The Naked Scientists

The Naked Scientists Forum

Author Topic: Is the total energy in the Universe conserved?  (Read 17055 times)

Offline chiralSPO

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1872
  • Thanked: 143 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #25 on: 29/10/2014 17:40:29 »
My understanding of the "negative energy" phenomenon of gravity is something along these lines:

Imagine two photons of sufficiently high energy interact to produce an electron positron pair in some hypothetical otherwise empty universe. We can calculate the amount of energy the photons need to have for this to happen.

Now imagine the same reaction occurs very near to a massive object (in a large gravitational field). The energy required for this to happen is going to be slightly less than the energy require in the absence of this gravitational field.

Now, instead of having a pre-existing massive object, let us consider forming two electron-positron pairs simultaneously. The energy required for this is going to be (slightly) less the closer the two pairs are because of their gravitational interaction with each other.

Finally let us ask the question: how close must these pairs be for the energy requirement to be zero? An overly simplified equation might read something like: E=m*c2g*m2/(4*r) = 0; solve for r given a fixed m, or solve analytically for r as a function of m--I get r = m*g/(4*c2). If I take the mass of matter in the observable universe as 1053 kg, then r ≈ 2*1025 meters (2 billion light years), which is obviously wrong, but it shows that such a concept is, in principle, possible to consider, just with less simplistic models...
« Last Edit: 29/10/2014 17:43:46 by chiralSPO »
 

Offline jeffreyH

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 3913
  • Thanked: 53 times
  • The graviton sucks
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #26 on: 29/10/2014 20:05:41 »
My understanding of the "negative energy" phenomenon of gravity is something along these lines:

Imagine two photons of sufficiently high energy interact to produce an electron positron pair in some hypothetical otherwise empty universe. We can calculate the amount of energy the photons need to have for this to happen.

Now imagine the same reaction occurs very near to a massive object (in a large gravitational field). The energy required for this to happen is going to be slightly less than the energy require in the absence of this gravitational field.

Now, instead of having a pre-existing massive object, let us consider forming two electron-positron pairs simultaneously. The energy required for this is going to be (slightly) less the closer the two pairs are because of their gravitational interaction with each other.

Finally let us ask the question: how close must these pairs be for the energy requirement to be zero? An overly simplified equation might read something like: E=m*c2g*m2/(4*r) = 0; solve for r given a fixed m, or solve analytically for r as a function of m--I get r = m*g/(4*c2). If I take the mass of matter in the observable universe as 1053 kg, then r ≈ 2*1025 meters (2 billion light years), which is obviously wrong, but it shows that such a concept is, in principle, possible to consider, just with less simplistic models...

For a start you have no kinetic energy in your mass-energy term. You can't subtract from M*c^2 because then you are removing mass energy from the particle. Consider Ke to be the positive kinetic energy of the particle. Then -Ke is the gravitational energy (sorry John ). If -Ke falls off with the inverse square of the field the particle gradually loses all forward momentum away from the source. You then ultimately slow down the mass by more than 100% of its original velocity. This is not only the subtraction of forward momentum but also of internal kinetic energy. It can always be considered a process of slowing of momentum even when it causes an acceleration. However the acceleration is then a positive momentum in the negative direction. This does NOT mean that gravitation has negative energy. That one stumped Maxwell and others. We just don't know the mechanism of this action yet.
 

Offline acsinuk

  • Sr. Member
  • ****
  • Posts: 235
  • Thanked: 1 times
    • View Profile
    • electricmagnofluxuniverse.blogspot.com
Re: Is the total energy in the Universe conserved?
« Reply #27 on: 30/10/2014 09:17:35 »
But surely gravitational force is insignificant compared to the even the weak electric force like 10^25 so why try and balance the vacuum of space with gravity. Look to the electric force or EMF differences between solar objects.  It can't be measured directly but surely you do not think the surface potential of Mars much less the sun is the same as ours on earth?
 

Offline JohnDuffield

  • Sr. Member
  • ****
  • Posts: 488
  • Thanked: 1 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #28 on: 30/10/2014 13:01:09 »
Imagine two photons of sufficiently high energy interact to produce an electron positron pair in some hypothetical otherwise empty universe. We can calculate the amount of energy the photons need to have for this to happen. Now imagine the same reaction occurs very near to a massive object (in a large gravitational field). The energy required for this to happen is going to be slightly less than the energy require in the absence of this gravitational field.
This is all fair enough. But note that it still takes positive energy to make the pair. Yes it's less positive energy, but it's still positive. There's no actual negative energy anywhere.

Now instead of having a pre-existing massive object, let us consider forming two electron-positron pairs simultaneously. The energy required for this is going to be (slightly) less the closer the two pairs are because of their gravitational interaction with each other.
But not so much as to be measurable. You need a whole planet's worth of matter for that.

Finally let us ask the question: how close must these pairs be for the energy requirement to be zero?
There is no point at which you can make electron-positron pairs out of no energy.
 

Offline JohnDuffield

  • Sr. Member
  • ****
  • Posts: 488
  • Thanked: 1 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #29 on: 30/10/2014 13:09:27 »
Consider Ke to be the positive kinetic energy of the particle. Then -Ke is the gravitational energy (sorry John )
The kinetic energy is positive. So if the energy you added to the brick when you lifted it. When you dropped it, some of the mass-energy of the brick, the internal kinetic energy, is converted into external kinetic energy. Again there's no actual negative energy anywhere.

If -Ke falls off with the inverse square of the field the particle gradually loses all forward momentum away from the source.
When you throw the brick up, external kinetic energy is converted into internal kinetic energy. Conservation of energy applies.

You then ultimately slow down the mass by more than 100% of its original velocity. This is not only the subtraction of forward momentum but also of internal kinetic energy. It can always be considered a process of slowing of momentum even when it causes an acceleration. However the acceleration is then a positive momentum in the negative direction. This does NOT mean that gravitation has negative energy. That one stumped Maxwell and others.
This isn't clear.

We just don't know the mechanism of this action yet.
I think we do actually. It's down to the way light bends, and the wave nature of matter. See post number 2 on this thread for my stab at explaining it.
 

Offline jeffreyH

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 3913
  • Thanked: 53 times
  • The graviton sucks
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #30 on: 30/10/2014 21:52:53 »
Consider Ke to be the positive kinetic energy of the particle. Then -Ke is the gravitational energy (sorry John )
The kinetic energy is positive. So if the energy you added to the brick when you lifted it. When you dropped it, some of the mass-energy of the brick, the internal kinetic energy, is converted into external kinetic energy. Again there's no actual negative energy anywhere.

None of the mass energy of the brick is lost at all. Its momentum changes and the rate of energy flux changes, that's all.

If -Ke falls off with the inverse square of the field the particle gradually loses all forward momentum away from the source.
When you throw the brick up, external kinetic energy is converted into internal kinetic energy. Conservation of energy applies.

What on earth is external kinetic energy? It has to have a source.

You then ultimately slow down the mass by more than 100% of its original velocity. This is not only the subtraction of forward momentum but also of internal kinetic energy. It can always be considered a process of slowing of momentum even when it causes an acceleration. However the acceleration is then a positive momentum in the negative direction. This does NOT mean that gravitation has negative energy. That one stumped Maxwell and others.
This isn't clear.

Mathematically it's very clear.

We just don't know the mechanism of this action yet.
I think we do actually. It's down to the way light bends, and the wave nature of matter. See post number 2 on this thread for my stab at explaining it.

How does gravity affect a wave in such a way that it reverses momentum. If you can demonstrate a proof of that then you've cracked it.
 

Offline JohnDuffield

  • Sr. Member
  • ****
  • Posts: 488
  • Thanked: 1 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #31 on: 31/10/2014 10:35:24 »
None of the mass energy of the brick is lost at all. Its momentum changes and the rate of energy flux changes, that's all.
Check out the mass deficit. The kinetic energy of the falling brick doesn't come from nowhere.

What on earth is external kinetic energy? It has to have a source.
Drop a brick on your toe to really appreciate what it is. And it does have a source. The brick. When you lifted that brick you did work on the brick. You added energy to the brick.   

How does gravity affect a wave in such a way that it reverses momentum. If you can demonstrate a proof of that then you've cracked it.
It just bends it. There's proof of light being bent by the Sun, and proof of the wave nature of matter, but there's no proof that I know about of gravity bending the electron wave like my depiction. That's an inference. An obvious one IMHO, but I can't explain why it hasn't been common knowledge for decades.

« Last Edit: 31/10/2014 10:37:42 by JohnDuffield »
 

Online yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11979
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #32 on: 31/10/2014 19:06:39 »
John, been to the pub, so you better take this with a pinch of salt :)

though, I think you're missing something citing this. Stephen Hawking defined it this way. "Two pieces of matter that are close to each other have less [positive] energy than the same two pieces a long way apart, because you have to expend energy to separate them against the gravitational force that is pulling them together"

If you take it as stated there is nothing wrong with his reasoning. As a 'system' in where you have to expend energy to move pieces from each other. Potential energy is not as I think of it 'locally defined', so experimentally existing, unless one first define a 'container' of some sort, and conservation laws, that need this bookkeeping to present our equilibrium.

where I differ it is avoiding the 'container' but wanting to keep the conservation laws. To do that I presume that it is possible to build dimensions and a universe from locality, which it is, locally and experimentally.
==

To me, if I now was unclear before (quite often I'm afraid) 'negative energy' is similar to that hole that needs to be filled in charge. There's something missing to get back to a balance, and the universe abhors imbalance.
« Last Edit: 31/10/2014 19:25:35 by yor_on »
 

Online yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11979
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #33 on: 31/10/2014 19:18:02 »
The difference between Hawking's example and 'potential energy' is that there is nothing 'potential' with the energy you have to expend to move those pieces, locally defined. potential energy is ideally a 'virtual' bookkeeping, defining our universe, and as I think at the moment, a result of conservation laws existing.
 

Offline jeffreyH

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 3913
  • Thanked: 53 times
  • The graviton sucks
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #34 on: 31/10/2014 20:20:33 »
On all the bending nonsense I will say this. You do not have to have a physical curvature of trajectory for gravity to operate. If an object is propelled exactly perpendicular to the surface generating the gravitational field it will go straight up, stop, and come straight back down. While over time it will describe a parabola in space it won't. Curvature is in the gradient of change and not merely a physical curvature of trajectory.
 

Offline jeffreyH

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 3913
  • Thanked: 53 times
  • The graviton sucks
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #35 on: 31/10/2014 23:21:43 »
But surely gravitational force is insignificant compared to the even the weak electric force like 10^25 so why try and balance the vacuum of space with gravity. Look to the electric force or EMF differences between solar objects.  It can't be measured directly but surely you do not think the surface potential of Mars much less the sun is the same as ours on earth?

I have considered the em field in various ways but here it is energy conservation. Since gravity reduces kinetic energy and angular momentum it deserves equal if not more attention than the em field.
 

Offline JohnDuffield

  • Sr. Member
  • ****
  • Posts: 488
  • Thanked: 1 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #36 on: 01/11/2014 19:03:01 »
though, I think you're missing something citing this. Stephen Hawking defined it this way. "Two pieces of matter that are close to each other have less [positive] energy than the same two pieces a long way apart, because you have to expend energy to separate them against the gravitational force that is pulling them together"
Nothing wrong with that.

If you take it as stated there is nothing wrong with his reasoning. As a 'system' in where you have to expend energy to move pieces from each other. Potential energy is not as I think of it 'locally defined', so experimentally existing, unless one first define a 'container' of some sort, and conservation laws, that need this bookkeeping to present our equilibrium.
It is. If you throw a brick upwards, you give the brick kinetic energy. The brick slows down and this kinetic energy is converted into potential energy. But if you threw it upwards at 11km/s it's got escape velocity, and it escapes the system, taking all that kinetic/potential energy with it.   

where I differ it is avoiding the 'container' but wanting to keep the conservation laws. To do that I presume that it is possible to build dimensions and a universe from locality, which it is, locally and experimentally.
Sorry yor_on, I don't know what you mean by that.

To me, if I now was unclear before (quite often I'm afraid) 'negative energy' is similar to that hole that needs to be filled in charge. There's something missing to get back to a balance, and the universe abhors imbalance.
There just isn't any negative energy. Everything that exists is made of positive energy. There's just nothing out there that you can combine with something else to be left with nothing.
 

Online syhprum

  • Neilep Level Member
  • ******
  • Posts: 3813
  • Thanked: 19 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #37 on: 01/11/2014 21:45:59 »
When you say that the gravitational field can not be shielded you must be implying that the graviton has zero mass as even the very low mass Neutrino can be shielded against in theory.
 

Offline jeffreyH

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 3913
  • Thanked: 53 times
  • The graviton sucks
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #38 on: 01/11/2014 22:47:39 »
When you say that the gravitational field can not be shielded you must be implying that the graviton has zero mass as even the very low mass Neutrino can be shielded against in theory.

Any theory of gravity shielding has to overcome time dilation. So in one discrete region time has to move differently from the immediate surroundings. Even correcting for nanoseconds is some feat.
 

Online yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11979
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #39 on: 04/11/2014 21:19:02 »
Yeah John.

"    where I differ it is avoiding the 'container' but wanting to keep the conservation laws. To do that I presume that it is possible to build dimensions and a universe from locality, which it is, locally and experimentally. "

Sorry yor_on, I don't know what you mean by that. " "

you're correct, I don't know either what I mean, I have a feeling for what I want to get to, and it has taken me years to recognize the importance of it. I started with wondering what 'frames of reference'  meant, and I'm still stuck on this one. But I have a hope that you guys will help me there, if you start to wonder about it.
=
Spelling sux. the worst of it is that writing too much English, I've found myself just as bad in Swedish :)
Divine justice I guess?
« Last Edit: 04/11/2014 21:40:27 by yor_on »
 

Online yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11979
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #40 on: 04/11/2014 21:22:28 »
Although, your universe is what you see, do you see what I say John?
 

Offline acsinuk

  • Sr. Member
  • ****
  • Posts: 235
  • Thanked: 1 times
    • View Profile
    • electricmagnofluxuniverse.blogspot.com
Re: Is the total energy in the Universe conserved?
« Reply #41 on: 05/11/2014 09:53:02 »
The existing time/space frames of reference in my view are secondary and do not consider what the universe is made of?  We know that matter is made of molecules of atoms and that inside the molecule is electromagnetic and electrostatic stuff.   Now that stuff is fundamental to the whole universe,   So the most important frame of reference is electromagnetic and we must at all times conserve the positive and negative charge balance inside a magnetic enclosure.   The MKS system needs expanding to include electrical units V*I*Cos$ which will define where the charges are electromagnetically as well as physically. CliveS
 

Offline JohnDuffield

  • Sr. Member
  • ****
  • Posts: 488
  • Thanked: 1 times
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #42 on: 05/11/2014 14:00:55 »
you're correct, I don't know either what I mean, I have a feeling for what I want to get to, and it has taken me years to recognize the importance of it. I started with wondering what 'frames of reference'  meant, and I'm still stuck on this one. But I have a hope that you guys will help me there, if you start to wonder about it.
When it comes to special relativity, a frame of reference is little more than a state of motion. When you add general relativity into the mix, it's also a depth of potential thing. IMHO the important thing to appreciate is that it's an abstract thing. You cannot point up to the clear night sky and say "hey look, there's a reference frame".   

Although, your universe is what you see, do you see what I say John?
Yes. But when you see something different to me, we're smart enough to get our heads together and compare notes, then work out that universe is really like.

Spelling sux. the worst of it is that writing too much English, I've found myself just as bad in Swedish
Hurdy gurdy hurdy!
« Last Edit: 05/11/2014 14:04:30 by JohnDuffield »
 

Offline acsinuk

  • Sr. Member
  • ****
  • Posts: 235
  • Thanked: 1 times
    • View Profile
    • electricmagnofluxuniverse.blogspot.com
Re: Is the total energy in the Universe conserved?
« Reply #43 on: 06/11/2014 09:45:20 »
The reference frame at present is space/motion related and that is part of the problem. The centre of the system used to be earth, then the sun and now it is the black hole at the centre of our galaxy Sag A* which is the magnetic hub.
So we must measure everything using our dimension system from that hub including the electric and magnetic orientation.
MKS + V*flux.   Where flux is area of I*Cos$
The x=0, y=0 and z=0 is okay [and our sun is x=27000 Ly ] but flux at galactic hub is induced -180deg as stars will then be 0deg orientation and all spin with north poles downwards thus repelling each other.       It complicates the physics I know but is necessary
 

Online yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11979
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: Is the total energy in the Universe conserved?
« Reply #44 on: 12/11/2014 21:26:16 »
That doesn't matter for defining a experiment John. It do matter for making them into a conceptual reality describing a 'common universe', but there is a difference between that universe and what you measure. one is a abstraction, the other is your reality.
 

The Naked Scientists Forum

Re: Is the total energy in the Universe conserved?
« Reply #44 on: 12/11/2014 21:26:16 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums