PrimalMinister

Could relativity be incorrect

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I know relativity has been 'proved' but how do you know its what is actually going on as opposed to something that works but is not true/real such as epicycles. How do we know this is not just a repeat of this, making theories that work but are not true/real. Relativity seems like this to me, it is obviously onto something but I don't think its the actual truth, i.e. I don't think space-time literally bends and warps, I think the equations work (in certain conditions) but are not describing actual reality.

Edited by PrimalMinister
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Epicycles work (it's Fourier components applied to a rotational system) but there is no underlying reason for things to work that way. No physical basis.

Relativity comes about because the speed of light is invariant.

Physics does not claim to describe reality. It describes how things behave. There's a significant amount of physics that quote blatantly admits that it is not real, and is only a conceptual calculational convenience for describing behavior.

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7 minutes ago, swansont said:

Physics does not claim to describe reality. It describes how things behave.

But its reality we are interested in right? I ask these questions because I am currently working on a paper suggesting the universe is a kind of cellular automata but its not going to be finished for a few months. If it turns out I am correct then it would be a paradigm shift (as it suggests the universe is infinite, eternal, immortal) and a theory of everything because it gets to the root of the universe (its the science underlying mathematics) and discovers the final truth about reality (that the universe is an infinite, eternal, immortal cellular automata). It answers questions like 'why is the universe mathematical' and 'why do we have the laws we do' but its incommensurable with some of modern physics although its complementary to most of it. This is why I asked this question, as a sanity check. And because I am fascinated by the universe and science. And its enjoyable to discuss it.

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7 minutes ago, PrimalMinister said:

But its reality we are interested in right? I ask these questions because I am currently working on a paper suggesting the universe is a kind of cellular automata but its not going to be finished for a few months. If it turns out I am correct then it would be a paradigm shift (as it suggests the universe is infinite, eternal, immortal) and a theory of everything because it gets to the root of the universe (its the science underlying mathematics) and discovers the final truth about reality (that the universe is an infinite, eternal, immortal cellular automata). It answers questions like 'why is the universe mathematical' and 'why do we have the laws we do' but its incommensurable with some of modern physics although its complementary to most of it. This is why I asked this question, as a sanity check. And because I am fascinated by the universe and science. And its enjoyable to discuss it.

Sounds like you are working on a philosophy paper — metaphysics. While some physicists might care (mostly theoreticians working on foundational issues) and see an impact on their work, I suspect most will not care all that much.

At the end of it all, theory has to be consistent with experiment. If it disagrees, the theory is wrong. So too for any philosophy that's behind the theory.

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Of course you are immersed in the old paradigm while a shift is occurring. Take quantum mechanics, if you want it to be deterministic instead of probabilistic you just plug in the orientation to the cellular automata, that's where the randomness is coming from. It's consistent with experiment (complimentary) and day to day life. What about the big bang, that has had to be patched every time the data has proved it wrong, the only reason its being held onto is because there is not a better explanation.

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48 minutes ago, PrimalMinister said:

Of course you are immersed in the old paradigm while a shift is occurring. Take quantum mechanics, if you want it to be deterministic instead of probabilistic you just plug in the orientation to the cellular automata, that's where the randomness is coming from. It's consistent with experiment (complimentary) and day to day life. What about the big bang, that has had to be patched every time the data has proved it wrong, the only reason its being held onto is because there is not a better explanation.

Right. 99+ % of the time the old paradigm is more correct than what may or may not emerge to replace it.

So it's like "don't quit your day job" while you invest in something new, you try to keep an open mind but stay with what has proven to work in the interim. You build on the past.

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6 hours ago, PrimalMinister said:

But its reality we are interested in right? I ask these questions because I am currently working on a paper suggesting the universe is a kind of cellular automata but its not going to be finished for a few months. If it turns out I am correct then it would be a paradigm shift (as it suggests the universe is infinite, eternal, immortal) and a theory of everything because it gets to the root of the universe (its the science underlying mathematics) and discovers the final truth about reality (that the universe is an infinite, eternal, immortal cellular automata). It answers questions like 'why is the universe mathematical' and 'why do we have the laws we do' but its incommensurable with some of modern physics although its complementary to most of it. This is why I asked this question, as a sanity check. And because I am fascinated by the universe and science. And its enjoyable to discuss it.

The reality that scientists know is expressed in the models. Veni, vidi, ad exemplum illud  (I came, I saw, I modelled it) :).

Edited by StringJunky

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8 hours ago, PrimalMinister said:

 What about the big bang, that has had to be patched every time the data has proved it wrong, the only reason its being held onto is because there is not a better explanation.

Firstly, the BB has never been shown to be wrong, rather some modifications at times has been needed: That's why a scientific theory always remains a scientific theory and the best explanation for what we observe.

Edited by beecee

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10 hours ago, PrimalMinister said:

I know relativity has been 'proved' but how do you know its what is actually going on as opposed to something that works but is not true/real such as epicycles. How do we know this is not just a repeat of this, making theories that work but are not true/real. Relativity seems like this to me, it is obviously onto something but I don't think its the actual truth, i.e. I don't think space-time literally bends and warps, I think the equations work (in certain conditions) but are not describing actual reality.

Nothing is really proven with scientific theories, but they do grow in certainty over time. Such theories as the BB, SR, GR, have so far stood the test of time and have been shown to be correct each within their zones of applicability. The BB and GR are totally complimentary of each other, although it is worth noting that each is only valid from t+10-43 seconds up to what we see today. Scientists/Physicists are attempting at this time to formulate a observable quantum gravity theory that covers that first 10-43 seconds. Such a theory would not  confine GR to the dustbin nor invlidate it, rather extend the zone of applicability outside of which GR operates. Newton's theory of gravity remains "correct" within its zone of applicability, [it is still exclusively used on most Earth based calculations and also sufficiently accurate for most space endeavours. We could in effect use GR and obtain the same answers with far greater accuracy and precision, but that precision is not needed in the main, and the simplicity of Newtons mathematics compared to the mathematics of GR, makes Newton the obvious choice.

Spacetime warpage and curvature in the presence of matter/energy is validated by the maths of GR. The latest illustration and discovered prediction of spacetime warpage/curvature is of course gravitational waves from colliding/merging BH binaries by aLIGO and its sister observatory.

http://www.hawking.org.uk/space-and-time-warps.html


https://www.quora.com/Why-do-objects-with-mass-warp-space-time                                         

Quote

 

  Why do objects with mass warp space-time? 

The question is posed as a "why" question, so strictly speaking it has no definitive answer. The concept of mass causing space-time to warp is a postulate on which Einstein's GR is built. And as of today, GR is known to be consistent with observation at all length-scales bigger than the Planck scale, which is why we (well, most of us) believe it must be right. But in principle there can be other theories, built on some different concepts.

Restricting ourselves to the realm of Einstein's GR, a more appropriate question would be "how do objects with mass warp space-time". And the answer to that lies in Einstein's field equations:

Gμν=8πTμνGμν=8πTμν
(A cosmological constant term may be added.)

This is a tensorial equation with 10 independent components. The tensor on the left encodes the curvature of space time in a not-so-straightforward way, whereas the tensor on the right is the stress-energy tensor (it's not just mass that causes the warping).

 

Let me now give you this excellent summary on the question of why which I have mentioned and shown before on other threads...a short 7 minute video by one of the greats of the 20th century.

https://www.youtube.com/watch?v=MO0r930Sn_8

 

Edited by beecee

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In the case of atomic clocks, one travelling round in a satellite and one on earth, how do we know the clock in the satellite is travelling into the future instead of just ticking faster?

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18 minutes ago, PrimalMinister said:

In the case of atomic clocks, one travelling round in a satellite and one on earth, how do we know the clock in the satellite is travelling into the future instead of just ticking faster?

What to you mean by "traveling into the future"?

Whether or not an orbiting clock runs faster or slower than one on the surface of the Earth depends on its orbital altitude. Below a certain height it will tick slower and above it it will tick faster.

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24 minutes ago, PrimalMinister said:

In the case of atomic clocks, one travelling round in a satellite and one on earth, how do we know the clock in the satellite is travelling into the future instead of just ticking faster?

Not sure that your question isn't a false dichotomy. 

Firstly we like relativity as an explanation as the calculation of the expected time dilation via the schwarztchild metric was predicted and then found to be accurate; it is always better when it is this way around. 

Secondly, your wording is dubious - time is dilated, clocks which are running normally in their own frame, can tick slower or faster when viewed from a different frame which is in relative motion, at a different gravitational potential, or both in the case of an orbitting satellite.  You need to be very careful when using terms like travelling into the future - it is the marrying up of linguistic terms like that and the mathematical formalism of the physical theory which causes many of the problems of understanding.   Clocks at a higher gravitational potential tick faster when viewed from the persepective of a local frame at lower gravitational potential and vice versa.  Clocks in relative motion tick slower when viewed from the local frame which the observer deems to be at rest.  "Travelling into the future" does that mean the same?

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I was told that if an astronaut travelled away from the planet near the speed of light and then came back a year later everyone on earth has aged 20 years. What is happening here? He has travelled into the future (despite never leaving the present).

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18 minutes ago, PrimalMinister said:

I was told that if an astronaut travelled away from the planet near the speed of light and then came back a year later everyone on earth has aged 20 years. What is happening here? He has travelled into the future (despite never leaving the present).

"Traveling into the future" is an ill-defined concept. In physics we compare clock readings, which is something that can be quantified.

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22 minutes ago, PrimalMinister said:

I was told that if an astronaut travelled away from the planet near the speed of light and then came back a year later everyone on earth has aged 20 years. What is happening here? He has travelled into the future (despite never leaving the present).

Which is exactly why we use less poetic, or preferably mathematical descriptions.  Time has been dilated - each tick of his clock has, from an earthbound perspective, taken longer.  If he had kept a (impossibly good) telescope trained on the earth he would not have seen any discontinuities or jumps into the future - just a (quite complicated and let's not go there quite now) change in the way time passes.  If the earth-bound scientists had kept a telescope trained on him again they would has seen him do everything he did with no jumps or gaps. 

 

Edited by imatfaal
cross-posted again - must type/think faster

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2 hours ago, PrimalMinister said:

I was told that if an astronaut travelled away from the planet near the speed of light and then came back a year later everyone on earth has aged 20 years. What is happening here? He has travelled into the future (despite never leaving the present).

Essentially I would have said you are correct and agreed you have traveled into the future: But I also see how that could confuse with the expertise of the previous two answers.:) Let me put it this way, the astronaut and everyone left on Earth, both see their own time, in their own frame of reference, both mechanically and biologically passing at 1 second per second. Each in their own frame experiences normality. Although each [the astronaut and those back on Earth] when viewing the other frame, sees their time as dilated or going slower...on face value, a paradox, which is often labelled the twin paradox. Briefly the so called paradox is not really a paradox, as the traveling twin has invalidated his or her's state of inertia, as he needs to accelerate to near "ç" and decelerate to turn around to join his former twin back on Earth.

So then in effect, when the traveler has returned to Earth, he will be returning where the effect of time dilation means that 20 years has passed on the Earth he left behind, while he has only aged 1 year. 

A fuller explanation can be found at.....http://www.einstein-online.info/spotlights/Twins

Edited by beecee

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it would seem that in order to advance a particular "most correct" theory of everything, one would have to have an understanding of the particular steps that led to the BB, should that ever happen....

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9 hours ago, hoola said:

it would seem that in order to advance a particular "most correct" theory of everything, one would have to have an understanding of the particular steps that led to the BB, should that ever happen....

No, the most correct theory is the one that best matches the evidence and is consistent with other science (i.e. based on well-established science). But that's a topic for another thread.

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14 hours ago, hoola said:

it would seem that in order to advance a particular "most correct" theory of everything, one would have to have an understanding of the particular steps that led to the BB, should that ever happen....

!

Moderator Note

Stop! Don't hijack someone else's thread, open one of your own if you wish to pursue this concept!

 

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On 02/08/2017 at 1:12 PM, PrimalMinister said:

I know relativity has been 'proved' but how do you know its what is actually going on as opposed to something that works but is not true/real such as epicycles. How do we know this is not just a repeat of this, making theories that work but are not true/real. Relativity seems like this to me, it is obviously onto something but I don't think its the actual truth, i.e. I don't think space-time literally bends and warps, I think the equations work (in certain conditions) but are not describing actual reality.

"Bending and  warping space-time" is in fact a geometrical description of the mathematics. You definitely don't have to that literal, as a description of "hidden reality".
Here, just do a word search in one of the most famous papers, and see if you can find "bending and warping space-time", or something equivalent :

http://fourmilab.ch/etexts/einstein/specrel/www/

Special and General relativity are in fact mathematical models that make, for the time being, rather satisfying predictions about natural phenomena; they do not pretend to tell us "what really happens". However they do  strongly limit the options of what may be "really going on", or "under the hood" so to say. I have no idea if your "cellular automata" are compatible. But that brings us out of the realm of physics in the narrow sense of the word. Happily we have an appropriate sub forum for that. For a discussion of two historical interpretations that work, see http://www.scienceforums.net/topic/98845-models-for-making-sense-of-relativity-physical-space-vs-physical-spacetime/

 

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My limited understanding of general relativity is that it describes very accurately the way things move under gravity.  

With no gravitational effect, things move in straight lines, and it takes a force to accelerate them in any direction. Under GR, gravity isn't a force, but a curvature of space time. Seeing as there is no detectable force carrier, that's a good model to use. But if a force carrier is found, like the graviton, will GR then become like Newton's laws, an excellent working model, but not the definitive answer?

What bothers me about GR is that the force I feel pulling me to Earth is supposed to be indistinguishable from acceleration. But the big difference that find is that, if I am feeling acceleration at 9.81 metres per sec², I should have passed the speed of light years ago. 

So with gravity, it seems to flip. In remote space, you need force to go faster. In a gravitational field, you need a force to stay still.  

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33 minutes ago, mistermack said:

 What bothers me about GR is that the force I feel pulling me to Earth is supposed to be indistinguishable from acceleration. But the big difference that find is that, if I am feeling acceleration at 9.81 metres per sec², I should have passed the speed of light years ago. 

What you feel is the earth pushing up on you. You'd feel the same thing if you were standing in an elevator in deep space, and the elevator was accelerating at 1g.

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44 minutes ago, swansont said:

What you feel is the earth pushing up on you. You'd feel the same thing if you were standing in an elevator in deep space, and the elevator was accelerating at 1g.

Yes, I get that. 

But the difference is, in space you would be going faster and faster as a result of the force. Here on Earth, the same force keeps you stationary. 

Obviously, I'm not following the natural curvature of space time by remaining at the surface of the Earth, so I accept that that's what's happening in GR. But in the space elevator, I'm gaining kinetic energy. Here on Earth I'm not. Which makes me think it's not an exact match for acceleration.

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18 minutes ago, mistermack said:

Yes, I get that. 

But the difference is, in space you would be going faster and faster as a result of the force. Here on Earth, the same force keeps you stationary. 

Obviously, I'm not following the natural curvature of space time by remaining at the surface of the Earth, so I accept that that's what's happening in GR. But in the space elevator, I'm gaining kinetic energy. Here on Earth I'm not. Which makes me think it's not an exact match for acceleration.

How could you tell the difference?

 

Here on earth there are two effects: gravity and normal force.

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1 hour ago, mistermack said:

My limited understanding of general relativity is that it describes very accurately the way things move under gravity.  

With no gravitational effect, things move in straight lines, and it takes a force to accelerate them in any direction. Under GR, gravity isn't a force, but a curvature of space time. Seeing as there is no detectable force carrier, that's a good model to use. But if a force carrier is found, like the graviton, will GR then become like Newton's laws, an excellent working model, but not the definitive answer?

What bothers me about GR is that the force I feel pulling me to Earth is supposed to be indistinguishable from acceleration. But the big difference that find is that, if I am feeling acceleration at 9.81 metres per sec², I should have passed the speed of light years ago. 

So with gravity, it seems to flip. In remote space, you need force to go faster. In a gravitational field, you need a force to stay still.  

I am going to say +1 for encouragement about the emboldened and underlined bit.

You show definite improvement.

:)

 

The rest is, I'm afraid, a cheeky bit of misunderstanding.

Yes a good question "If I'm subject to constant acceleration why am I not moving at some colossal velocity?"

Standing on the surface of the Earth, the only acceleration you are subject to is the acceleration due to the Earth's (and your)rotation which is constantly changing your direction of motion.

You are not accelerating along the line from you to the centre of the Earth because you are subject to the balance of two forces, whose net sum is zero.
The resulting acceleration due to a zero (sum) is, of course, zero.
The two forces are the body force due to gravity downwards and the reaction between you and the surface upwards.

Meanwhile I see swans has replied, perhaps he can type more quickly than I can.

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