, together with mathematical formula which was used as the predicting tool. Of course, the main goal of the theory is to make a prediction, but if we understand its mechanism it will give us more confidence in the theory, otherwise it may lead us to something crazy!

 

 

Yes, classical mechanics is not complete, SR adds something to classical mechanics, but for "normal" situations the SR equations simplify into classical mechanics equations, the same is true for general relativity (GR), it is an addition to SR, so for the situations where SR is valid, if you apply GR the equations simplify to the SR equations and then if it is a classical question the equations simplify all the way down to classical equations.

 

Yes, we all know that, but it would be better if we know why the classical mechanics work as it does. Also, understanding why SR which is more general working. Are we confident that SR is a really complete one, while we do not know the reason behind? What we do know is only because it is due to the Lorentz transformations, but what is it physical meaning?

 

 

All of modern physics is interlinked very closely with all the rest of it. It's rather cool

 

Indeed it is, but it would be better if we know how it links together,isn't it?

 

Sincerely

[Royston]

Dear Klaynos and friends

 

This isn't correct, Klaynos has no friends.

 

Of course not!

 

A good theory should have philosophical idea which explains how it works, together with mathematical formula which was used as the predicting tool. Of course, the main goal of the theory is to make a prediction, but if we understand its mechanism it will give us more confidence in the theory, otherwise it may lead us to something crazy!

 

You don't need philosophy to understand the mechanism, or 'how' it works...that's the role of physics. A testable mathematical model that predicts the results...that would explain the 'how.'

 

The why questions only go so far, e.g why does a single electron seem to occupy both slits in a two slit diffraction experiment (you could set up a number of interpretations), then you would go about creating a model that would explain 'how' that is possible. The successfull model would whittle down the initial interpretations of the experiment. Philosophy sets the initial questions, that's all.

 

Are we confident that SR is a really complete one

 

It does perfectly well at explaining phenomena for certain situations.

 

What we do know is only because it is due to the Lorentz transformations, but what is it physical meaning?

 

The physical meaning can fall out of the equations, e.g appropriate frames of reference when doing velocity transformations, as well as time dilation and length contraction, all have physical meaning, and they're predicted by the equations.

[pioneer]

There a basic unanswered whys, like why quanta exist. This "why" will affect everything. That should be the foundation. Instead we build in the air. We have this huge mythological city floating above the earth defying gravity. There is a gap between the city and the earth. In other words, if quanta are due to fairies, unicorns, energy, time, each of these changes everything. As long as the gap remains the magical city is safely floating in the air. It can't land because it is not natural to build in the air without a basic foundation. The affect is real but without why it is a correlation that isn't rational. It is a loop that is self feeding allowing it to levitate.

[ajb]

Maybe pioneer, but physics deals with what we can measure and how we can calculate using mathematical models things that we can measure. Everything else in between is almost irrelevant.

 

More importantly physics does not attempt to ask the question "why". Even "how" is not really answered. All we have are mathematical models that we can use via calculation to describe nature and make predictions.

[vacuodynamic]

Dear Snail and friends,

 

This isn't correct, Klaynos has no friends.

 

Is it so? Anyway, he is still one of my friends!

 

You don't need philosophy to understand the mechanism, or 'how' it works...that's the role of physics. A testable mathematical model that predicts the results...that would explain the 'how.'

 

For me, a mathematical model seems only “telling”, not “explaining” which will give us “understanding” how it works!

 

Sincerely

 

Dear ajb, pioneer and friends,

 

Maybe pioneer, but physics deals with what we can measure and how we can calculate using mathematical models things that we can measure. Everything else in between is almost irrelevant.

 

More importantly physics does not attempt to ask the question "why". Even "how" is not really answered. All we have are mathematical models that we can use via calculation to describe nature and make predictions.

 

It is interesting to note that mainstream physicists try to find the theory of everything while they don’t try to asking “how and why” about modern physics theories involved! How could they achieved it without “understanding” their work?

 

Sincerely

[Klaynos]

Dear Snail and friends,

 

 

 

Is it so? Anyway, he is still one of my friends!

 

 

 

For me, a mathematical model seems only “telling”, not “explaining” which will give us “understanding” how it works!

 

But the maths gives us the understanding of how it works. Nothing else can, there's nothing else we can test against... I can claim that it's all little invisible pixies there's no way to prove me right or wrong, it's not science.

 

Sincerely

 

Dear ajb, pioneer and friends,

 

 

 

It is interesting to note that mainstream physicists try to find the theory of everything while they don’t try to asking “how and why” about modern physics theories involved! How could they achieved it without “understanding” their work?

 

Sincerely

 

They do understand their work. They understand it very well. They do ask how... it's something which is asked alot, but why implies reason which implies intelligence... and that can't exist in physics.

[fredrik]

I suppose the words why and how are a bit of a problem to start with.

 

It's often repeated that science describe what we know about nature ~ how. But not "why" nature is the way it is. That sounds somewhat reasonable but one can still find a meaning of the why question in science I think.

 

From the scientific point of view, if the how describes our best knowledge or "guess" about nature, one interpretation of why would be - WHY do we have this opinion? ie. How have we concluded from experience and history this standpoint?

 

This is to probe the logic of the scientific method.

 

A very trivial meaning of how, in order to avoid uncertain propositions is to consider the extreme case of only describing the past. We only know how nature behaves AFTER we have witnessed it.

 

But then, the whole utility of science, as opposed to history, is to use our experience and from that form an expectation of future expectations. The utility is then that we can chose our actions, as per expectations, to our advantage.

 

In that sense why could we a hypotetical connection between two factual events. Or the idea that the current state, predicts the future state (wether deterministically or probabilistically). Then this causation could be thought of as the scientific version of "why".

 

Why is the ground wet?

The ground is wet because it was raining one hour ago.

 

To ignore the why would be to say that, we know for sure the ground is wet, and indeed it was raining one hour ago but any possible connection is not of interest.

 

But it seems that nature of this problem suggests that there is never a confident why. We can not with certainty infere a causal relation from the past. All we can do is guess, or in Poppers world: come up with the hypothesis that raining wets the ground, and try to falsify it.

 

I see one of the utility of sciece is in these key questions

 

This is the state of matters today, what will happen tomorrow?

 

This is our experimental setup, what will the outcome be when we fire the experiment?

 

That can be interpreted as implicitly asking "whys" as in how a particular initial state are expected to evolve into a posterior state. The why is the causal relation. It does not have to be error free or deductive to be of utility.

 

In a way scientific theories are the whys. If we again ask why as in "why this why" that IMO is to question the scientific method - can we trust the method that has lead us to this why?

 

This leads to discuss philosophy of science. OTOH, if we consider that the scientific model is reall nothing but a "theory or method of learning" one can certainly try to improve it.

 

There has been philosophers that has apparently been annoyed by the lack of certainty and tried to find ways to evade it. But I think that we must not let the imperfections blind us and prevent us from making progress.

 

To try to gain knowledge of nature is IMO not a deductive process, it is a risky game. As I see it, science as opposed to occuly of religious framworks aims to optimize the game to the extent possible. Natural science isn't mathematics and we don't prove things. We don't prove laws.

 

And even the laws should constantly be challanged.

 

/Fredrik

[ajb]

Maybe I should just clear up my statement on "how". By "how" I mean a statement in words that describes "what is going on". The reality of this is that physics being a mathematical pursuit, can only answer "how" by describing a calculation or mathematical construction. This is usually called by people in theoretical/mathematical physics an "interpretation".

 

This is why many of the answers to how can seem very strange and unintuitive. They are really interpretations of mathematical statements. These can be extremely useful in explaining ones results and can guide further ideas. These interpretations are usually what popular science books concentrate on. They describe mathematical calculations in words.

 

Sometimes, these "physical interpretations" can also be useful in pure mathematics. This has been on of the big successes of string theory and QFT. People can reproduce well known mathematical theorems and results using physics.

 

"Why" is not a question that physics can answer or indeed sets out to answer. "How" is (partially) answered using an "interpretation", which is basically a way of describing the calculation. The fundamental things in physics are those that can be measured.

[vacuodynamic]

They do understand their work. They understand it very well. They do ask how... it's something which is asked alot, but why implies reason which implies intelligence... and that can't exist in physics.

 

Dear Klaynos and friends,

 

Let’s discuss one fundamental problem in gravity, to see whether they could understand it; why masses attract each other?

 

Sincerely

Edited September 3, 2008 by vacuodynamic
word corecction

[ajb]

"Why" I have no idea. Physics can't really answer that.

 

I do of course know how to describe how masses interact gravitationally, c.f (non-relativistically) Newtonian gravity or (relativistically) general relativity.

[Klaynos]

"Why" I have no idea. Physics can't really answer that.

 

I do of course know how to describe how masses interact gravitationally, c.f (non-relativistically) Newtonian gravity or (relativistically) general relativity.

 

I agree with this.

[Martin]

Dear Klaynos and friends,

 

Let’s discuss one fundamental problem in gravity, to see whether they could understand it; why masses attract each other?

 

Sincerely

 

I think I understand your question. It has to do with what AJB said, namely "what is going on" and what math models you use to calculate what is going on---when two masses attract.

 

Don't be put off by fine verbal distinctions, if your question could just as well be phrased how do masses attract each other?

 

Is that what you mean to ask? Probably. Anyway it is a good question.

There are various mathematical models of what is going on, and the simplest is only approximate.

 

there are layers of explanation to dig down thru.

 

the Newtonian description of how two masses attract uses point masses and force vectors. it is only approximate. it doesn't give the right answer for Mercury's orbit, for example. but it is nearly right for most things

 

then you go deeper and ask how does it really work and what is really going on, and you get another better but still partial, answer. the dynamic metric (or distance function) of Gen Rel. there is a metric that descibes geometry, and the metric is influenced by mass, energy, momentum----in simple cases it boils down to the energy density in space. (and the masses you asked about have their energy equivalent and contribute to that density.)

 

so this is still pretty simple----the two masses affect the energy density in space, and that affects the shape, the geometry, by affecting the metric (the distance function, also called the gravitational field----in Gen Rel the gravitational field is simply the geometry of space and time, gravity is nothing but geometry)

 

the energy density affects the geometry and the geometry detrmines the orbits----and now we get the right answer for Mercury and all that good stuff out to the 6 or 7th decimal place. :smile:

 

but you can STILL ask, and you can still try to dig down to a deeper layer!

In science you can always do this. there is always a deeper law underlying the law you are told. you can ask how does the distribution of mass affect the geometry.

this gets into the field called quantum gravity. it asks some more basic questions that underlie Gen Rel.

What is the microscopic geometry of space and time?

At some level matter and geometry must be the same thing, described by the same mathematical descriptors (technically called degrees of freedom) so that since they are the same thing it is obvious how they interact. At a deeper microscopic level, matter must simply be a facet or aspect of geometry (according to some quantum gravity models at least) so it is no longer a problem of how one affects the other---they are the same.

OK that is speculative, but you see one way how it could go.

 

the basic question, then, at this level is What is the microscopic geometry of space and time? The degrees of freedom, the descriptors, that underlie Gen Rel---and probably behave according to quantum mechanics rules.

 

So if you want to see what the people are doing that dig down to that level, and it is work in progress, then one excellent window on it is the Loll article in Scientific American. I have the link in my sig. The Loll group does computer simulations of the microscopic structure of spacetime. they have little random universes pop into existence in the computer, and they study them. they run random walks that wander around inside them, they measure stuff about the little quantum universes. and they average them up to get a smooth largescale average somewhat like our observed universe.

 

there are many types of quantum gravity research, but this one has reached a very concrete stage, so it is an accessible example of where a lot of quantum gravity research is heading and will probably be going.

And it is an easy reading article with lots of pictures, so it gets across the main ideas.

 

so if you want to know what underlies Gen Rel and how matter affects geometry of spacetime, then the question you should have in mind is one that current research is working on (and hasn't answered conclusively yet) namely what is the quantum microscopic structure of spacetime that underlies General Relativity?

 

Does this respond to your question, or did you have something else in mind?