# A few fundamental questions I'm having trouble on

1. Apr 12, 2007

### PhysicsGnome

Why is an electron so small and the proton so large?
Why does + repel + and all those other combinations?
Why exactly does an electric field form?
What is + charge?
What is - charge?

I'm looking for very indepth stuff here.

Last edited: Apr 12, 2007
2. Apr 12, 2007

### lpfr

Physics study the "how" of nature but not the "why".
It is theology that knows the "whys" for sure.
Physics cannot answer to questions like "why are two kinds of charge" or "why there was a big bang". Physics can tell you that things in nature "tend" to diminish the potential energy of a system and this is why two opposite charges attract. But physics cannot tell you why things in nature "tend" to diminish the potential energy.
Most of question you posed are of the kind "why the world is as it is". Science cannot answer this type of questions. And I think that the need for an answer has pushed men to create gods and religions. But, of course, this is just a personal feeling.

3. Apr 12, 2007

### Mentz114

lpfr, I would like to endorse those sentiments.

Physicsgnome, you need to rephrase your questions. 'Why' is for philosophers.

4. Apr 12, 2007

### Claude Bile

I would say physicists DO hope to answer these fundamental questions, but also recognise that once you explain a "fundamental" concept, then really, it is no longer fundamental. Throughout history, physicists have uncovered layers underneath what we once thought to be fundamental - who knows what will be considered fundamental 200 years from now?

Claude.

5. Apr 12, 2007

### Ki Man

If a how answer is good enough for you, it is because a proton itself is made of 3 peices that are just as large as electrons, and the rest of the mass is a result of the bonds. http://nobelprize.org/educational_games/physics/matter/13.html" [Broken] has some good stuff about why protons are 'huge'

Last edited by a moderator: May 2, 2017
6. Apr 18, 2007

### PhysicsGnome

I think the "we can't answer these types of questions" are a load of crap... If something does not make sense, then you don't know how it works.

Why is not for philosophers in my opinion. Why is a weakness in a physicists's understanding that philosophers speculate on. Why does an apple fall? Hmm, there must be something pulling it down if it's not held in place....Why does it not fall off the tree? Hmm the force pulling it down must be weaker than the force it would take for me to pull it off the tree myself.

How is less powerful than why...
(Really what is the most powerful I would say is "what" since "Why" = what is the purpose of this? anyway...)

Thanks for the response Claude and Ki man, those were at least informative.

Is there any current research going on that is trying to answer any of my questions? I'm a physics student at a university, so I'm interested in these basic questions that seemed to have slipped by me as I go deeper into this stuff.

7. Apr 18, 2007

### Mentz114

True. Do you have something in particular in mind that makes no sense ? Why should an electron not have 1/1000 the mass of a proton ?

That's a fair question but I don't know the answer, it wasn't in any book or course I ever took.

Go for it PhysicsGnome, perhaps in years to come you can enlighten us.

8. Apr 18, 2007

### lpfr

Next time you ask something I wont bother to give you "a load of crap".

This is part of the physics "how" and the answers are known.
I think that you have not understood the differences between the "whys" and the "how's".

9. Apr 18, 2007

### masudr

Why does the apple fall?

Some ancient religious types said it was because the earth is at the centre of the universe and everything has a tendency to settle there, at the proper position of absolute rest. They were wrong of course, but they still answered the why question.

Newton's answer was that there is a gravitational force between the apple and the earth proportional to the product of their masses divided by their separation squared. Right, so there's your why question answered.

But wait: why is there a gravitational force between the apple and the earth in the first place? Even Newton (nor many of the geniuses that came after him) didn't know why. They don't know how it works, you say? And Newton was also wrong, by the way.

Well, Einstein's answer was that there is no gravitational force whatsoever! No: instead in the presence of matter/energy, spacetime is curved. The upshot of this is that particles left by themselves follow geodesics (their motion satisfies the geodesic equation) and there are terms in those geodesic equations that are related to the curvature of spacetime.

But wait: why is spacetime curved in the presence of matter/energy? Even the great Einstein has no answer to that question. He doesn't know how it works, you say?

So, my point is that firstly answering "why" in physics can get you a better understanding, but always leaves behind another why question (see note 1). The onion that is nature has an infinite number of layers, if you will. What the first two replies to your post were trying to say was that if you have asked your questions hoping for some kind of final definitive answer, then you won't get them.

"But," I hear you say, "I didn't ask for a final definitive answer." Well in that case I can kind of unravel a layer and answer the first why question. The reason is that electrons are leptons which cannot posess colour. Protons are made up of quarks which do. This allows 3 quarks to exist together (as there are 3 colours). A proton is made up of 3 quarks (up, up and down quarks, if I remember correctly). Furthermore they are basically orbiting their common center of mass (in the same sense electrons orbit nuclei), all in their gluon field. The proton is basically what these 3 quarks doing this stuff looks like from far away: we can't see their gluons, and they weigh a lot more because of the energy of the gluon field.

But, of course, you can ask why don't leptons have colour? And that is a question I cannot answer, as we just don't know. And that's what the first two replies were trying to say, but perhaps in less words. Never mind, though, you didn't ask for a final definitive answer, anyway.

1. An interesting sidepoint regarding answering why questions in physics: in mathematical terms, answers to why questions (when correct, of course!) become simpler, but in layman's English, they become more and more complicated. See how the concepts used became more and more technical each time a why question was answered above.

A general note on forum behaviour: when you have just joined a forum it is not nice to behave unappreciatively to people who try to answer your questions. It just plain puts you in a bad light. And whilst you may not care for that, the quality of answers you get to your questions usually highly depend on that.

Last edited: Apr 18, 2007
10. Apr 18, 2007

### rewebster

my, my, my---

Why are some people so touchy about the word 'why' when it comes to physics?

hmmm, hmmm, hmmm---

I think it may come from that 'physics' WAS once in the area of philosophy, and some physicists may not like to be reminded of this--like they are defending a more 'nobel' area.

A 'why' question CAN lead to another 'why' question---of course; but, a 'how' question can just as easily.

One online dictionary (http://www.m-w.com/cgi-bin/dictionary) defines 'why' as: ": for what cause, reason, or purpose".

--and 'how' as: "b : for what reason : WHY " ----

funny!

A 'how' question can be just as philosophical as a 'why' question---

Personally, I think it's impolite to automatically (as if by some 'physics axiom') to NOT answer the question if the question has a 'why' in it with the dogmatic response that a 'why' question is of a theological/philosophical nature, and as if the question isn't worth answering ('this is beneath me/incorrect').

Last edited: Apr 18, 2007
11. Apr 18, 2007

### masudr

Well, hang on rewebster:

Answering why questions doesn't really get you very far... how questions do. Look at this:

How does the apple fall to the ground?

The earth sets up a grav. field

$$\nabla^2\phi_g = 4\pi G_c \rho$$

and the apple experiences acceleration given by

$$\vec{g}=-\vec{\nabla}\phi_g.$$

The how question is just generally better answered by physics than the vague answer to the why question above. And answering why questions doesn't get you any closer to the physics, but the how questions do.

So while answering why questions might give you a feel for the subject, answering how questions actually gets to the meat of it.

To paraphrase Feynman: "years ago people thought the angels pushed the earth around its orbit, but now we know that the angels push the earth inwards."

The why questions remain just as mysterious.

12. Apr 18, 2007

### rewebster

yes-- I'm aware that 'how' may be a little 'more' correct---but that is not the point here---

It's as if some don't care about the question as much as correcting, say, a spelling errer [sic].

-----------------------------------------------------

How does the apple fall to the ground?

OK--how does gravity work?

I see no difference to ask --why does gravity work the way it does?

-------------------------------------------------

how many angels can dance on the head of a pin?

Last edited: Apr 18, 2007
13. Apr 18, 2007

### AngeloG

The why of things is a difficult subject.

There's a billion of wrong and right answers; all rhetorical of course =p.

Hehe, but it's interesting with forces =). Why do like charges repel and why doesn't gravity? Is it the very nature of this Universe?

Last edited: Apr 18, 2007
14. Apr 18, 2007

### masudr

Fair enough; but even you must admit that this is a rather contrived question. Furthermore, this question is perfectly answerable, once you precisely define what a pinhead is and what an angel is.

15. Apr 19, 2007

### PhysicsGnome

It seems to me that more brain power is wasted on arguing about all this crap instead of trying to actually figure it out. Why all the argument? Thanks for the info though Masudr. Btw, I thought that einstine said that space time curved from matter/energy because of the geometry of higher dimensional space... That's where all the debate about string theory comes in and how we can't find "our solution" out of all the solutions there are for possible universes. Einstine's problem was trying to combine the random world of particles (wood) with his precise world of geometry (marble) without having the knowledge we have today.

I would say asking any type of question to point out flaws in understanding is the best way to go. At least you know what you don't know then.

So I at least learned that the reason I don't know the questions I asked is because we don't really know anyway. Hopefully we'll quit arguing and just try to solve this stuff.

16. Apr 19, 2007

### rewebster

Well, that 'perfectly answerable question' then would go into the 'applied' area ---if the parameters/characteristics are defined and known, not the 'theoretical' area--

-Which, it seems to me is one of the bigger problems, especially on discussions as some of questions such as PhysicsGnome's are more 'theoretical' and not sometimes answerable yet (well, at least not by the 'accepted' /'published' circle ).

People with 'theoretical' in mind will tend toward thinking more of 'why' questions as an 'hypothesis' when it comes to a question relating to physics, and take it as a creative challenge to try to figure out the mystery.

Applied physicists, as it seems that most of the people who answer most of the questions may think, or may have been more trained that 'why' questions are not meant for them, as much as 'how' questions are (how can I TEST this idea?--since I now know definitively WHAT the pinhead is and WHAT the angel is).

PhysicsGnome---"So I at least learned that the reason I don't know the questions I asked is because we don't really know anyway. Hopefully we'll quit arguing and just try to solve this stuff."

There's new 'theories' coming out everyday. There are some partial answers to some of your questions (such as you may find on wiki), but you may be thinking or wanting very exact 'answers' which haven't been published/theorized yet.

17. Apr 20, 2007