Gravity waves and the aether

[Mike Smith Cosmos]

You have the markers at the end points. There is no need to anything in between.

 

Yes what are the end points ' in ' , they just can not be coordinates written on some piece of paper . The coordinates if they are two distinct points within space time , cannot just be coordinates they must ' be in something , somewhere. what is the something .

 

I can describe a coordinate 2 meters out side my bedroom window 20 feet up. But there is nothing there . Except a bit of air and a long drop . You surely must have something there to act as your start point , similarly to act as the end point . I am asking what ' stuff ' are these two points in ? They cannon just be coordinates ? Surely ?

 

Mike

Edited July 8, 2016 by Mike Smith Cosmos

[disarray]

Ajb: Thanks for the comment about the present lack of deeper explanations for the attraction between, say, the sun and the earth. Science sometimes seems to be a mixture of descriptions and explanations. Scientists seem to be more easily satisfied with just the former (as long as it works and as long as the model fits the measurements) than those with more philosophical inclinations. But again, I have read in a few places that scientists don't particularly understand why bodies with (esp. greater) mass attract.

 

Could you elaborate on this relevant and very recent statement of yours though:

 

"Massless particle still carry energy-momentum and so can act as a source of gravity."

 

This statement seems to hint at a 'genuine' explanation as to the connection between mass and gravity (and even, as you state, massless particles).

Edited July 8, 2016 by disarray

[ajb]

But again, I have read in a few places that scientists don't particularly understand why masses attract.

Why is not really a science question. The best we can do is build models and make calculations therein. The closest to 'why' has to be in the mathematics.

 

 

"Massless particle still carry energy-momentum and so can act as a source of gravity."

 

This statement seems to hint at an explanation as to the connection between mass and gravity.

The Einstein field equations say 'geometry/gravity = matter/stuff'. The 'stuff' is mathematically including in the equations as the energy-momentum tensor associated with the 'stuff' - loosley it is the fact that 'stuff' has energy and momentum that connects mass and gravity/ '

[disarray]

Ajb: You state that "The Einstein field equations say 'geometry/gravity = matter/stuff'. The 'stuff' is mathematically including in the equations as the energy-momentum tensor associated with the 'stuff' - loosely it is the fact that 'stuff' has energy and momentum that connects mass and gravity/ '

 

Ah, so if scientists don't understand just why it is that the energy and momentum of matter/stuff is connected with gravity, then there is no benefit at this point to ferret through textbooks trying to find an explanation that is not (yet) there. And again, is there any possibility that the expansion of the universe has anything to do with such energy/momentum.

 

As an aside, is it a fair statement to say that the most significant advancement that Einstein made over Newton, when it comes to gravity, is the equivalence principle?

Edited July 8, 2016 by disarray

[Strange]

Yes what are the end points ' in ' , they just can not be coordinates written on some piece of paper .

 

Whatever. You said pegs in the ground. Great: stick with those. Those are you end points.

 

Now, when you measure the distance between them, you don't need there to be any "stuff" there to define the distance.

 

We were told, when we were at school, that the shortest distance between two points is a straight line. So we assume that when we measure the distance between those pegs that we are measuring a straight line.

 

Well, it turns out that they lied to us (and our intuitive view of the world is wrong). The shortest distance between two points is not necessarily a straight line. So when you measure the distance between those pegs, the distance you measure may follow a curve.

 

You keep insisting that the world matches your view of how it should be. Our intuitions about the world are often wrong. This is one example.

[ajb]

Ah, so if scientists don't understand why energy and momentum equals matter/stuff, then there is no benefit at this point to ferret through textbooks trying to find an explanation that is not (yet) there.

More than that, we don't really expect an answer to 'why'. The best we can do is hand you a model and we can discuss mechanism within that model. But really the question why is one for philosophy.

 

 

As an aside, is it a fair statement to say that the most significant advancement that Einstein made over Newton, when it comes to gravity, is the equivalence principle?

It depends what you mean by the equivalence principle. Newton thought - correctly it seems - that inertial mass and gravitational mass are the same. This is the weak equivalance principle. Another way of putting it is that gravity does not care about the material properties of bodies only their masses - in Newtonian gravity that is.

 

 

This form of the equivalence principle is clearly older than the one given by Einstein, which basically says that locally all non-gravitational physics reducues to that of special relativity.

Edited July 8, 2016 by ajb

[disarray]

Ajb: You state that "The best we can do is hand you a model and we can discuss mechanism within that model. But really the question why is one for philosophy."

 

I presume that science can often tell us the why of things better with some phenomena than with others, e.g., thunder, volcanic eruptions, rain, etc.

 

I agree that the question might be one for philosophy, if by that you mean the philosophy of science (e.g., the sort of lateral thinking involved in Hume and Einsteins efforts) as opposed to the sort of idle armchair (metaphysical) philosophizing that logical positivism tried to put an end to.

Edited July 8, 2016 by disarray

[swansont]

Yes what are the end points ' in ' , they just can not be coordinates written on some piece of paper . The coordinates if they are two distinct points within space time , cannot just be coordinates they must ' be in something , somewhere. what is the something .

 

 

You keep repeating this, but as Strange has said, you are insisting that nature conform to your world view. That's not how it works.

[ajb]

I presume that science can often tell us the why of things better with some phenomena than with others, e.g., thunder, volcanic eruptions, rain, etc.

We have an understanding of the mechanisms involved, that is true. But 'why' is still really a philosophical question - 'how' is a better question for science.

 

And as we get to more and more fundamental questions in science it gets even harder to explain things simply and without much mathematics.

[Strange]

I presume that science can often tell us the why of things better with some phenomena than with others, e.g., thunder, volcanic eruptions, rain, etc.

 

To some level, yes. So we can talk about thunder as a noise created by electrical discharge.

 

If we take the simplest bit of that (ignoring the complexity of why an electrical discharge should create noise): Why do we hear noise? Well, we can say that noise is a change in pressure in air. And that the pressure is caused by atoms bouncing off one another (crudely).

 

But why do atoms bounce off each other? Well, they have electrons which have a negative charges and, as we learnt school, like charges repel.

 

Why do like charges repel? Well, um, er, they, you know, ... fields and er ... quantum electrodynamics .. feynman diagrams, and you know, virtual photons and stuff....

 

At which point I would refer you to the video of Feynman being asked about magnetism and explaining why he can't answer the question.

 

At some point, "why" is always doomed to fail.

[geordief]

 

To some level, yes. So we can talk about thunder as a noise created by electrical discharge.

 

If we take the simplest bit of that (ignoring the complexity of why an electrical discharge should create noise): Why do we hear noise? Well, we can say that noise is a change in pressure in air. And that the pressure is caused by atoms bouncing off one another (crudely).

 

But why do atoms bounce off each other? Well, they have electrons which have a negative charges and, as we learnt school, like charges repel.

 

Why do like charges repel? Well, um, er, they, you know, ... fields and er ... quantum electrodynamics .. feynman diagrams, and you know, virtual photons and stuff....

 

At which point I would refer you to the video of Feynman being asked about magnetism and explaining why he can't answer the question.

 

At some point, "why" is always doomed to fail.

Does "why" ="how"^∞ ?

[StringJunky]

Does "why" ="how"^∞ ?

'Why' is about cause which is ultimately axiomatic i.e. it is based on a starting presumption. 'How' is about behaviour i.e. it is what is observed, which is what science deals with.

Edited July 8, 2016 by StringJunky

[geordief]

'Why' is about cause which is ultimately axiomatic i.e. it is based on a starting presumption. 'How' is about behaviour, which is what science deals with.

But does my "equation" show how people think they will get the "why" by following through (futilely) all the "hows" ?

 

I only meant it light heartedly.

[Strange]

Does "why" ="how"^∞ ?

 

If you have children, you would know that why = why² (defined recursively).

def why(x):
  a = answer(x)
  print(a)
  why(a)
  return

Edited July 8, 2016 by Strange

[swansont]

Ultimately the questions boil down to science being related to behavior we can observe. If we can't observe, we can't test the models. The model itself can't tell us why that model is the one that works; it's only comparison with experiment which can tell us that it does.

[geordief]

 

 

If you have children, you would know that why = why² (defined recursively).

def why(x):
  a = answer(x)
  print(a)
  why(a)
  return

No but I have seen the Midwich Cuckoos

[StringJunky]

 

 

If you have children, you would know that why = why² (defined recursively).

def why(x):
  a = answer(x)
  print(a)
  why(a)
  return

[Mike Smith Cosmos]

You keep repeating this, but as Strange has said, you are insisting that nature conform to your world view. That's not how it works.

I do not Know why , it's not meant as defiance, but on this matter of space -time , particularly space at the moment . I seem to to be on a ' different wavelength, somehow? ' I would like to peruse this either ( more than likely for my benefit ) unless somehow we are missing a trick ( then for others benefit.

 

Because there is a lot of blackness and lack of objects like planets, Suns etc it is very easy to think of space as nearly empty, nothing there , almost nothing at all . I think we all know that modern astronomy and space exploration and atomic science for that matter , has shown that there is in fact quite a lot out there ( even though we can't easily see it. Nonetheless , we have developed ideas , in our minds eye that SPACE is a very lonely empty space , there is no path or road to the moon , or anywhere else. It's space ships or nothing .

 

When we in history first became seafarers ( not sure could have been the Polynesian people ) no matter . Before that, the sea was a place to fear, drown or watch in awe and mystery . Now we surf it sail it , go in it on it , skim across two feet above it , in all manner of ways .

 

I am convinced we will look back at our space travel as 'pea nuts' . Currently we are still in fear and awe at its immensity and dangers. Maybe it's this total emptiness that " shivers our timbers " .

 

But maybe we will find that is far from empty . Even now today , there is talk of sub atomic particles we can't see , neutrinos going right through us in there millions, quantum particles ,atoms electrons , virtual particles, Higgs , charge , gravitons , bosons , leptons , gluons , photons , dark matter and dark energy . I am not sure there is even going to be any room left for us to get in there . If we then add in the established planets Suns stars , asteroids , comments.. ( oops ! Comets ) , molecular dust and gas .

 

Surely . With all this lot inhabiting space , how can we say there is nothing or a near vacuum in space . Surely this lot I have just listed make up some real ingredients. Thus for saying " there is something there , that we need to take account of , and ask is it making up a backdrop to gauge our distances, times and curvature in space against ?

 

If we were to call this backdrop a " name , say as example 'spacial backdrop' I " , not space, as this has this connotation of nothingness . And it could be quite fluid and moving much like the sea and atmosphere proved to be . Then maybe we could use this Spacial Backdrop as a reasonably consistent reference to make measurements , against . ,

 

Mike

Edited July 8, 2016 by Mike Smith Cosmos

[geordief]

But maybe we will find that is far from empty . Even now today , there is talk of sub atomic particles we can't see , neutrinos going right through us in there millions, quantum particles ,atoms electrons , virtual particles, Higgs , charge , gravitons , bosons , leptons , gluons , photons , dark matter and dark energy . I am not sure there is even going to be any room left for us to get in there . If we then add in the established planets Suns stars , asteroids , comments (?) , molecular dust and gas .

 

Surely . With all this lot inhabiting space , how can we say there is nothing or a near vacuum in space . Surely this lot I have just listed make up some real ingredients. Thus for saying " there is something there , that we need to take account of , and ask is it making up a backdrop to gauge our distances, times and curvature in space against ?

 

 

Personally I think of space as the gaps between all those ingredients you have listed(although I won't stand by that).

 

You seem to have populated interstellar space with "comments" . The internet and its various forums has a lot to answer for

Edited July 8, 2016 by geordief

[Strange]

 

Surely . With all this lot inhabiting space , how can we say there is nothing or a near vacuum in space .

 

It is not nothing, although it is a near vacuum. For example interstellar gas has about 1 atom per cubic centimetre. There are probably a lot more photons and (maybe) neutrinos per cubic cm.

 

Space may be full of "stuff" but that is not relevant to the question of how distances and time are affected by mass. (Apart from the fact that some that stuff has mass.)

[swansont]

I am convinced we will look back at our space travel as 'pea nuts' . Currently we are still in fear and awe at its immensity and dangers. Maybe it's this total emptiness that " shivers our timbers " .

 

I think that carries zero weight in the scientific investigation. "Here be dragons" might be a fear of someone venturing there, but it poses no danger to someone doing science from afar.

 

But maybe we will find that is far from empty . Even now today , there is talk of sub atomic particles we can't see , neutrinos going right through us in there millions, quantum particles ,atoms electrons , virtual particles, Higgs , charge , gravitons , bosons , leptons , gluons , photons , dark matter and dark energy .

Neutrinos, photons, and electrons, etc. and the classification of such particles: bosons, fermions (leptons and quarks), etc. all have experimental evidence to support them.

 

I am not sure there is even going to be any room left for us to get in there . If we then add in the established planets Suns stars , asteroids , comments.. ( oops ! Comets ) , molecular dust and gas .

 

Surely . With all this lot inhabiting space , how can we say there is nothing or a near vacuum in space . Surely this lot I have just listed make up some real ingredients. Thus for saying " there is something there , that we need to take account of , and ask is it making up a backdrop to gauge our distances, times and curvature in space against ?

If you paid attention, you would find quite a few people saying that "empty space" isn't empty. But that's not the same as saying that it is a medium.

 

If we were to call this backdrop a " name , say as example 'spacial backdrop' I " , not space, as this has this connotation of nothingness . And it could be quite fluid and moving much like the sea and atmosphere proved to be . Then maybe we could use this Spacial Backdrop as a reasonably consistent reference to make measurements , against . ,

The problem here is basically "been there and done that". Scientists tried this and it failed. And they tried it with a lot more rigor and experimentation than you have presented. So if you present it again, but without any rigor or experimentation, how do you think you will fare?

[MigL]

It is even more fundamental than that.

Relativity does NOT allow for a 'backdrop' or a 'stage' against which events unfold.

This would be a preferred frame which would render relativity useless.

 

So again I ask, would you do away with relativity ( an excellent model which agrees extremely well with observation ) and replace it with an aether model in which ...

 

a) the aether is composed of 'normal' stuff ( that you find acceptable ), and the model doesn't agree with observation.

 

or...

 

b) the aether has some fantastical properties that make it undetectable, and the model is indistinguishable from relativity.

 

( notice that option a makes the aether model unworkable while option b makes it unneeded )

[Strange]

So maybe this is the answer Mike is looking for:

 

Spacetime is made of "Magic FooFoo", which is a completely undetectable material about which we know nothing and, because it is undetectable, cannot know anything.

 

So, Mike there you go. Magic FooFoo is the answer. That is what curves when we talk about gravity. You are free to invent any properties you like for this material as long as they do not make it detectable.

 

So if you want it to be coloured, then it can be Invisible Magic Pink, Invisible Magic Blue or any other similar colour.

 

Its density can be whatever you like, as long as you can think of a reason why it is always measured to be zero.

 

Its velocity can be whatever you like, as long as you can think of a reason why it is always measured to be zero.

 

Are you happy now? You can have a bucket of Magic FooFoo (which is indistinguishable from any other empty bucket) and play with it to your hearts content.

[Mike Smith Cosmos]

.

" Methinks you are taking the Michael "

 

Here I am your genuine thinker . May have taken a bit too much of a sharp turn today and a bump on the head , and a restless night trying to get my head around , what is in space that I can , " come to grips with ? " Think it was the sudden breakout of Summer heat in the U.K

 

Mike

Edited July 8, 2016 by Mike Smith Cosmos

[Markus Hanke]

Relativity does NOT allow for a 'backdrop' or a 'stage' against which events unfold.

 

 

Indeed. And the problem reaches even further than initially meets the eye, because if you eliminate local Lorentz invariance, you inadvertently also eliminate the CPT invariance of quantum field theory. That means that, not only would you bring down relativity in the classical realm, but you would also bring down the entire Standard Model with it.