Electro-Magnetic-Space/Time Continuum?

[CptTrips]

OK.  I’m probably going to make myself look like an idiot here but it’s something that’s been bothering me, literally for years.  There seems to be some pretty sharp knives in the drawer here so maybe you can help.

I’m currently listening to :

“The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos”  (Brian Greene)
On my Audible books.  Its pretty interesting.  I recommend it.

In one section, he goes over the whole story about how Einstein was perplexed by the question of exactly HOW two objects, with no direct connection to, or contact with each could transmit a gravitational force between each other.   These objects might be in a complete vacuum with no matter between them at all.  What is the EXACT mechanism by which the force is mechanically transmitted???

The standard answer was “well,uhh, it’s the gravitational field”. But what does that MEAN?  You might as well be saying “magical spirits.”  What is the EXACT mechanism by which the influence is transmitted.  “Where are the invisible ropes” by which one object pulls on another, he asked.   Even Newton recognized it was an unanswered question at the time he was formulating the laws describing the results.  That led Einstein to develop the theory of curved space/time. It wasn’t so much that a magical force was being applied to an object, as the object moving thru curved space/time just looked like a force was being applied.   Great story.  All makes sense.  Bowling ball sagging a trampoline, roll on an cueball…follows the curve..yadda yadda.  Got it. 

Then the very next chapter he go into this whole section on magnetism and how objects are influenced by “magnetic fields”.   And that touched off a thing that’s been bothering me a long time.   Why is “magnetic field” any more a satisfactory answer than “gravitational field”???  What is the exact mechanism by which magnetic force is transmitted between objects that might be separated by complete vacuum???  Where are the invisible ropes? It BEGS the question, but he never even notes the parallel or I missed it.  Why doesn’t it beg the same question?

I’ve asked a lot of people, a lot smarter than me: “Yeah, but HOW does it transmit the force?  By what mechanism?“  The standard answer was “well uh, it’s the magnetic field”.   But what does that MEAN?  You might as well be saying “magical spirits.”  What is the EXACT mechanism by which the influence is mechanically transmitted.   That usually leads to “Well, it’s those lines of force.”

 

Sigh.  I’m either too dumb to ask the questions clearly or too dumb to understand the answer.

Is there an electro-magnetic-space/time plane of existence that is intersecting  the mass-space/time  plane that can be curved by magnetic potential instead of mass?  Would some kind of space curvature explain this invisible magnetic force the way it does gravitational force?

In a lot of ways magnetic fields are a lot freakier that gravitational fields.  Gravitational fields are continuous.  Magnetic fields are discontinuous, broken into the shells, or lines if you bisect them with a plane.  I can create magnetic fields at will with electricity.  Can you do that with gravity?  When I generate a magnetic field, am I warping electro-magnetic-space/time?

Yeah, I’ve always been fascinated my magnets and magnetism since I was a kid.
If you can explain it too me I’d be grateful.  But talk REAL slow and use small words. 

Regards,
Wab

[RufusLeaking]

Magnetic fields can repel as well as attract.

Where is my anti-gravity drive?

[CptTrips]

Magnetic fields can repel as well as attract.

Where is my anti-gravity drive?

Same with gravity I believe.  I think he said there was repulsive gravity.

Wab

[Seraphim]

You're not alone. I've felt the same way since I started studying science, and I've come to the conclusion that most scientists come up with theories & math to 'explain it', effectively confusing everyone else. Asking questions like yours puts them on the spot, which is always fun.
Kind of like having someone explain time.

I even heard someone come up with a formula that says it's possible for a body to randomly teleport instantaneously to Jupiter.

Yeah i see that happening.

[Simaril]

Congratulations to you, though. You have taken the step most people - even very, very smart people - never take. You're asking "HOW do we know that?" and "what is behind what you just said?" In my humble opinion, those are the kinds of questions that mark the beginning of true intellect.


In my somewhat limited experience, smart people function as if they were very highly trained technicians rather than real thinkers. They may have lots of knowledge in their field...but many folks just plod along well worn ruts. I'm a physician, and I've noticed that even my colleagues who know their fields remarkably well don't necessarily THINK about the data they've mastered, and the limitations of the studies on which they base their knowledge. And once they get outside their fields - well, a more cynical doctor than I calls physicians "highly trained technicians, but cultural barbarians."

That's a big part of why science in general advances by paradigm shifts rather than by accretion of knowledge - prior generations of scientists can't bring themselves to accept new ways of thinking, so the entire paradigm shift takes a generation (so the old guys can die off!) That concept comes from a book you'd probably enjoy, Thomas Kuhns' "The structure of scientific revolutions."



In my experience, the more one really knows and understands about knowledge, the more humble one becomes.

[Tac]

curved spacetime and 'the dip' in its fabric is what einstein describes with math but he did not figure out (or anyone yet) just what causes gravity in the first place.

The people messing with M theory were even throwing equations that gravity is a 12th dimension that intersects with our own via mass... and stated something that I found rather interesting:

It takes the mass of the entire planet earth to pull 1 unit of mass 'down' to the ground... yet the weakest magnet, the size of a penny will defeat gravity by pushing it up from the ground. Why is gravity so weak compared to a magnetic field?
 

[APDrone]

It takes the mass of the entire planet earth to pull 1 unit of mass 'down' to the ground... yet the weakest magnet, the size of a penny will defeat gravity by pushing it up from the ground. Why is gravity so weak compared to a magnetic field?
 

Well.... don't you think that if you were going to compare the strength of these forces, you'd compare their values at equal distances from their cores?  Isn't the force of gravity stronger the closer to the center of the mass you get?  

<edit> that's if you're comparing the strength of the tiny magnet to the gravity of the earth. 

If you're comparing the strength of the tiny magnet to the gravity of the tiny magnet, then one would conclude that magnetism is a stronger force than gravity.

[ghi]

 Maybe a  blind worm is asking himself "where is the heat coming from?" he can't see the Sun,  feels the effect only. Same with us, we have only the skin and 7 holes with  in our heads to  analyze the space around us, which i believe  is way  more than we can understand ,even with all the devices invented over past centuries.

[moot]

If you can explain it too me I’d be grateful.  But talk REAL slow and use small words.  

Gimme a coupla days.

Well.... don't you think that if you were going to compare the strength of these forces, you'd compare their values at equal distances from their cores?  Isn't the force of gravity stronger the closer to the center of the mass you get? 

<edit> that's if you're comparing the strength of the tiny magnet to the gravity of the earth. 

If you're comparing the strength of the tiny magnet to the gravity of the tiny magnet, then one would conclude that magnetism is a stronger force than gravity.

I think the apples to apples comparison he means is that for a single object of a certain mass, it takes a planet-size gravity field to attract it with a certain force, certain force which a penny-sized magnet can overcome with its "penny-sized" magnetic field.

Actual apples to apples between Earth and the magnet would require Earth to be downsized (not down-massed) to magnet's size. Otherwise the analogy breaks down (as you go towards center of Earth thru imaginary tunnel, gravity decreases due to mass being more and more around you instead of below you).

Cutting thru all the interpretation red tape, to the actual intended question - I don't remember the answer, but I remember learning it a while back.  So I'll go relearn it, and if someone doesn't beat me to it I'll explain it.

[lengro]

I’ve asked a lot of people, a lot smarter than me: “Yeah, but HOW does it transmit the force?  By what mechanism?“  The standard answer was “well uh, it’s the magnetic field”.   But what does that MEAN?  You might as well be saying “magical spirits.”  What is the EXACT mechanism by which the influence is mechanically transmitted.   That usually leads to “Well, it’s those lines of force.”

 

Yeah - we're in the same boat here - I've also thought about it for years, and never heard an answer. Science doesn't really know.

Curved spacetime describes the behavior of large scale objects extremely precise, but not how it actually works.
(Currently, scientist are not able to measure gravity on distances smaller than about 1/10 mm, so we can't observe if or how gravitational behaviour changes on small scale objects. If the behaviour changes, scientists believe that's a good indicator of extra (tiny) dimensions...)

I think particle physicists today would speculate something like:
there is no such thing as a complete vacuum. On a very small scale, space itself, is a random mess of small jitters and fluctuations (of something) - but on average it equals out, so it seems to be a vacuum. Put two bodies in this space, and they exchange some massless messenger particles called gravitons. Gravitons bounces between the bodies, and somehow this exchange makes the bodies move closer. The bigger mass affect more gravitons so it pulls the most. This cloud of gravitons, we observe as a field.

Not really an answer, eh?

One day I was babbling about spacetime and gravity to my 12y/o daughter (hey, she asked! ) - and told her how it bothered me not really knowing what gravity is. She thought about it for a moment and then said, that if 'they' figure it out after I'm dead - she would write the answer on my tombstone.

That eases the pain a bit.

[Melvin]

Start here.

http://www.geofex.com/Article_Folders/How_It_Works/hiw.htm

[lengro]

Start here.

http://www.geofex.com/Article_Folders/How_It_Works/hiw.htm

Basic electricity doesn't say anything about why gravity and electromagnetism works.

[bozon]

OK, I'll give it a shot:

"Forces" as we perceive them is something that causes acceleration. However, modern physics describe a force as something that changes momentum. The difference sound semantic and it is in classical physics, but not in relativity and quantum theories. Now comes the continuity, or the potential fields - Vacuum is not nothing. It is very much a something in physics: the space is filled with various "potential fields" that fluctuate. They actually what makes space and local variations is what we feel as forces.

Imagine potential fields as sheets of fabric that you can send waves through. The waves can travel in different directions across the sheet, but the sheet is there even if there are no waves on it. This could be your electric field for example. A charged particle will feel a force of the sheet around its location is not flat. A moving charge cases this sheet to wiggle and other particles will feel these wiggles as forces.

Gravity is described in slightly different terms, but also as a field. The puzzling thing about gravity is that mass have two jobs in physics: there is the kinematic mass which connects acceleration and force in classical physics (famous f=ma, and equivalent meaning in quantum physics between energy and momentum) and the "charge" of the gravitation force (in classic terms). Einstein's general relativity merges the two: there is actually no gravitation force in Einsteins theory. It describes mass (actually all energy) as the cause of bends in space itself. It gets quite complicated at this point, but the shape of space is curved by the presence of concentrated mass/energy and this curvature is translated into acceleration (hence, the classical force). There is still some dichotomy between this description of mass and the kinematic mass of quantum field theory, that describe it more in terms of a potential field (a scalar field where the fluctuations in it are called the Higgs particle, now being hunted in the CERN accelerator).

Magnetism is quite an amusing force, as it does not stand on its own. In classical physics (Maxwell's equations) it is an odd force that depends on speed instead of position and works in a perpendicular direction to the movement - this is more typical to "imaginary" forces in physics that arise due to changes in the frame of reference. Such an example is the Coriolis force in a rotating system that depends on the speed and operates perpendicular to the movement (it happens because the frame of reference is not at rest, but accelerating).
What Einstein showed in his "special relativity" is that the magnetic force can be described as a distorted electric field in a moving frame of reference (moving with respect to the frame in which there is only static electric field). This comes about if one assumes that the speed of light is constant in all frames of reference and immediately explained all 4 Maxwell equations as a simple static charge electric field being transformed into moving frame of reference. This is why it is normally referred to as the "electro-magnetic" force. Learning this is really one of the highlights of my undergrad physics studies, one of those moments that leaves you mouth opened, even before you get to the analytical and quantum mechanics stuff.

I hope I did not confuse you more...

[RTHolmes]

fields are only confusing if you keep hanging onto the idea of forces acting in a direct, connected way between objects. its a similar leap from considering 2 masses connected with a spring to 2 masses "connected" by gravity. they are different paradigms, you have to step back and look at each on its own merit, rather than trying to understand one from inside the other. reading Kuhn will help understand the whole paradigm thing, and that makes it much easier to skip from one paradigm to another.

another key thing to get used to is the idea that theories only give you answers to the questions you are asking - they are a bunch of tools in a toolbox, and you pull out the best tool for the job. they dont necessarily reveal the nature of reality, they just give you models to predict results. the only thing a theory "explains" is the theory itself.

quantum mechanics is the ultimate example of this - they are the most accurate theories science has (ie. predict experimental results to a degree of accuracy that no other theories do), but provide no explanation whatsoever of the nature of reality. there are several competing and incompatible interpretations of the theories, but it doesnt matter which interpretation you believe, you still use the same maths and you still get the same results.

[Melvin]

Basic electricity doesn't say anything about why gravity and electromagnetism works.

It is a building block.

Without a basic knowledge of electromagnetism, which is covered in the text, jumping into the "why" and "how" of electromagnetic energy's interaction with it's surroundings is like jumping into the deep end with concrete shoes.

I think bozon needs to expound on his last paragraph a bit more. There's some interesting stuff being discussed here.

Can the Aces High research lab figure it all out? I say we apply for a grant. You guys do the heavy thinking and I'll sweep the floors. Equal pay though.