Relation of time and speed of light

[swansont]

All of reality is a little bit larger than the earth

Which misses the point being made.

 

Assuming things to be true locally is very different from assuming them to be true everywhere.

 

It's not just an assumption, though. Again, missing the point.

[Thorham]

but why are there interaction forces in the first place?

 

But why do these mechanisms 'exist'?

 

These questions ultimately lead lead to questions that can't really be answered, but is it so bad to ask why, while we haven't reached that point yet?

 

First you have this 'if' as I highlight above. But then why should Universe be logical and be described by mathematics?

 

Why it's logical may or may not be answerable. I certainly don't know.

 

but 'why' mathematics works people debate and it is a philosophical question.

 

Why mathematics works, and why the universe appears to function in a logical manner are two different questions. Why mathematics works is easy: It's because the universe seems to work in a logical manner. Why the universe works in that way is the much harder question, and may not ever be answerable.

 

This is true, but we need to be careful by what you mean by 'local' and 'everywhere'.

 

Local would be the 'product of the big bang', if you can call it that, and non-local would be everywhere else.

 

So we take it as a working assumption that we can take physics and apply it to any part of our observable Universe. Of course this may not be the case and some observation could over throw this. Everyone accepts this, but right now there is no reason not to think that the laws of physics are universal.

 

I couldn't agree more, except for the word universal, because that implies everywhere, and not just locally. Seems to be a language issue.

 

Back to the opening post... we know that general relativity is a good model (or framework) to describe the gravitational physics of the Solar System. We also know that general relativity is good for other astrophsyical phenomena (i.e. gravitational waves), and we think that it is a good framework for cosmology.

 

Yes, undoubtedly. It just sounds like nay saying to me when people say certain things are impossible, and I don't like that. Saying that the speed of light is the maximum speed while we don't know all of reality is one of those things.

 

Also, seemingly legitimate scientists are trying to find out if you can't go faster anyway, so saying it's unknown doesn't seem unreasonable.

[Strange]

Also, seemingly legitimate scientists are trying to find out if you can't go faster anyway, so saying it's unknown doesn't seem unreasonable.

 

 

By that definition, everything is "unknown". Which is why your comments are ridiculous.

[Thorham]

It's not just an assumption, though. Again, missing the point.

 

It's a very reasonable assumption based on evidence. Perhaps it's just a wording problem.

[Strange]

 

It's a very reasonable assumption based on evidence. Perhaps it's just a wording problem.

 

 

An assumption isn't based on evidence, by definition.

[ajb]

I think this may more-or-less be a problem with langauge.

 

'Why' suggests some reason or purpose. This is not really something we can answer in physics. What we can do us present models and calculations therein to describe what we observe, and of course make further predictions. This I think is the closest to 'why', but really is is closest to 'how'.

 

So we do not know 'why' the speed of light is a local maximum speed limit, what we do know is that this feature is present in our best physical theoreis and that this agrees well with all observations/experiments made so far. This is the closest to 'impossible' as it gets in physics.

 

 

It's a very reasonable assumption based on evidence. Perhaps it's just a wording problem.

It is an assumption that seems reasonable and so far seems a good assumption in that it works, so far. If some evidence came to light that physics is not universal, in the sense that we expect it to work in our Observable Universe, then we would revise this assumption. So far there is no real evidence for us to rethink this assumption, but people do think about it.

[Thorham]

An assumption isn't based on evidence, by definition.

You're right. I looked it up in the dictionary.

 

'Why' suggests some reason or purpose. This is not really something we can answer in physics. What we can do us present models and calculations therein to describe what we observe, and of course make further predictions. This I think is the closest to 'why', but really is is closest to 'how'.

Yeah, that makes sense. Human language ain't easy.

[TakenItSeriously]

Sort of... information cannot be transmitted by any means faster than the speed of light. For instance, using quantum entangelment does not allow faster than light communication. In this sense, the speed of light defines causality.

Actually, there is an example of how entanglement can transmit useful information instantaneously over distance.

 

Say Bob and Alice were at the opposite receiving ends of a stream of entangled particles.

 

Bob observes the stream of particles as a series of 1s and 0s that he puts together to create a truly random binary key he uses to encrypt his emails that he sends to Alice.

 

Alice instantly receives the key and uses it to decrypt Bobs messages.

 

Therefore Bob did send Alice useful information that she (and only she) can use can use to decrypt his messages.

[Delta1212]

That's not really instantaneously sending information from Bob to Alice. That's sending information from a third point that reaches Bob and Alice at the same time, transmitted at light or sub-light speeds.

[swansont]

Actually, there is an example of how entanglement can transmit useful information instantaneously over distance.

 

Say Bob and Alice were at the opposite receiving ends of a stream of entangled particles.

 

Bob observes the stream of particles as a series of 1s and 0s that he puts together to create a truly random binary key he uses to encrypt his emails that he sends to Alice.

 

Alice instantly receives the key and uses it to decrypt Bobs messages.

 

Therefore Bob did send Alice useful information that she (and only she) can use can use to decrypt his messages.

 

 

emails are not instantaneous.

[TakenItSeriously]

emails are not instantaneous.

True but the encryption key that could decrypt the email was shared instantaneously.

Edited June 12, 2016 by TakenItSeriously

[Delta1212]

 

 

emails are not instantaneous.

He's saying you could use the correlated data to derive a key for the encryption that is developed on Bob's end.

 

It's essentially the same as saying that because you immediately know what the other person measures, that that information was transmitted instantly, which is obviously not how it works.

[swansont]

Any conclusion that information was transmitted instantaneously contains flawed reasoning.

[TakenItSeriously]

emails are not instantaneous.

Encryption Key example:

The useful, instantaneous information at a distance I was speaking of in that example was the encryption key they shared and know one else could have any knowledge of, including the man in the middle. Pun intended.

 

However, an even better example is the one given in the EPR paradox which stands for the last initials of it's authors: Albert Einstein, Boris Podolsky, and Nathan Rosen.

 

EPR Paradox summary:

It was based upon a mental model of an electron/positron entangled pair that involved the Heisenberg Uncertainty Principle.

 

The gist of it was:

given two properties of X-spin and Z-spin Uncertainty guarantees we cannot know the state of both properties at the same time even if separated by entangled particles.

 

Therefore if Alice received an electron and spontaneously decided to measure either the X-spin or the Z-spin of the electron, than at any point after that:

 

Bob attempted to measure, by chance, the opposite property from Alice (X/Z, Z/X) of the positron his result would always be inconclusive with a 50:50 probability for either + or -.

 

Or...

 

If Bob, by chance, chose to measure the same property as Alice (X/X or Z/Z), Than he would detect its state of + or - with 100% probability.

 

Therefore Bob could always deduce which measurement (X or Z) Alice chose to make instantly after she made it despite the distance that separated them.

 

The Authors of the article then acknowledged that one of two things must be true:

 

*Alice violated the speed of light by instantly communicating which measurement she just made to Bob over a distance.

 

or...

 

*Quantum Mechanics as not a complete theory and some missing portion of the theory must involve properties within each particle that are hidden from our domain.

 

*Note: I paraphrased those conclusions for clarity sake. You can Wikipedia the original quotes under "EPR Paradox"

 

As to the question of the usefulness of a single bit of information a couple of famous examples come to mind.

 

Paul Revere communicating the approach of the British at the beginning of the US Revolution by shining lamps from a light house "one if by land, two if by sea" as the song goes.

 

If your not a US citizen than another famous single bit communication example would be the grey or black (or is it white or black?) smoke that signals that cardinals [un]successful voting in of a new pope.

 

Note:

While this is only a mental model, according to the Wikipedia article, experiments had later verified the mental experiment as valid.

[Strange]

You seem to be forgetting the small detail that EPR were wrong.

[TakenItSeriously]

You seem to be forgetting the small detail that EPR were wrong.

That's news to me and I didn't see that mentioned in the Wikipedia article either.

 

Can you provide a reference?

Edited June 12, 2016 by TakenItSeriously

[Strange]

Actually, what they were wrong about was their conclusion that quantum theory must be incomplete because there is a correlation between non-local measurements. Bell's inequality shows that no theory with local hidden variables can produce the same results as quantum theory (and, therefore, reality).

[michel123456]

Hello again.

 

I have a question about why time slows down the faster your going, and why time will not let you go faster then light. Now my reason for this question is that Steven Hawkings says that if your on a vehicle, that's moving near the speed of light, and someone on board were to run towards the direction the vehicle is traveling, time will slow down EVEN more so that they aren't moving faster then light. My question is WHY does time slow down? I understand that speed is how far you travel in a period of time, so time slowing down prevents you from going faster then light. I also understand the reason you can't get something to go faster then light, is that since nothing GOES faster then light, then nothing can push you faster then light. You can't even get to the speed of light because force is mass times acceleration (why isn't it speed?). That means if your moving closer to the speed of light it won't be pushing you as hard as it as in the beggining, making your acceleration slower and slower until it will amount to nothingband you aren't getting any closer to the speed of light. So that's what I understand, but why would time slow down the faster you go, and why doesn't the universe want you going faster then light?

Why?

Because Spacetime looks like being a "single entity".

When time slows down, length contracts.

For my simple mind who likes simplicity, it means the upper part of the equation is changed by the same amount as the down part.

You have velocity v=d/t. When d decreases, t decreases also. Leaving v unchanged. It happens because v is the "thing". d and t are parts of v.

An analogy would be a marshmallow. If you squeeze it in one direction, it will expand in the other.

 

Now, why does it happen when v reaches the value of c, I don't know.

The other thing that trouble me very much is that v, by definition, is a relative value. No matter its value.

Edited June 13, 2016 by michel123456

[imatfaal]

...Now, why does it happen when v reaches the value of c, I don't know.

 

v - when it is standing for the velocity of a massive object - never reaches c. It approaches c but a massive object can not travel at the speed of light.

 

...The other thing that trouble me very much is that v, by definition, is a relative value. No matter its value.

 

This is very much why the whole thing works. What is always worth bearing in mind is that everything in one's own frame of reference remains normal, AND that the speed of light is always invariant; if you put these together then special relativity is almost the only possible answer and it is by far the simplest with the fewest additional assumptions.

[TakenItSeriously]

Actually, what they were wrong about was their conclusion that quantum theory must be incomplete because there is a correlation between non-local measurements. Bell's inequality shows that no theory with local hidden variables can produce the same results as quantum theory (and, therefore, reality).

Local hidden variables don't necessarily require inequality as Bell views it. What if the hidden variables were differential instead?

 

For example, consider a differential signal pair. Differential signals are equals and opposites, or put another way, they are identical signals that are phase shifted by 180⁰.

[swansont]

Local hidden variables don't necessarily require inequality as Bell views it. What if the hidden variables were differential instead?

 

For example, consider a differential signal pair. Differential signals are equals and opposites, or put another way, they are identical signals that are phase shifted by 180⁰.

How does that matter, and how would that manifest itself with, say, an entangled spin state? Let's see your analysis.

[TakenItSeriously]

How does that matter, and how would that manifest itself with, say, an entangled spin state? Let's see your analysis.

Is that allowed in these forums? I wouldn't mind but wouldn't it be considered speculation?

[swansont]

Is that allowed in these forums? I wouldn't mind but wouldn't it be considered speculation?

We have a speculations section.

[TakenItSeriously]

We have a speculations section.

Ok, but the issue is, I could only provide the logical model, the formalism would require too long a learning curve on my part, though mostly it would only require logical states. If your still interested in seeing the model, I could spend some time cleaning up a more presentable synopsis, for the QM portion.

 

BTW, there's a gravity loop portion in addition to this that I'm still trying to muddle my way though.

 

Edit to add: the model does resolve entanglement paradox, but it also solves or begins to explain most of the duality issues as well.

Edited June 14, 2016 by TakenItSeriously

[Raider5678]

Ok, but the issue is, I could only provide the logical model, the formalism would require too long a learning curve on my part, though mostly it would only require logical states. If your still interested in seeing the model, I could spend some time cleaning up a more presentable synopsis, for the QM portion.

BTW, there's a gravity loop portion in addition to this that I'm still trying to muddle my way though.

Edit to add: the model does resolve entanglement paradox, but it also solves or begins to explain most of the duality issues as well.

As long as it solves everything the current model solves, and then some, it might work. At least that's the current criteria.