How do magnets work? Seriously.

[hackenslash]

When something drops under gravity, it originally had POTENTIAL energy and that converts to the kinetic energy of the moving object.

That's a bit misleading, especially when we take General Relativity into account fully. The potential energy isn't something possessed inherently by the falling body, it's energy imparted by the gravitational field.

An example to illustrate:

Take two bodies of any mass. Choose examples in which one has mass significantly greater than the other. Also bear in mind that any body in an inertial frame has equal claim to being at rest. Set these two bodies apart such that the gravitational attraction between them is zero (not actually possible, since the range of gravity is infinite, but hey, this is a thought experiment). Now, their masses, and thus their energies, are fixed. Neither has potential in the gravitational field of the other. Move the larger of those two masses such that their gravitational fields begin to overlap, and they begin to gain potential energy. That energy wasn't there before, it was imparted by the gravitational field.

It's a very woolly thought experiment for several reasons. Firstly, the attraction between them is equal, which is to say that the gravitational field of each imparts potential energy on the other: When you throw a ball in the air, it isn't only the ball that receives potential energy, the earth does as well. Secondly, and as already stated, it's an unrealistic situation, because of the infinite range of gravity. Either way, it should serve to highlight the problem that many have with potential energy and how it works. Note that it doesn't make sense to say that either of them is actually moving. We don't have to impart motion to either of them, that was just for the sake of the experiment. In reality, this could occur where no motion was actually imparted to anything, because all motion is relative. If they were in an inertial field (not accelerated) the result would be the same.

There is never free energy. It either gets converted from one energy form to another, or comes from the conversion of mass to energy, as in e=mc2.

There are those who would argue, quite robustly, that there IS no energy.

Get out of that without moving.

[Pappa]

The thing that really bothers me is the "free" energy magnets seem to have. They can induce movement in other objects without seemingly expending any energy.

The energy has already been expended in aligning the innards of the magnet so that all of its whatsits are pointing in the same direction.

There is a total CHUNK of energy in an aligned whatsit - like fucking SHITLOADS! But pulling and pushing stuff around with the power of your innards causes them to slowly unalign - it might seem like a magnet just stays sticky FOREVAH - but it doesn't - it's just that the electromagnetic force is pretty damn HUGE compared to gravity (1036 times as MASSIVE!) and a little goes a long way. Stick an anvil to a magnet and dangle it - sooner or later the magneticisticism will run out and the anvil will fall directly onto the head of any passing coyote - but it will take a while - go have a cup of coffee and come back later... Magnetism can be preserved by inducing it with electrickery, or some shit, in which case, as long as you keep jamming volts into it, your anvil will hang there until the universe heat-death catches up with it - but energy free lunches only exist in fairy tales.

A while back on RDF, I asked the simple question, "Do magnets run out?". I was asking because I assumed what you just said was the case. This neatly explains how magnets exert a force, which has nothing to do with the kinetic energy used to move two magnets close together, and is nothing like gravitational potential energy either.
Unfortunately on RDF I was ridiculed and told flatly that, no, magnets don't run out. It was one of the reasons I stopped posting in the serious threads there.

Pappa, permanent magnets are like a spring. They don't "run out", they simply (when acting in pairs) store and release energy from outside their system...

OK, so if you were to create a magnet via electrical means, it would be able to exert a force at a distance forever? Where does the energy from outside its system originate?

[Pappa]

The thing that really bothers me is the "free" energy magnets seem to have. They can induce movement in other objects without seemingly expending any energy.

The energy has already been expended in aligning the innards of the magnet so that all of its whatsits are pointing in the same direction.

There is a total CHUNK of energy in an aligned whatsit - like fucking SHITLOADS! But pulling and pushing stuff around with the power of your innards causes them to slowly unalign - it might seem like a magnet just stays sticky FOREVAH - but it doesn't - it's just that the electromagnetic force is pretty damn HUGE compared to gravity (1036 times as MASSIVE!) and a little goes a long way. Stick an anvil to a magnet and dangle it - sooner or later the magneticisticism will run out and the anvil will fall directly onto the head of any passing coyote - but it will take a while - go have a cup of coffee and come back later... Magnetism can be preserved by inducing it with electrickery, or some shit, in which case, as long as you keep jamming volts into it, your anvil will hang there until the universe heat-death catches up with it - but energy free lunches only exist in fairy tales.

A while back on RDF, I asked the simple question, "Do magnets run out?". I was asking because I assumed what you just said was the case. This neatly explains how magnets exert a force, which has nothing to do with the kinetic energy used to move two magnets close together, and is nothing like gravitational potential energy either.
Unfortunately on RDF I was ridiculed and told flatly that, no, magnets don't run out. It was one of the reasons I stopped posting in the serious threads there.

Pappa, permanent magnets are like a spring. They don't "run out", they simply (when acting in pairs) store and release energy from outside their system...

OK, so if you were to create a magnet via electrical means, it would be able to exert a force at a distance forever? Where does the energy from outside its system originate?

I think I'm slowly starting to understand.... this helped a bit:

Regarding the use of the word "energy". Energy is the same thing as work. Work = Force x distance. If there is a 10N [Newton] force acting on a ball, and you move the ball by 1m [meter], you have done 10N x 1M = 10Nn = 10J [Joule] of work (provided the force is constant). So, if you move the magnetic poles against each other, you do work (against the EM field). Then, if you attach the magnets to a spring and let go, the springs will compress. The 10J of work you invested is now stored in the springs! Then, if you remove the magnets and put a bullet on the spring, and let go, you can use the 10J of energy to launch the bullet (work is converted to kinetic energy), and so on =)

[cronus]

Solid iron based magnets do degrade with usage. Their little domains that build up the larger magnetic field get nudged out of skew and the field weakens with each knock the magnet takes.

[surreptitious57]

There are those who would argue quite robustly that there IS no energy

The positive energy of matter is supposed to cancel out the negative energy of gravity. Though if that is true then why is the Universe constantly expanding ? Reason
for that is because of dark energy. As the expansion has been ongoing since Planck time then the net energy of the Universe has never been at zero. Einstein thought
it was which is why he referenced his famous cosmological constant. But now it is actually regarded as being true because it accounts for dark energy. Though this is
misleading because Einstein did not know of the existence of dark energy. The fact his constant can prove something else is mere coincidence for he was still wrong
He said it was the single biggest mistake of his life. Actually that is wrong also for his single biggest mistake was denying quantum mechanics because it was counter intuitive. However if counter intuition is incompatible with observed phenomena then it is wrong no matter how incomprehensible it appears. Even if the one being
counter intuitive happens to be Einstein. What is objectively true must always be accepted as long as it is capable of being subject to falsification. Though it should
be pointed out that falsification is not automatically an indicator of truth. Rather the most reliable model that there is based upon existing knowledge [ wink wink ]

[cronus]

Energy is a very human-centric notion. I doubt it is very likely to help in a precise and accurate description of the cosmos at large. I'd like to abandon terms that can be related to human experience when describing the universe. If biology can achieve this with genetics and still be a massively informative discipline then it should be possible with physics and its numerous observations. And that way something progressive might come with regards unifying the large and small systems approach to the universe?

[hackenslash]

Energy is a very human-centric notion. I doubt it is very likely to help in a precise and accurate description of the cosmos at large. I'd like to abandon terms that can be related to human experience when describing the universe. If biology can achieve this with genetics and still be a massively informative discipline then it should be possible with physics and its numerous observations. And that way something progressive might come with regards unifying the large and small systems approach to the universe?

It's actually quite a robust concept, and extremely useful, but incredibly well-understood, at least by physicists.

I was tempted earlier to slightly critique the section Pappa found helpful, but decided not to, because I didn't want to muddy the waters and because it was only minor niggles I had with it, largely centred around the language.

Energy is the ability to perform work, rather than being equivalent to work, work is the application of force, and force is the equalisation of differentials.

That was all, really.

[hackenslash]

The positive energy of matter is supposed to cancel out the negative energy of gravity. Though if that is true then why is the Universe constantly expanding ? Reason for that is because of dark energy. As the expansion has been ongoing since Planck time then the net energy of the Universe has never been at zero.

That's not correct. Certainly we have to account for dark energy, but given the very real possibility that it's simply gravity, it won't actually affect the outcome. The expansion of the universe is actually irrelevant, because we'd have every reason to expect the universe to be expanding still without the inclusion of dark energy. That's why it was such a surprise to find that expansion has been accelerating for about the last 4 billion years. Further, the accounting isn't remotely complete as yet, as we haven't accounted for all the mass of the universe beyond some broad-brush calculations, some of which are based on expectation, rather than via experiment. We know how much we can see, but we haven't remotely accounted for that which we can't. It's not remotely beyond the realm of possibility that dark matter is actually generated by dark energy, which would go some way toward balancing the books, as it were. The zero-energy hypothesis is only a hypothesis at this point, though not an unreasonable one. If you look at the way I defined the terms in my response to Scumple, we can think of the universe as one giant differential, continually being created. Thinking about entropy in this framework is useful as well, because the expansion changes the game entirely, driving the net value for maximal entropy up and up as it expands.

[quote Einstein thought it was which is why he referenced his famous cosmological constant. But now it is actually regarded as being true because it accounts for dark energy. Though this is misleading because Einstein did not know of the existence of dark energy.[/quote]

Yes, as I've said before, a fair bit of bollocks is spoken about the cosmological constant. Einstein had it right, it was a massive blunder. That the term he fudged into his equations happens now to be useful has no impact on Einstein getting it horribly wrong. The only reason it turns out to be useful is that it was a term inserted into the equations that allowed the universe to exist in a steady state. Because it works to stop expansion or contraction, giving it a different value can either accelerate expansion (positive value) or generate contraction (negative value). Einstein had it as a constant, which it can't be.

The fact his constant can prove something else is mere coincidence for he was still wrong He said it was the single biggest mistake of his life. Actually that is wrong also for his single biggest mistake was denying quantum mechanics because it was counter intuitive.

Indeed, although it wasn't really because it was counter-intuitive but because it was probabilistic, and he was a determinist in the full Laplacian sense, hence the famous comment about dice.

However if counter intuition is incompatible with observed phenomena then it is wrong no matter how incomprehensible it appears. Even if the one being counter intuitive happens to be Einstein. What is objectively true must always be accepted as long as it is capable of being subject to falsification. Though it should be pointed out that falsification is not automatically an indicator of truth. Rather the most reliable model that there is based upon existing knowledge [ wink wink ]

Yup.

[Tero]

Atoms. Everything is atoms, or stuff that fell out of them. Little magnets live inside some atoms. Not all. You have to play the video game to figure out which ones.

Electrons can be unhappy alone. They become juvenile delinquents and carry switchblades. Wiki explains:

However, in materials with a filled electron shell, the total dipole moment of the electrons is zero because the spins are in up/down pairs. Only atoms with partially filled shells (i.e., unpaired spins) can have a net magnetic moment, so ferromagnetism only occurs in materials with partially filled shells. Because of Hund's rules, the first few electrons in a shell tend to have the same spin, thereby increasing the total dipole moment.

[surreptitious57]

If dark energy did not exist then why would the Universe still be expanding ? How is it possible to accurately measure its mass when it is not static ? One could measure the distance of the furthest star by how long it tales light to reach Earth but expansion means that that figure would not be accurate beyond the time of measurement Where did the energy that caused the quantum leap of the Big Bang originally come from ? A singularity is a point so dense that time can not exist beyond it but if that
is true then why does inflation theory support an eternal Universe ? Is the answer that this Universe began at the Big Bang and the energy came from another ? Though that does not explain where it originally came from. One cannot use the First Law Of Thermodynamics here because what applies to within a system does not apply to
the system itself. And how can a multiverse hypothesis be falsified if light is impervious to branes ? [ may have asked some of these before and so apologies if I have ]

[hackenslash]

If dark energy did not exist then why would the Universe still be expanding ?

Just from the initial expansion. We knew from observation that it was still expanding from Hubble's work in the 20s and 30s, and there was no reason to suppose that it wouldn't be, although it was expected to be slowing down due to gravitational attraction of all the matter and dark matter (dark matter was postulated not long after the Hubble observations based on the orbits of stars in the outer edges of galaxies, especially small galaxies). When it was observed in 1998 that expansion was accelerating, the research that revealed it was actually geared to finding out how much expansion was slowing. I remember the announcement like it was yesterday. I was gobsmacked.

How is it possible to accurately measure its mass when it is not static ?

Some of it is extrapolation from such things as overall energy density, which is isotropic and homogeneous as far as can be ascertained. That it isn't static isn't actually relevant.

One could measure the distance of the furthest star by how long it tales light to reach Earth but expansion means that that figure would not be accurate beyond the time of measurement

It doesn't matter, not least because we can measure red shift, which is also a measure of distance on the largest scale, due to Hubble's law.

I know you've seen the Krauss lecture, so you'll remember the diagram with the square of dots showing how expansion is the same in all directions, regardless of where you are. Another feature of that is that it shows how there is a direct relationship between how far away something is and how quickly it's receding from us. What this means is that we can measure how fast something is receding and directly assess how far away it is by its rate of recession.

Where did the energy that caused the quantum leap of the Big Bang originally come from ?

It didn't have to come from anywhere if there is no energy. Either way, it's the wrong kind of question. Since this has come up, and since I've been meaning for a while to type this up and add it to my clippings library, here's Brian Greene:

Quantum mechanics is a conceptual framework for understanding the microscopic properties of the universe. And just as special relativity and general relativity require dramatic changes in our worldview when things are moving very quickly or when they are very massive, quantum mechanics reveals that the universe has equally if not more startling properties when examined on atomic and subatomic distance scales. In 1965, Richard Feynman, one of the greatest practitioners of quantum mechanics, wrote:

"There was a time when the papers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when one man did because he was the only guy that caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in one way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics"

Although Feynman expressed this view more than three decades ago, it applies equally well today. What he meant is that although the special and general theories of relativity require a drastic revision of previous ways of seeing the world, when one fully accepts the basic principles underlying them, the new and unfamiliar implications for space and time follow directly from careful logical reasoning. If you ponder the descriptions of Einstein's work in the preceding two chapters with adequate intensity, you will - if even for just a moment - recognize the inevitability of the conclusions we have drawn. Quantum mechanics is different. By 1928 or so, many of the mathematical formulas and rules of quantum mechanics has been put in place and, ever since, it has been used to make the most precise and successful numerical predictions in the history of science. But in a real sense those who use quantum mechanics find themselves following rules and formulas laid down by the "founding fathers" of the theory - calculational procedures that are straightforward to carry out - without any real understanding why the procedures work or what they really mean. Unlike relativity, few if any people ever grasp quantum mechanics at a "soulful" level.

What are we to make of this? Does it mean that on a microscopic level the universe operates in ways so obscure and unfamiliar that the human mind, evolved over eons to cope with phenomena on familiar everyday scales, is unable to fully grasp "what really goes on"? Or, might it be that through historical accident physicists have constructed an extremely awkward formulation of quantum mechanics that, although quantitatively successful, obfuscates the true nature of reality? No one knows. Maybe some time in the future some clever person will see clear to a new formulation that will fully reveal the "whys" and the "whats" of quantum mechanics. And then again, maybe not. The only thing we know with certainty is that quantum mechanics absolutely and unequivocally shows us that a number of basic concepts essential to our understanding of the familiar everyday world fail to have any meaning when our focus narrows to the microscopic realm. As a result, we must significantly modify both our language and our reasoning when attempting to understand and explain the universe on atomic and subatomic scales.

The Elegant Universe - Greene 1999

Now, if the universe arose via a quantum fluctuation, the idea of 'where it came from' is precisely one of those things that fails to have any meaning, and that actually includes the idea that it needs to come from anywhere. The further problem with it is, of course, that 'where' refers to a location in space, and there wasn't any.

Either way, if the quantum fluctuation hypothesis is correct, it only requires the uncertainty principle to address this. A rare statistical anomaly will suffice. It's only needed to be sufficiently large for inflation/expansion to take over. Under normal circumstances, such a fluctuation would be extremely short-lived (hence 'virtual' particles) but, given a sufficiently large fluctuation, expansion could take over and result in the universe we see today.

A singularity is a point so dense that time can not exist beyond it but if that is true then why does inflation theory support an eternal Universe ?

Well, inflationary theory comes in several flavours. Eternal inflation (the eternal universe version of inflationary theory) doesn't involve singularities in the conventional sense. You might think of each universe arising as a black hole in another universe, which may involve other dimensions. Our universe would, therefore, be a singularity in another cosmic expanse, because from the perspective of that cosmic expanse, our universe appears as a singularity (more on this in a mo), but it has extended dimensions in ours.

I should note once again that a singularity is actually problematic in quantum mechanics, depending on what you mean when you say 'singularity'. In general scientific parlance, a singularity is simply an event that our theories can't describe or, loosely, something that causes them to break. In a certain cosmological context, it means a region of infinite density and curvature. I've already discussed with you elsewhere the problems faced with the singularity but, since those discussion were elsewhere, I'll summarise the issues here: The physical singularity arises from a treatment of the reversal of cosmic expansion rooted entirely in General Relativity. General Relativity has no problem with this event, except that it can't describe anything on those scales. Further, Quantum Mechanics suggests that the physical singularity is actually asymptotic. so it can be approached but never reached. Either way, it presents problems.

Further, the singularity, even could it exist, isn't actually an event beyond which time cannot exist, it's simply an event that cannot experience time, due to the extreme gravitational time dilation at such densities of mass. That doesn't mean there was no time before the singularity, only that the singularity wasn't subject to it.

Is the answer that this Universe began at the Big Bang and the energy came from another ?

Could be. It might simply be that the energy input to our cosmos was simply the implosion of an extremely large star. That has implications for precisely what kind of thermodynamic system we're in, of course. If your cosmos is a black hole in another expanse, then new mass/energy could be input simply by the accretion of mass/energy in the black hole in the parent system, meaning that our cosmos is not an isolated system, but actually an open one, rendering the 1LT entirely moot! That's one of the reasons I warn against erecting thermodynamic arguments regarding the instantiation of the cosmos except in response to thermodynamic arguments regarding the instantiation of the cosmos.

Though that does not explain where it originally came from.

Covered above.

One cannot use the First Law Of Thermodynamics here because what applies to within a system does not apply to the system itself.

Have a care here. I've given a reason why the 1LT shouldn't be used (two reasons, actually), but you have to be really careful how you apply this. It is certainly true that it's fallacious to insist that what applies within a system applies to the system itself (fallacy of composition), but it's equally fallacious to insist that it doesn't. This is a slightly different fallacy, the fallacist's fallacy, which is committed when a conclusion is rejected on the basis that the reasoning behind it is fallacious. The conclusion could still be true, regardless of the reasoning.

And how can a multiverse hypothesis be falsified if light is impervious to branes ?

Well, it looks like we can forget branes, assuming the B Mode polarisation observations are confirmed, so a moot point. In this case, we've just seen our very first observations employing gravity rather than electromagnetism. If this sort of gravity detection can be refined, it might be that we can see back to the Planck time and even beyond it. All we need to do is to work hard on the observations, formulate hypotheses with regard to what those observations might mean, develop predictions rooted in what we might observe if our cosmos is a black hole in another cosmos and, voila!

[ may have asked some of these before and so apologies if I have ]

No worries. I don't think I've covered much of this ground here and, aside from loving the look of my own text, there are those here who might well be interested or provide critique or clarification, or indeed correct some of my own misconceptions regarding this material and the various hypotheses pertaining thereto.

My only problem is your propensity for driving such long posts from me in response, given that I've had to sit up for this, and it's still quite early in my recovery process fro the spinal surgery, meaning that I shouldn't sit up for too long.

That was a joke, by the way, except that I am in a bit of pain now.

Anyhoo, always my pleasure, you know that.

[FBM]

Feynman didn't help much.

Depends. It's significant to note how why-questions tend to multiply exponentially the more precisely or thoroughly you try to answer them. For example, hack gave an excellent answer above, but you can still come up with a handful of why-questions for every sentence he posted. Fortunately, the OP is a how-question, so hack's answer is satisfying.

[hackenslash]

Feynman was a diva, and I miss him greatly.

[surreptitious57]

I thought you were on the way to a full recovery because you have said nothing about it since getting home. I shall not ask any more questions therefore because in spite of your little joke it would not be right to impose them on you. You could of course not answer them but I would still feel guilty about asking them since that would still not be right. I did wonder why you were only posting one liners for a while. I thought you were thinking of leaving because it was no longer interesting. I know you have subsequently said that is not an option because of the time and energy you have put in but I did not know at the time. I do not want to sound like your mother but you really should not be doing anything that is aggravating your recovery. So try to keep away from the net now while you are getting better and please do not answer this otherwise I might give you a bollocking which will only make me feel guilty. So please take the drugs and go to sleep and do not come back till you are fully recovered

[hackenslash]

Actually, today is the first day with no pain relief (although I'm about to drop a couple of tramadol before going to bed). Recovery is moving apace, but I've exerted myself a bit today, having posted a few long posts (that response to CharlieM took fucking ages, transcribing the Ken Miller video manually) and gone for a 1/4 mile walk.

I've just maybe overdone it a bit, and now I'm feeling it. It's all good, and I'm well on the mend.