Robittybob's Law - orbital issue???

[J.C.MacSwell]

Yes.

Are you referring to the mass of the moon, or to the moon's contribution to the mass of the Earth/Moon System?

[Robittybob1]

Are you referring to the mass of the moon, or to the moon's contribution to the mass of the Earth/Moon System?

I'll let Swansont speak for himself but from an energy point of view the Moon gains orbital energy but a lot less energy than what is lost from the Earth (from friction from the tidal movements) and slowing of the rotation rate, so there is a net loss to the system from the process of tidal acceleration AFAIK.

(My opinion was based on the article in Wikipedia https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_momentum_and_energy

 

 

Effectively, energy and angular momentum are transferred from the rotation of Earth to the orbital motion of the Moon (however, most of the energy lost by Earth (-3.321 TW) is converted to heat by frictional losses in the oceans and their interaction with the solid Earth, and only about 1/30th (+0.121 TW) is transferred to the Moon). The Moon moves farther away from Earth (+38.247±0.004 mm/y), so its potential energy (in Earth's gravity well) increases.

Edited March 3, 2016 by Robittybob1

[swansont]

Are you referring to the mass of the moon, or to the moon's contribution to the mass of the Earth/Moon System?

 

 

The moon. The work done is internal to the system so that wouldn't change except for any energy that needs to be shed from it to make this work.

[J.C.MacSwell]

 

 

The moon. The work done is internal to the system so that wouldn't change except for any energy that needs to be shed from it to make this work.

So without the moon changing materially, or with regard to KE, it's mass increases due to it's change in position with respect to the Earth?

[swansont]

So without the moon changing materially, or with regard to KE, it's mass increases due to it's change in position with respect to the Earth?

 

 

Yes. You change the energy (other than KE), you change the mass. It'll be a tiny fractional amount, but it will be different.

[Robittybob1]

 

 

Yes. You change the energy (other than KE), you change the mass. It'll be a tiny fractional amount, but it will be different.

It seems that "the KE is reduced, the higher the orbit the slower the Moon needs to travel, so it appears the KE is converted to PE and that in turn increases its mass".

I've never seen it written like that before, but it seems possible. Any agreement or is this wrong?

[swansont]

It seems that "the KE is reduced, the higher the orbit the slower the Moon needs to travel, so it appears the KE is converted to PE and that in turn increases its mass".

I've never seen it written like that before, but it seems possible. Any agreement or is this wrong?

 

 

Unnecessary detail. The object has additional energy that isn't KE. That's all you need.

[Robittybob1]

 

 

Unnecessary detail. The object has additional energy that isn't KE. That's all you need.

It feels like new territory to me, I've never seen this sort of thing ever been discussed before. I really want the discussion to go away from a discussion of the Moon but what happens when energy is lost as per gravitational radiation (GE, Gravitational Energy). Is there a mass loss in this situation? For if there was there was no formula that accounted for this changing mass, but that might be what is required.

You say it is unnecessary detail but in the binary decaying orbit the KE is going up, so we will have to convert mass to KE and GE but the KE does not contribute to the mass any longer. Is that right? That is really interesting when you think about it.

[swansont]

It feels like new territory to me, I've never seen this sort of thing ever been discussed before. I really want the discussion to go away from a discussion of the Moon but what happens when energy is lost as per gravitational radiation (GE, Gravitational Energy). Is there a mass loss in this situation? For if there was there was no formula that accounted for this changing mass, but that might be what is required.

Have you been paying attention to the gravitational radiation discussion? ~3 solar masses worth of energy was converted to the radiation.

 

This is an issue if you look at individual particles. It depends on where you draw the boundaries in defining your system.

 

You say it is unnecessary detail but in the binary decaying orbit the KE is going up, so we will have to convert mass to KE and GE but the KE does not contribute to the mass any longer. Is that right? That is really interesting when you think about it.

The more detail you try and attach, the less general the concept is.

 

The KE never contributes to the mass, and in the situation described the KE goes down, not up, so for the moon there is no conversion of mass to KE. The additional energy in the moon receding comes from the earth.

 

This is all about bookkeeping — properly applying conservation of energy. In E² = p²c² + m²c⁴ there are two contributions: CoM motion (in the momentum term) which is the KE, and the mass. That's it. We find it convenient in many cases to talk about even more divisions of energy. One could even argue, I suppose, that since the moon's KE is rotational, that you roll that all up into the mass. Again, it depends on what you're looking at and how you define things.

[Robittybob1]

Have you been paying attention to the gravitational radiation discussion? ~3 solar masses worth of energy was converted to the radiation.

 

This is an issue if you look at individual particles. It depends on where you draw the boundaries in defining your system.

 

The more detail you try and attach, the less general the concept is.

 

The KE never contributes to the mass, and in the situation described the KE goes down, not up, so for the moon there is no conversion of mass to KE. The additional energy in the moon receding comes from the earth.

 

This is all about bookkeeping — properly applying conservation of energy. In E² = p²c² + m²c⁴ there are two contributions: CoM motion (in the momentum term) which is the KE, and the mass. That's it. We find it convenient in many cases to talk about even more divisions of energy. One could even argue, I suppose, that since the moon's KE is rotational, that you roll that all up into the mass. Again, it depends on what you're looking at and how you define things.

I have been following it intently especially if they were to mention how long the merging binary BHs had been orbiting each other, (it was said they had likely been orbiting for a billion years). Also the finding about the 3 solar masses of energy (but that amount was just in the last 0.3 seconds).

According to the GE equations throughout that billion year orbital decay they would have been radiating energy and falling in toward each other. OK the situation gets very serious in the final moments and that is why it was able to be detected over 1.3 billion light years away.

Now do you accept that the binary BHs were losing mass from the gravitational radiation (G-rad) from the moment they became a binary system orbiting each other? (That is a billion plus years ago)

 

All the time the BHs may have been accumulating mass as BHs do but that is a separate issue. I have bolded the question just so you all know the question I have been wanting answered. For if the answer is yes there doesn't seem to be allowance for this mass loss in the equations on G-rad. It would be rather a simple process to convert the energy loss into mass and continually subtract that amount of mass and use the reduced mass of each star/BH into the orbital period equations.

It isn't so easy to predict the BHs as their mass would be growing due to their nature of taking in mass but the binary stars aren't thought of accumulating mass like that.

Edited March 3, 2016 by Robittybob1

[swansont]

Any system radiating energy would be losing mass. Just a like an atom emitting a photon would be losing mass and one that has absorbed a photon has greater mass than before.

[Robittybob1]

Any system radiating energy would be losing mass. Just a like an atom emitting a photon would be losing mass and one that has absorbed a photon has greater mass than before.

Thanks, so I wonder what J.C.MacSwell is thinking.

[J.C.MacSwell]

Thanks, so I wonder what J.C.MacSwell is thinking.

Essentially same as Swansont except, as you can tell from my last few posts, I am not clear on how the GE is accounted for with regard to mass. If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass, 1 kg, (but say warmed up to a higher temperature, then over 1 kg, which I am sure is correct)

 

So I'm thinking I have to do some...thinking

[Robittybob1]

Essentially same as Swansont except, as you can tell from my last few posts, I am not clear on how the GE is accounted for with regard to mass. If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass, 1 kg, (but say warmed up to a higher temperature, then over 1 kg, which I am sure is correct)

 

So I'm thinking I have to do some...thinking

I am sure we are going down totally new territory here, something nevertheless has been a possibility for a long time.

As you say "If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass, 1 kg, (but say warmed up to a higher temperature, then over 1 kg, which I am sure is correct)" this is the usual way of thinking.

But how about "If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass plus some additional mass (???) (not more molecules but just more energy per molecule), 1 kg + ???, (but say warmed up to a higher temperature, then over 1 kg +???, could this be correct?)

I started a thread on conservation of energy in Relativity (http://www.scienceforums.net/topic/93590-conservation-of-energy-in-gr-split-from-universal-laws/ ) and found that ideas like this seemed to be what is lacking. That was why I did not post in that thread other than the OP in #4 (since the thread was split off another it technically wasn't myself who started it but it was from an idea in the first 3 posts.)

Swansont can direct us how we operate without having to go across two threads in an area of science which seems speculative.

We need some sort of immunity to discuss this step by step and openly.

 

Do you feel that there is a connection between what we are discussing here under RB law and conservation of energy in GR? I think that is where we are at.

Edited March 3, 2016 by Robittybob1

[swansont]

Essentially same as Swansont except, as you can tell from my last few posts, I am not clear on how the GE is accounted for with regard to mass. If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass, 1 kg, (but say warmed up to a higher temperature, then over 1 kg, which I am sure is correct)

 

So I'm thinking I have to do some...thinking

 

 

I had the good fortune a few years ago to spend a couple of hours talking physics with a Nobel prize winner, along with my colleagues (two of whom had been postdocs in his group). A similar subject came up, concerning incorporating GR with the rest of physics, if we could ever do measurements precise enough. I was able to understand enough of what was going on to comment that this meant we would have to worry about whether the value of the electron mass was defined at the bottom of the mountain or at the top, and he confirmed that this was the issue.

 

My colleagues were mildly impressed, because they hadn't been able to follow the discussion as well as I had. Truth is, it was because I was used to similar discussions here that the thought had occurred to me. If hadn't spent time deconstructing crackpot arguments or explaining what I knew of GR effects to interested amateurs, I probably would have been similarly lost.

I am sure we are going down totally new territory here, something nevertheless has been a possibility for a long time.

As you say "If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass, 1 kg, (but say warmed up to a higher temperature, then over 1 kg, which I am sure is correct)" this is the usual way of thinking.

But how about "If say, you took a kg of lead from Earth and dropped it off on the moon at the same temperature I would have assumed it was the same mass plus additional mass (not more molecules but just more energy per molecule), 1 kg + ???, (but say warmed up to a higher temperature, then over 1 kg +???, could this be correct?)

I started a thread on conservation of energy in Relativity (http://www.scienceforums.net/topic/93590-conservation-of-energy-in-gr-split-from-universal-laws/ ) and found that ideas like this seemed to be what is lacking.

Swansont can direct us how we operate without having to go across two threads in an area of science which seems speculative.

We need some sort of immunity to discuss this step by step and openly.

 

I don't think this has all that much to do with the details of GR issues with conservation of energy. I think you can deal with it purely from a SR point of view. For all I know, there may be things in how GR defines systems that throws a wrench into all of this if you do a full-blown GR analysis. As I said before, what you do depends on how you define your system

 

I was merely commenting that SR divides total energy into two categories: CoM motion (translational kinetic energy) and mass. That's it.

[Robittybob1]

 

 

I had the good fortune a few years ago to spend a couple of hours talking physics with a Nobel prize winner, along with my colleagues (two of whom had been postdocs in his group). A similar subject came up, concerning incorporating GR with the rest of physics, if we could ever do measurements precise enough. I was able to understand enough of what was going on to comment that this meant we would have to worry about whether the value of the electron mass was defined at the bottom of the mountain or at the top, and he confirmed that this was the issue.

 

My colleagues were mildly impressed, because they hadn't been able to follow the discussion as well as I had. Truth is, it was because I was used to similar discussions here that the thought had occurred to me. If hadn't spent time deconstructing crackpot arguments or explaining what I knew of GR effects to interested amateurs, I probably would have been similarly lost.

 

I don't think this has all that much to do with the details of GR issues with conservation of energy. I think you can deal with it purely from a SR point of view. For all I know, there may be things in how GR defines systems that throws a wrench into all of this if you do a full-blown GR analysis. As I said before, what you do depends on how you define your system

 

I was merely commenting that SR divides energy into two categories: CoM motion (translational kinetic energy) and mass. That's it.

That to me is amazing for Swansont did not read my post #89 first but we were both writing up on similar ideas. I did not know what Swanson was posting in #90 but we ended up talking about the same "new territory" topic.

Edited March 3, 2016 by Robittybob1

[J.C.MacSwell]

 

 

 

 

My colleagues were mildly impressed, because they hadn't been able to follow the discussion as well as I had. Truth is, it was because I was used to similar discussions here that the thought had occurred to me. If hadn't spent time deconstructing crackpot arguments or explaining what I knew of GR effects to interested amateurs, I probably would have been similarly lost.

Thanks. Nice to know my contributions have not gone unnoticed...(and here I always thought it was you helping me)

[Robittybob1]

Thanks. Nice to know my contributions have not gone unnoticed...(and here I always thought it was you helping me)

Well you (JC) have definitely helped me. Swansont still causes me to be fearful, but on this issue Swansont and I have been in line with each other even though we had stepped over the edge of classical physics. It has been a strange experience. Thanking all those who have contributed so far to a very personal thread.

 

 

....

I don't think this has all that much to do with the details of GR issues with conservation of energy. I think you can deal with it purely from a SR point of view. For all I know, there may be things in how GR defines systems that throws a wrench into all of this if you do a full-blown GR analysis. As I said before, what you do depends on how you define your system

 

I was merely commenting that SR divides total energy into two categories: CoM motion (translational kinetic energy) and mass. That's it.

OK but can we discuss all these topics together under the heading of RB law? I'm not strong in GR or SR but I'll have to get strong to continue the discussion. It is going to be difficult but that is my problem.

Next two steps:

1. How do I define my system?

2. Learn how SR divides total energy.

[Robittybob1]

The two postulates of Special Relativity. https://en.wikipedia.org/wiki/Postulates_of_special_relativity#Postulates_of_special_relativity

 

 

1. First postulate (principle of relativity)
The laws by which the states of physical systems undergo change are not affected, whether these changes of state be referred to the one or the other of two systems of coordinates in uniform translatory motion. OR: The laws of physics are the same in all inertial frames of reference.
2. Second postulate (invariance of c)
As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. OR: The speed of light in free space has the same value c in all inertial frames of reference.

Laws of physics same in all reference frames. This does not stop mass changing when moving from one inertial frame to the next, especially if there was a gravitational field being crossed in the process of taking the frame of Reference (FoR) from one site to another.

So if we take F= ma as the law in question the same amount of force will result in less acceleration if the mass has increased.

"If there was a gravitational field being crossed in the process of taking the frame of Reference (FoR) from one site to another."The words "gravitational field" could be replaced by a "magnetic field", or an "electrical field", a strong force or weak force.

I'm thinking wherever there is a force that has an absolute change. For instance the electron's trip to the top of the mountain does not have to be remembered if then later it is brought back to the bottom of the mountain.

 

 

.

 

As Einstein himself later acknowledged, the derivation of the Lorentz transformation tacitly makes use of some additional assumptions, including spatial homogeneity, isotropy, and memorylessness.

In the RB law SR cannot operate with the assumption of memorylessness. Intermediary steps result in memory e.g. "if there was a gravitational field being crossed in the process of taking the frame of Reference (FoR) from one site to another". You can't forget how you got there.

The electron in an inertial FoR (IFoR) at the bottom of the mountain does not have the same mass as in an IFoR at the top of the mountain. But the laws of physics will be the same in each IFoR.

Edited March 4, 2016 by Robittybob1

[swansont]

The two postulates of Special Relativity.

Laws of physics same in all reference frames. This does not stop mass changing when moving from one inertial frame to the next

especially if there was a gravitational field being crossed in the process of taking the frame of Reference (FoR) from one site to another.

So if we take F= ma as the law in question the same amount of force will result in less acceleration if the mass has increased.

 

 

If there's a gravitational field you are no longer in the realm of SR. In SR, the mass term is invariant; the total energy is not, because the energy from motion is relative.

[Robittybob1]

 

 

If there's a gravitational field you are no longer in the realm of SR. In SR, the mass term is invariant; the total energy is not, because the energy from motion is relative.

What I was trying to say was that the two sites have no gravitational field (GF) but in the process of taking the IFoR "physics laboratory" from one site to the other it passes through a GF. If that can't happen I can't look at the problem from a SR POV.

E.g. Can we do this "The lab is raised in the GF by 1 meter" or even more dramatic "the lab is transported from Earth to Mars".

If it never moved through a net changing force field the mass would be invariant.

Edited March 4, 2016 by Robittybob1

[swansont]

What I was trying to say was that the two sites have no gravitational field (GF) but in the process of taking the IFoR "physics laboratory" from one site to the other it passes through a GF. If that can't happen I can't look at the problem from a SR POV.

E.g. Can we do this "The lab is raised in the GF by 1 meter" or even more dramatic "the lab is transported from Earth to Mars".

If it never moved through a net changing force field the mass would be invariant.

 

 

 

If you only look at the initial and final conditions, what happens in the middle shouldn't matter (with a possible exception of cases where you must use GR rather than Newtonian gravity). Raising or lowering something could be addressed by looking at the equivalence principle — it should be no different than doing work, i.e. adding or subtracting energy.

[Robittybob1]

 

 

 

If you only look at the initial and final conditions, what happens in the middle shouldn't matter (with a possible exception of cases where you must use GR rather than Newtonian gravity). Raising or lowering something could be addressed by looking at the equivalence principle — it should be no different than doing work, i.e. adding or subtracting energy.

THe MM experiment was done on Earth in a GF and that was one of the proofs in a way of the statement light always travels at c.

So as long as the experiments to prove the laws of physics are done in the horizontal plane the GF has minimal effect. For where abouts in the Universe is this place of no GF that was used in Einstein's thought experiments? It is hard to imagine if you could access the same place or similar places in the Universe and have different rest masses at the end if you started off with identical masses to begin with (i.e. they were side by side at sometime in the past).

Einstein's thought experiments were not complicated by the thoughts of Dark Energy (DE) and Dark Matter (DM).

So in reality (for practical purposes) we are always going to be dealing with IFoR in different strength GFs and all we can do are experiments in the horizontal plane i.e. orthogonal to the GF.

Edited March 5, 2016 by Robittybob1

[Robittybob1]

Funny thing just about every site today has been saying KE is part of the mass, but not rest mass. I'll have to go through them again. What is the clue to understanding "KE never contributes to the mass...."?

 

what do you think of this exercise?

 

....

The KE never contributes to the mass, ....

This is all about bookkeeping — properly applying conservation of energy. In E² = p²c² + m²c⁴ there are two contributions: CoM motion (in the momentum term) which is the KE, and the mass. That's it. ......

Edited March 5, 2016 by Robittybob1

[Mordred]

KE doesnt contribute to rest mass as its a particle at rest. so momentum is zero. This is called nowadays the invariant mass. Inertial mass will increase with momentum via the formula Swansort provided. Here is the formulas

 

the kinetic energy of an object is the energy that it possesses due to its motion.

 

https://en.wikipedia.org/wiki/Mass_in_special_relativity

 

the formula Swansort provided is the total energy formula.

 

Don't confuse these equations with KE though the relativistic KE equation is

 

[latex]E_k=\sqrt{p^2m^2+m^2C^4}-mc^2[/latex]

 

notice the last formula subtracts the invariant (rest)mass from the total energy-momentum equation

 

invariant mass is given by

 

[latex]E=m_oc^2[/latex]

 

the total energy formula gives you the relativistic mass which most books and physicists no longer like using that term. As its often too subject to misunderstanding

 

"The concept of "relativistic mass" is subject to misunderstanding. That's why we don't use it. First, it applies the name mass - belonging to the magnitude of a 4-vector - to a very different concept, the time component of a 4-vector. Second, it makes increase of energy of an object with velocity or momentum appear to be connected with some change in internal structure of the object. In reality, the increase of energy with velocity originates not in the object but in the geometric properties of spacetime itself."

 

^{https://en.wikipedia.org/wiki/Relativistic_mass#Relativistic_mass}

Edited March 5, 2016 by Mordred