Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: yor_on on 14/03/2012 16:20:06
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Myself I think of it as something expressing itself in 'transformations' as interactions. But consider a gravitational wave. It will have both a 'energy' and a 'mass' of its own as it 'moves'. In the same time as it is a geometrical propagating displacement of SpaceTime.
So, what would you define 'energy' as?
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Energy is the fundamental stuff from which the the universe is built. It is probably best described as the ability to create action. Action as a physical term is not often used but Planck's constant is a measure of it. It can be thought of as moving some object against the opposition of a force. Alternatively it can be released by something moving in an attractive force. This movement has to have a direction and when you add direction to movement you get momentum the other fundamental component of our universe. Mass is a trapped energy in the form of particles that can interact according to the energy that they have.
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So, 'transformations' and 'creating action'?
Thanks SoulSurfer.
What more descriptions are possible?
Is energy a 'field' for example?
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A measure of all aspects of String vibration, like amplitude, frequency, presence in how many and which dimensions,.... ?
And by expansion, not only strings, but also branes and higher order structures...
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'strings' and 'branes' as energy?
I'm not sure of that one Nizzle, maybe? But a 'string' 'loop' etc is under an enormous tension, and that tension is also a 'energy'
As for a 'brane'? I don't know at all. There you will have to convince me
But 'tension' I can accept :) and it's equivalence 'pressure'.
So 'energy' could be expressed as 'transformations' , 'creating action' and 'tension / pressure'
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Any more suggestions?
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Good answer by Soul Surfer.
If you consider the Universe to be 'clockwork' then entropy is the 'restoring force' that is stored in the spring. Entropy uses energy.
Entropy is a restoring 'force'. The more energy you put into something, the greater the restoring force. When a 'mechanism or process' uses energy that mechanism or process reaches a more stable state as the entropy of the system increases.
Polite replies on a postcard please to... :)
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Energy is the substance of the universe that can be observed in space and time.
Where is the gravitational energy? Distance and timerate between elementary particles. Same for electromagnetic energy...
Distance can be reduced to time by the speed of light!
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I just asked a similar question to this. My Idea is that energy is purely information a particle could be sat infront of your nose and in an instant fly off in any direction at whatever required speed all it needs is the information which it gets from interaction with another partical.
I may be talking rubbish though i have had a few sipps of the thinking juice tonight lol
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Space-time is probably an emergent property of energy exploring all the possibilities that can exist in an undefined number of dimensions and finding that some create persistent and more probable properties that result in particles and fields like gravity.
The best image that I can think of are multidimensional vortexes of various shapes. The fundamental constant appears to be what we call the speed of light but talking about a speed implies that what we call time and space are already there and it is very difficult to visualise a situation where time and space are totally malleable.
The uncertainty relationships between energy and momentum effectively create a "box" within which there exists nothing but probabilities that eventually define what appears out of the box.
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String "theory" strikes me as being pretty hard to argue with. (Theory in quotes 'cos it is not exactly a theory - yet.)
Energy and mass have equivalence, but when you look at matter, there's almost nothing there! Consequently, it's a bit difficult to come to any other conclusion than that the energy is somehow "stored" within spacetime itself, and matter is only a sort of wrapper for that containment.
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Space-time is probably an emergent property of energy exploring all the possibilities that can exist in an undefined number of dimensions and finding that some create persistent and more probable properties that result in particles and fields like gravity.
The best image that I can think of are multidimensional vortexes of various shapes. The fundamental constant appears to be what we call the speed of light but talking about a speed implies that what we call time and space are already there and it is very difficult to visualise a situation where time and space are totally malleable.
The uncertainty relationships between energy and momentum effectively create a "box" within which there exists nothing but probabilities that eventually define what appears out of the box.
Again I think that is a good answer from Soul Surfer.
That is something I have advocated for a long time. I would add matter to the equasion but as matter is energy then it is still correct to just mention energy.
String "theory" strikes me as being pretty hard to argue with. (Theory in quotes 'cos it is not exactly a theory - yet.)
Energy and mass have equivalence, but when you look at matter, there's almost nothing there! Consequently, it's a bit difficult to come to any other conclusion than that the energy is somehow "stored" within spacetime itself, and matter is only a sort of wrapper for that containment.
True.
Energy is stored within space-time by gravity (the warping of space-time) and by the nuclear forces that bind electrons, neutrons and protons into atoms and the molecular forces that bind atoms to each other. All can be used as a source of energy.
It's all about systems trying to reach their most stable state which is accomplished when there is a reduction of usable energy. In other words it's all about entropy.
I think this link helps to put it into context.
http://www.furryelephant.com/content/radioactivity/nuclear-stability-fusion-fission/
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Energy is stored within space-time by gravity
Can you prove that, or is it supposition?
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Energy is stored within space-time by gravity
Can you prove that, or is it supposition?
yor_on and I have already had that discussion in another thread.
A ball thrown onto a ledge stores the kinetic energy that it took to throw it onto the ledge as 'gravitational potential energy'. That is energy stored within space-time by gravity.
Proof enough?
Another example.
For two (initially 'stationary') massive objects in space to gravitionally combine it obviously requires an input of energy to make this happen. Where does the energy come from? When the two objects combine, time for them as a pair passes slower (time dilates) than it did for them individually. This is equivalent to a reduction in useful energy. The energy was stored in space-time by gravity.
Gravity, the strong nuclear force and the molecular force are all 'restoring' forces. They store energy in much the same way as a spring.
Perhaps I should say that gravity acts the same as a restoring 'force' as I am sure someone (a particularly vigilant moderator) will point out that gravity is not actually a force.
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"The fundamental constant appears to be what we call the speed of light but talking about a speed implies that what we call time and space are already there and it is very difficult to visualise a situation where time and space are totally malleable."
True SoulSurfer.
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The fabric of spacetime cannot explain the spin entanglement. Entanglement seems to show that their is an absolute instantaneity. Spacetime emerging from energy implies a beginning. Ultimately, how is it possible to explain that there was a beginning?... A beginning from nothing? No way!!!
Eternity may be unimaginable but it is not impossible... ;)
General relativity is right but it has its limits...
You can view space as a pure 3D vacuum (simple Euclidean 3 dimensions) and effective distance and timerate as Einstein's spacetime (though it is an incomplete model for very small distances).
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We better be clear on one thing, ahem. Exchanging a expression as 'energy' for, let's say :) 'information' or 'entropy' does not make it clearer to me. We just change the very word describing it, if so.
But finding expressions/definitions that describes, rings in, what 'energy', 'entropy', 'information' actually does do help.
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Energy can only be exchanged locally but not necessarily information as 2 spin entangled particles stay entangled as long as there is no exchange of energy of the spin of one of the two particles with a third one locally... The spin entanglement seems to be quantized not only in its absolute value but in terms of changes in angle vs energy exchange too. Relative timerate is in the particle rest energy vs its relative size and it is directional.
Euclidean space means preferred directions in the universe. Recent observations tend to show exactly that but people keep trying to find a solution in Minkowski spacetime... Beyond that it should belong to new theory section... :)
http://www.dailygalaxy.com/my_weblog/2012/03/is-our-solar-system-a-region-of-the-universe-just-right-for-life.html#more
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d/e/f= doit/e/fkit
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I would define energy like this
http://home.comcast.net/~peter.m.brown/mech/what_is_energy.htm
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Energy is a lot like money. It moves around, and if you are clever, you can get it to do something useful for you in the process. You might even call it "The currency of the Universe".
Unfortunately, the Universe is also a Taxation Authority, and every time energy does move around, the Universe demands a piece of the action. It seems that, eventually, the tax will even everything out, at which point the Taxation Authority will be out of business because it has nothing left to tax.
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'strings' and 'branes' as energy?
I'm not sure of that one Nizzle, maybe? But a 'string' 'loop' etc is under an enormous tension, and that tension is also a 'energy'
As for a 'brane'? I don't know at all. There you will have to convince me
But 'tension' I can accept :) and it's equivalence 'pressure'.
So 'energy' could be expressed as 'transformations' , 'creating action' and 'tension / pressure'
Oh don't count on me to explain. I don't even believe in String theory, just read some books about it, but I was curious about the reactions..
I'm a supporter of the photon-only universe..
For me, energy is simply an EM-field fluctuation.
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Geezer
Good analogy.
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Energy is animal,which eats time and creates motion or gravitation.Gravitational waves turn back gradually into time after long way in space. :)
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I thought Energy was defined as the potential for work, therefore energy is little pink fluffy creatures that exist in another dimension and all they do in our dimension is work. Prove me wrong, haha.....
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I thought Energy was defined as the potential for work, therefore energy is little pink fluffy creatures that exist in another dimension and all they do in our dimension is work. Prove me wrong, haha.....
Can you make work without meal?Can energy make work without feed of time?Identically. :P
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Can you make work without meal?Can energy make work without feed of time?Identically. :P
I gonna go for YES :) If space is time, and the big bang created it, then what did the work, to feed time, without a meal!?
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The best definitions are those that rings in what it do, and also can describe the mechanism by which we see it happen. There I have no notion of little pink fluffy creatures?
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There I have no notion of little pink fluffy creatures?
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fimg694.imageshack.us%2Fimg694%2F4744%2Fpinksheepatsheepworld.jpg&hash=ca628aa98cb414ab58e2f8d4557aff75)
You mean these? They're pretty lazy, so I don't think they do much work.
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Of course, every family has its blue sheep.
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Can you make work without meal?Can energy make work without feed of time?Identically. :P
I gonna go for YES :) If space is time, and the big bang created it, then what did the work, to feed time, without a meal!?
Space is not time.The collision of time star and energy star caused the big bang.
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Can you make work without meal?Can energy make work without feed of time?Identically. :P
I gonna go for YES :) If space is time, and the big bang created it, then what did the work, to feed time, without a meal!?
Space is not time.The collision of time star and energy star caused the big bang.
You're right regarding space and time. Laymen seem to confuse it more than any other concept in relativity. Mathematically they are treated on the same footing to a certain extent. But they are quite different concepts physically - So said Einstein.
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I thought energy was just existence. :(!
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Energy is Nature's Currency, like Geezer already hinted at by comparing it to money.
And black holes are like governments and banks.
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Energy is more like money than you think because you can borrow it to do something but you have to pay it back within a precisely defined time. The more you borrow the quicker you have to pay it back. Planck's constant is what tells you how quickly you need to pay it back and the uncertainty principle is the results of this borrowing process.
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Surfer - I agree but I would say this borrowing process is the result of the uncertainty principle rather than the other way around. The physical interpretation of the maths is open - but the maths is clear, if properties are presented in infinite matrix form (via fourier transforms) then the non-commutative nature of those matrices will require an uncertainty.
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Energy is more like money than you think because you can borrow it to do something but you have to pay it back within a precisely defined time. The more you borrow the quicker you have to pay it back. Planck's constant is what tells you how quickly you need to pay it back and the uncertainty principle is the results of this borrowing process.
I disagree. If you think of energy simply as something that is merely conserved then you have to explain why momentum isn't energy. Also that is not what Planck said about energy. That expresssion for time-energy does nor mean that time isn't always conserved. It's unfortunate that so many people think that it is. However David Griffiths teaches differently in his QM text. I wrote out his derivation here.
http://home.comcast.net/~peter.m.brown/qm/time_energy_hup.htm
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Energy is more like money than you think because you can borrow it to do something but you have to pay it back within a precisely defined time. The more you borrow the quicker you have to pay it back. Planck's constant is what tells you how quickly you need to pay it back and the uncertainty principle is the results of this borrowing process.
I disagree. If you think of energy simply as something that is merely conserved then you have to explain why momentum isn't energy. Also that is not what Planck said about energy. That expresssion for time-energy does nor mean that time isn't always conserved. It's unfortunate that so many people think that it is. However David Griffiths teaches differently in his QM text. I wrote out his derivation here.
http://home.comcast.net/~peter.m.brown/qm/time_energy_hup.htm
Peter - nicely written out and explained. Still not sure I agree (to be honest I don't understand yet) - and waiting to see what SoulSurfer say.
One quick point - on your first equation, I am thinking that an i is needed on rhs, or have i got wrong end of stick.
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One quick point - on your first equation, I am thinking that an i is needed on rhs, or have i got wrong end of stick.
I don't understand what you mean. Can you clarify. By the way, I never posted a derivation of Eq. (1) and I really should.
Best wishes,
Pete
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It all depend on how you see it. If you want a arrow that is 'the exact same' there is only the local reference frames you can use. Then that 'locality' is what is proven to be the 'exact same'. Any experiment that moves its 'clock' to where the observed 'time rate' discrepancy first was noticed will find both 'clocks to sync again.
So, assuming we could super impose those 'clocks', which we in theory can as the best clocks are radiation we have a locally 'same' exact arrow, if we go by 'clocks'. And then the best clock will be the clock that defines the arrow, 'c'.
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I feel that you may be talking at cross purposes and seeing slightly different features because you are coming at the concept from different directions.
Remember the HUP is frequently expressed as a position-momentum relationship and/or a time-energy relationship. The basic dimensions of Planck's constant are that of Action (a term not much used nowadays)
Planck’s constant = 6.626068 x 10-34 metres x kilogram x metres/second
distance x mass x velocity
i.e. distance travelled and momentum
Planck’s constant = 6.626068 x 10-34 kilogram . (metres/second)2 . Seconds
mass times velocity squared x time period
Kinetic energy x time
So you are looking at a multidimensional uncertainty that covers all relevant dimensions taken together. Those are only two planes through a larger figure
I see it as a sort of "noise level" in the universe.
One of my fundamental questions that I tend to put up on blackboards in my thinking and working areas is the value and dimensions of Planck's constant followed by the word Why?
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Yeah, constants is the big mystery here. Why do they exist, and what defines them?