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Split from Lorentz-contraction


Charles 3781
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If the ship underwent contraction as it approached light-speed, wouldn't the hydrogen atoms inside the ship get so squeezed together, that they underwent nuclear fusion, and blew the ship apart in a gigantic nuclear explosion?

 

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20 minutes ago, Charles 3781 said:

If the ship underwent contraction as it approached light-speed, wouldn't the hydrogen atoms inside the ship get so squeezed together, that they underwent nuclear fusion, and blew the ship apart in a gigantic nuclear explosion?

 

Not for the pilot, the ship will be as ok as always for him... but he will see the rest of the universe doing so. If he has a certain sense of humor, he could call it the Big Bang 

It's a joke 🙂  I don't think that will happen, and if something, the Big Bang looks much more similar to what happens when the pilot decelerates and the 1 meter universe turns into a many billions light-year universe, expanding space-time and galaxies far faster than c, as the Lorentz-contraction losses effect 

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Do you consider Einstein to be correct?  He claimed that the speed of light is invariable.  Where's the evidence for that?  Don't our telescopes show show galaxies flying apart at many times the speed of light?

The thing is, you shouldn't get too fixated on an "authority figure" like Einstein. These "authority figures" have held up the progress of science in the past.

Like Aristotle.  He said that the planets must revolve in perfect circles.  They don't - they revolve in ellipses. But because Aristotle was an authority figure, he delayed the progress of astronomy for a thousand years.

Einstein looks like another authority figure - he says nothing can exceed the speed of light.  How does he know?   

 

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20 minutes ago, Winterlong said:

Not for the pilot, the ship will be as ok as always for him... but he will see the rest of the universe doing so. If he has a certain sense of humor, he could call it the Big Bang 

It's a joke 🙂  I don't think that will happen, and if something, the Big Bang looks much more similar to what happens when the pilot decelerates and the 1 meter universe turns into a many billions light-year universe, expanding space-time and galaxies far faster than c, as the Lorentz-contraction losses effect 

Very perceptive post.

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9 minutes ago, Charles 3781 said:

Do you consider Einstein to be correct?  He claimed that the speed of light is invariable.  Where's the evidence for that? 

Invariant c comes from Maxwell’s equations. The electromagnetic wave equation only works if c is invariant, and we know that EM waves are still waves when there is relative motion between source and receiver.

Plus, relativity works.

9 minutes ago, Charles 3781 said:

Don't our telescopes show show galaxies flying apart at many times the speed of light?

That’s from space expanding.

9 minutes ago, Charles 3781 said:

The thing is, you shouldn't get too fixated on an "authority figure" like Einstein. These "authority figures" have held up the progress of science in the past.

That’s not what’s going on. Relativity is accepted because it works. Really well.

9 minutes ago, Charles 3781 said:

Like Aristotle.  He said that the planets must revolve in perfect circles.  They don't - they revolve in ellipses. But because Aristotle was an authority figure, he delayed the progress of astronomy for a thousand years.

Einstein looks like another authority figure - he says nothing can exceed the speed of light.  How does he know?   

That what the well-tested theory says. And every time we test it, it passes.

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1 hour ago, Charles 3781 said:

If the ship underwent contraction as it approached light-speed, wouldn't the hydrogen atoms inside the ship get so squeezed together, that they underwent nuclear fusion, and blew the ship apart in a gigantic nuclear explosion?

Remember this is about relative measurements. The people (and atoms) on the ship will see no change.

And, from the point of view of the other observer, the atoms will be compressed as well so they never get close enough to fuse. (Having seen your later post: yes, we have evidence of this.)

18 minutes ago, Charles 3781 said:

Do you consider Einstein to be correct?  He claimed that the speed of light is invariable.  Where's the evidence for that?  Don't our telescopes show show galaxies flying apart at many times the speed of light?

The thing is, you shouldn't get too fixated on an "authority figure" like Einstein. These "authority figures" have held up the progress of science in the past.

Like Aristotle.  He said that the planets must revolve in perfect circles.  They don't - they revolve in ellipses. But because Aristotle was an authority figure, he delayed the progress of astronomy for a thousand years.

Einstein looks like another authority figure - he says nothing can exceed the speed of light.  How does he know?   

It is nothing to do with Einstein as an authority figure. It is purely about the evidence. The only reason he is considered an "authority" at all, is because the evidence confirmed most of his ideas. Not all though.

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1 hour ago, swansont said:

That’s from space expanding.

It's all relative. If you are in the part of space that is expanding then you can move faster than light then in reference to a part that isn't expanding.

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27 minutes ago, drumbo said:

It's all relative. If you are in the part of space that is expanding then you can move faster than light then in reference to a part that isn't expanding.

All space is expanding, and the limitation of c doesn’t apply to space.

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14 hours ago, Charles 3781 said:

Like Aristotle.  He said that the planets must revolve in perfect circles.  They don't - they revolve in ellipses. But because Aristotle was an authority figure, he delayed the progress of astronomy for a thousand years.

The difference is that Aristotle didn't do science in the modern sense of the word, his assertion was just a philosophical speculation. There was no evidence, and no way for him to really test the hypothesis. The theory of relativity is a completely different story - it is based upon the shortcomings of earlier models, and it is directly amenable to the scientific method, i.e. it can be tested and falsified. To date, it has been in full accord with every single experiment that has ever been thrown at it; no violations of relativistic principles have ever been observed anywhere, despite it having been extensively tested over the last 100+ years.

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20 hours ago, Charles 3781 said:

Do you consider Einstein to be correct?  He claimed that the speed of light is invariable.  Where's the evidence for that?  Don't our telescopes show show galaxies flying apart at many times the speed of light?

 

I'll give you a practical example from not too long ago. NASA had a mission which sent a pair of probes to an outer gas giant moon.  The probes consisted of an orbiter and a lander.

The lander would communicate its data to the orbiter, which then relayed it to the Earth.  A problem however occurred. The communication protocol between lander and orbiter required the data to be sent at a specific rate, and it turned out that there was a mismatch between the lander and orbiter which prevented them from talking to each other.   The "fix" involved using Doppler shift.  By adjusting the orbit of the orbiter, they created a "window" during which the Doppler shift effect between the two exactly canceled out the mismatch between the two.  The lander would dump all its data during these windows.

So how does this show the invariant speed of light?  If the speed of light is invariant, then the Doppler shift only depends on the Relative velocity between orbiter and Probe. Ergo, You only have to worry about the orbiter's orbit relative to the Moon.    If it were not invariant, then all the various motions of the Moon orbiting the Planet and Planet orbiting the Sun would also play a role in the determining the Doppler shift.  NASA would have had to factor all this in when working out their windows.   But they didn't. ( If they had, this would have been huge news, as it would have been a refutation of a prediction of Relativity.)

 

As for the  "Einstein as authority" argument.  Einstein would have disavowed it, as he was no fan of authority himself.

Relativity is held in high accord not due to any reverence for Einstein, but because it keeps passing every test thrown at it.    And we do continue to test it.  We test it for the very reason that we don't just accept it as "absolute truth", but are looking for any weaknesses it may have.   But as long as it keeps making accurate predictions, it will be treated as being the closest thing to "truth" we have.

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  • 2 weeks later...
On 8/9/2020 at 10:42 PM, swansont said:

All space is expanding, and the limitation of c doesn’t apply to space.

 Thanks swansont. You are always pithy.   But can "space" really "expand".   What does the word  "space" actually mean?

Is "space" an actual physical  "thing"  -  in the same sense that stars and planets are physical "things" .

The nouns "star" and "planet"  denote actual, solid, physical 3-dimensional objects.  Which have definite, measurable, and constant dimensions and mass.  So they are clearly "things".

But the noun "space"  just seems to be an abstract  word.  A kind of shorthand for: "the separation between objects".

Thus we can say: " Object A is separated from Object B by 1 metre" .  Or we can say:  "There's a space of 1 metre between Object A and Object B".

But  does this replacement of "is separated from"  by  "a space between",  make "Space" into a thing?

 

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56 minutes ago, Charles 3781 said:

  Is "space" an actual physical  "thing"  -  in the same sense that stars and planets are physical "things" .

No, which is why it can expand faster than c

It's also why things like a planet or a solar system don't expand - they are subject to forces that hold them together, despite the expansion

Quote

The nouns "star" and "planet"  denote actual, solid, physical 3-dimensional objects.  Which have definite, measurable, and constant dimensions and mass.  So they are clearly "things".

But the noun "space"  just seems to be an abstract  word.  A kind of shorthand for: "the separation between objects".

Similar to "distance" and "time" two other words representing abstractions. Fields, operators in a Hilbert space - physics is chock full of abstract words. Some reify these things, but they are not something you can hold in your hand, or kick (if you are a fan of Samuel Johnson)

 

Quote

Thus we can say: " Object A is separated from Object B by 1 metre" .  Or we can say:  "There's a space of 1 metre between Object A and Object B".

But  does this replacement of "is separated from"  by  "a space between",  make "Space" into a thing?

If you can hand me that meter of space, I will concede that it is a thing.

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38 minutes ago, Charles 3781 said:

Thanks swansont. You are always pithy.   But can "space" really "expand".   What does the word  "space" actually mean?

"Space" in this context means the distance between things (in three dimensions). And, yes, that distance really can increase as predicted by theory.

39 minutes ago, Charles 3781 said:

But the noun "space"  just seems to be an abstract  word.  A kind of shorthand for: "the separation between objects".

Yep.

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On 8/10/2020 at 11:02 AM, Markus Hanke said:

The difference is that Aristotle didn't do science in the modern sense of the word, his assertion was just a philosophical speculation. There was no evidence, and no way for him to really test the hypothesis. The theory of relativity is a completely different story - it is based upon the shortcomings of earlier models, and it is directly amenable to the scientific method, i.e. it can be tested and falsified. To date, it has been in full accord with every single experiment that has ever been thrown at it; no violations of relativistic principles have ever been observed anywhere, despite it having been extensively tested over the last 100+ years.

Thanks Markus.  I think you're a bit hard on Aristotle.  He did the best he could.  But he lived in an Ancient Greek world without telescopes.

So he can't really be blamed for espousing "circular" orbits.  Even Copernicus and Galileo, 1500 years later, concurred in the assumption of circularity in planetary orbits.  One can see why - the circle is symmetrically neater than Kepler's unexplained lop-sided ellipses.  Aristotle's biggest bloomer was claiming that the Earth and the Heavens were made of different stuff.

As for Relativity Theory,  has there been any practical test of it?  I don't mean measuring the masses of particles  in the LHC. In that machine, particle masses are calculated by employing  Relativity theory. So the results are bound to agree with the theory.

What I mean is, have any experiments been conducted with a rocket-ship accelerating away at near light-speed from the Earth, looping round Alpha Centauri, then coming back. And the crew getting out years younger than they should be.

Well obviously not.  In the present state of our technology we can't do it.  So isn't the idea just theory.  Where's the experimental verification?

 

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5 minutes ago, Charles 3781 said:

What I mean is, have any experiments been conducted with a rocket-ship accelerating away at near light-speed from the Earth, looping round Alpha Centauri, then coming back. And the crew getting out years younger than they should be.

Well obviously not.  In the present state of our technology we can't do it.  So isn't the idea just theory.  Where's the experimental verification?

You don't need to travel at near light speed or loop round Alpha Centauri. The effects happen at slower speeds and shorter distances. They are just smaller. But luckily, we can build instruments accurate enough to measure them.

There are a huge number of experimental confirmations of relativity (that is why it is a theory, i.e. a really solid and well tested explanation, rather than just a guess)

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

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

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26 minutes ago, Charles 3781 said:

As for Relativity Theory,  has there been any practical test of it?  I don't mean measuring the masses of particles  in the LHC. In that machine, particle masses are calculated by employing  Relativity theory. So the results are bound to agree with the theory.

What I mean is, have any experiments been conducted with a rocket-ship accelerating away at near light-speed from the Earth, looping round Alpha Centauri, then coming back. And the crew getting out years younger than they should be.

Well obviously not.  In the present state of our technology we can't do it.  So isn't the idea just theory.  Where's the experimental verification?

No, but you don't need to go that far. You can put clocks on planes and send them around the worldThat was done almost 50 years ago. Their level of precision allows smaller effects to be measured than ages of astronauts. More recently, it's clocks on satellites (e.g. GPS) 

Mass differences from a nucleus being in an excited state vs ground state has been measured. The frequency shift of atoms owing to their height in the gravitational field has been observed.

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33 minutes ago, Charles 3781 said:

 

As for Relativity Theory,  has there been any practical test of it?  I don't mean measuring the masses of particles  in the LHC. In that machine, particle masses are calculated by employing  Relativity theory. So the results are bound to agree with the theory.

To understand where your claim that accelerator results are essentially "fudged" is in error,  you need to look ar the history of accelerators.  One of the early types, the  cyclotron relied on the fact the accelerated particles took the same amount  of time to make one trip around no matter how fast they were moving, as they naturally went around in increasingly larger circles as they sped up

However, this only worked for so long, as relativistic effects began to take hold. The speed/radius ratio drifted apart at higher speeds. Thus the snychrotron had to be developed  to reach greater particle speeds. In other words,  if it hadn't been for Relativity rearing its head, cyclotrons wouldn't have the upper speed limit they do.

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3 hours ago, Charles 3781 said:

But the noun "space"  just seems to be an abstract  word.  A kind of shorthand for: "the separation between objects".

I assume you are familiar with the English language.

Nouns can be abstract.

This ability is one of the strengths of English as a language as it provides for more than one type of noun, and all that entails.

It is also a rational language, which means that there are things (trains of deductive thought) you can say in English that cannot be said in maths, ie mathematically.

Edited by studiot
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3 hours ago, Charles 3781 said:

But the noun "space"  just seems to be an abstract  word.  A kind of shorthand for: "the separation between objects".

And more than that, "the curvature of spacetime" is shorthand for "the curvature of the geometry of our measurements of space and time" (or something like that)

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20 minutes ago, Strange said:

And more than that, "the curvature of spacetime" is shorthand for "the curvature of the geometry of our measurements of space and time" (or something like that)

I've no idea what "the curvature of spacetime" means.  Nor, I suspect does anyone.  But - Einstein said it.  So will you "bow the knee"?

29 minutes ago, studiot said:

I assume you are familiar with the English language.

Nouns can be abstract.

This ability is one of the strengths of English as a language as it provides for more than one type of noun, and all that entails.

It is also a rational language, which means that there are things (trains of deductive thought) you can say in English that cannot be said in maths, ie mathematically.

You're absolutely right.  The English language is the most rational, and sophisticated, medium of linguistic communication ever devised.

I mean, can you imagine this forum being conducted in French.  What would that be like!

Is it any any wonder that almost all major scientific advances have been achieved by speakers of English.

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5 minutes ago, Charles 3781 said:

I've no idea what "the curvature of spacetime" means.  Nor, I suspect does anyone.  But - Einstein said it.  So will you "bow the knee"?

I have nearly a dozen books on my shelves devoted to curvature in Maths and Physics.

Most are highly technical, but this one should be accessible to you, the English translation (the Germnas seem particularly good at this subject) is highly readable and recommended with barely a math formula in sight.

Harald Fritzsch hold the chair of Theoretical Physics at Munich and is visiting Professor at Caltech and CERN.

For all that he is very readable.

Fritzsch1.jpg.71c11ddda21085069ee60772f5a2d50c.jpg

11 minutes ago, Charles 3781 said:

You're absolutely right.  The English language is the most rational, and sophisticated, medium of linguistic communication ever devised.

Thank you.

I should have added that there is nothing you can say in Mathematics you cannot say in English, but not the other way round.

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Thanks Studiot for your courteous reply.  Or are you taking the pass?  It doesn't matter. I have read loads and loads of books about Quantum Theory , Spacetime curvature, and all the rest. 

As a result, I have come to this conclusion:

Nobody really knows what the heck it's all about.

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50 minutes ago, Charles 3781 said:

I've no idea what "the curvature of spacetime" means.  Nor, I suspect does anyone.  But - Einstein said it.  So will you "bow the knee"?

It is shorthand for the mathematical description of the geometry we use to describe the effects of mass and energy. As you have already been told, it is nothing to do with "Einstein said it" or "bowing the knee"; it is all about how well the model matches observation (very well, indeed).

52 minutes ago, Charles 3781 said:

You're absolutely right.  The English language is the most rational, and sophisticated, medium of linguistic communication ever devised.

It is precisely no more and no less rational or sophisticated than another language.

52 minutes ago, Charles 3781 said:

Is it any any wonder that almost all major scientific advances have been achieved by speakers of English.

Obviously not true.

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1 minute ago, Strange said:

 

It is precisely no more and no less rational or sophisticated than another language.

Has the English language got a larger vocabulary than any other language?

Please cite another language  with a larger vocabulary.

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