Basic Question about Atoms

[yukoncpa]

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Empty space is nothing like nothing.

Empty space is really something.



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Yes, but like Metric said, empty space is made up of fields. What exactly is a field? What is a magnetic field or a gravitational field? What are these things made of? How and where do they exist? If I’m understanding things correctly, there is no explanation.

[ChrisV]

Fields are just an abstraction. Forces are actually carried by particles - photons in the case of electromagnetic forces, W and Z bosons in the case of the weak nuclear force, and gluons in the case of the strong nuclear force. According to relativity, gravity is different and is the warping of spacetime. Metric's quote is related to quantum theories of gravity, which are untested and unproven. Quantum gravity theory treats gravity as another quantum field with the force mediated by as yet undetected particles called gravitons. I don't know how this is supposed to merge with the other proven results of relativity, for example time dilation.

[yukoncpa]

[ QUOTE ]
Fields are just an abstraction. Forces are actually carried by particles - photons in the case of electromagnetic forces, W and Z bosons in the case of the weak nuclear force, and gluons in the case of the strong nuclear force. According to relativity, gravity is different and is the warping of spacetime. Metric's quote is related to quantum theories of gravity, which are untested and unproven. Quantum gravity theory treats gravity as another quantum field with the force mediated by as yet undetected particles called gravitons. I don't know how this is supposed to merge with the other proven results of relativity, for example time dilation.



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Hi, thank you, I wasn't aware that forces of electromagnetism were understood. Show's my primitive understanding of physics. I guess I just don't understand how photons hold things up or attract and repel things or how boson's and gluons work.

[Metric]

[ QUOTE ]
Fields are just an abstraction. Forces are actually carried by particles - photons in the case of electromagnetic forces, W and Z bosons in the case of the weak nuclear force, and gluons in the case of the strong nuclear force. According to relativity, gravity is different and is the warping of spacetime. Metric's quote is related to quantum theories of gravity, which are untested and unproven. Quantum gravity theory treats gravity as another quantum field with the force mediated by as yet undetected particles called gravitons. I don't know how this is supposed to merge with the other proven results of relativity, for example time dilation.

[/ QUOTE ]
Perhaps I don't need to be a nit here and confuse people any further, but "particles" are really just individual excitations of fields. This "particle interpretation" only works if spacetime has certain symmetries, such as those that exist if spacetime is flat -- if spacetime happens to be curved in an ugly way, you can lose the particle interpretation entirely, while the concept of a field is still valid.

As for what a field "really is" -- well, it's a mathematical structure that behaves like what we observe. There may or may not be something more fundamental, which will also just be a piece of mathematics that behaves like what we observe.

[arahant]

[ QUOTE ]
[ QUOTE ]
Fields are just an abstraction. Forces are actually carried by particles - photons in the case of electromagnetic forces, W and Z bosons in the case of the weak nuclear force, and gluons in the case of the strong nuclear force. According to relativity, gravity is different and is the warping of spacetime. Metric's quote is related to quantum theories of gravity, which are untested and unproven. Quantum gravity theory treats gravity as another quantum field with the force mediated by as yet undetected particles called gravitons. I don't know how this is supposed to merge with the other proven results of relativity, for example time dilation.

[/ QUOTE ]
Perhaps I don't need to be a nit here and confuse people any further, but "particles" are really just individual excitations of fields. This "particle interpretation" only works if spacetime has certain symmetries, such as those that exist if spacetime is flat -- if spacetime happens to be curved in an ugly way, you can lose the particle interpretation entirely, while the concept of a field is still valid.

As for what a field "really is" -- well, it's a mathematical structure that behaves like what we observe. There may or may not be something more fundamental, which will also just be a piece of mathematics that behaves like what we observe.

[/ QUOTE ]

That sounds vaguely like bunk, but I'll save that for a nenw, and sober, thread.

My (possibly digressive) question is this:

How much energy is there in say, ME, versus the gas that surrounds me. I did a little googling earlier, and couldn't really figure it out. It looks like there is still a great deal of ambiguity around 'zero-point energy' for the vaccuum, etc...

This is inspired by a concept one often hears in Buddhism ('what am I' being one phrasing). I've always assumed that the density of "me" is significantly greater than the density of my surroundings, in some clear and absolute sense, and that there is therefore a reasonable definition of 'me'....Ok, I'm drunk (but up about 1k live), so I may just need to start a new thread tomorrow....but if you can make sense of this, help me out a bit [img]/images/graemlins/wink.gif[/img].

[Metric]

E(you + vacuum) - E(vacuum) = mass of you times c^2

The energy of the vacuum itself is not known -- only the energy difference associated with your existence is known, which is the right hand side of the equation.