# Requirement for two "nows" to grasp the idea of Simultaneity

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2 hours ago, tar said:

You can't have c unless you have time remaining the same and distance remaining the same.  If the distance.shortens then light would cover the span in a quicker time.  This would invalidate the statement that light speed is invariant.

The distance shortens by the same factor as the time, leaving c the same.

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4 hours ago, tar said:

beecee,  What I am arguing here is that the results from various experiments align with the equations of SR and GR but there are other ways to explain the results than to suggest that time dilates and distances shorten.

Start explaining. Start by explaining to me why we need to plug in SR with regards to GPS satellites, and then the muon effect.

4 hours ago, tar said:

c is the distance light travels in a particular time.  You can't have c unless you have time remaining the same and distance remaining the same.  If the distance.shortens then light would cover the span in a quicker time.  This would invalidate the statement that light speed is invariant.   What I suggest is happening is that people do not switch properly between two frames of reference. You can for instance be in the same inertial frame but distant from another observer or from a part of the experiment.

"c" is actually the speed of light in a vacuum and is obviously constant. It has been shown irrefutably [not withstanding your yet to be announced examples to the contrary] that it is space/length and time that are invariant. And of course, at least in my puny mind, as we go faster, time slows down [dilates] while "c" is constant. Just as space and time are interchangeable, so to is length contraction and time dilation.

4 hours ago, tar said:

My example of the pulsar proves my argument.   You cannot have the next pulse in a second unless the light wave you are going to see in a sec is right now existing in space 186,000 miles from here.

No it doesn't. You can never be sure that the next pulse will ever happen. We see Alpha Centauri tonight in our now. That "now" happened 4.3 years ago from the FoR of Centauri. There are many many nows that will see different things. My "now" when I see Alpha Centauri tonight is not the "now" of any planet orbiting Alpha Centauri, because that "now" does not exist as far as I am aware, until I receive information [light] about it.

4 hours ago, tar said:

The other now is real, things are actually happening outside our view, because the light has not reached us yet, but we know they have to be happening now because we see them later.  This other now is the universal now that for any one observer has to be imagined as happening now for an observer in those other locations.

How can you know you will see them later?

4 hours ago, tar said:

Experiments have to consider this other now.  Everything we see in space has already actually happened.  That is if we see a quasar filled with first generation stars we can know in our imaginations that right now, in that area of space, there is likely a galaxy like the Milky way, or Andromeda filled with third generation stars.

We of course will never see it because the light from the current situation is billions of years away. and we don't live that long, but that does not mean it is not what is happening now in that are of space where we see the quasar.

Well the correct part is that yes, everytime we look into the night sky, we are looking into the past. That literally means that it may not actually be there. We have no information about their "now".

Edited by beecee
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20 hours ago, swansont said:

The distance shortens by the same factor as the time, leaving c the same.

Except time shortening has no meaning.

Distances shortenining has no meaning.

Kant thought there were two a priori understandings, that needed no, in fact had no definitions or components.  Those two were time and space.  Everyone knows what time is and everyone knows what space is.

It makes no sense to say that time shortens or space shortens.  It has no meaning.  All to balance an equation.  Senseless.

no one knows what spacetime is

no one responded to my thought experiment

have the traveling twin count the pules of a pulsar

have the stay at home count

have the twins compare their count upon the return of the traveling twin

any blue or red shift experienced by the traveling twin of the pulses will exactly reverse on the trip back

the count will be the same because the traveling twin never left the galaxy

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10 minutes ago, tar said:

Except time shortening has no meaning.

Distances shortenining has no meaning.

It does if you want to do anything related to time and distance.

Perhaps the most famous example of time dilation's impact on the modern world is that it has to be accounted for in order for GPS to work. Without it, no GPS. So it would seem that it does have an impact.

We can't measure length at the same precision as time, but there are examples of length contraction having an impact, too. Certain high-energy collision physics must take it into account. We have the well-known muon decay example. It's critical in order to explain why parallel, current-carrying wires exert forces on each other.

10 minutes ago, tar said:

Kant thought there were two a priori understandings, that needed no, in fact had no definitions or components.  Those two were time and space.  Everyone knows what time is and everyone knows what space is.

It makes no sense to say that time shortens or space shortens.  It has no meaning.  All to balance an equation.  Senseless.

no one knows what spacetime is

I think this translates to it makes no sense to you, and you don't know what spacetime is, but to project that onto other people is quite something.

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a 45 degree line exists only on your mental graph

imagine the incorrect transformations that are done when someone is trying to set one thing in the place of another and describing a four dimensional thing on a two dimensional media

my contention is that the mind deals with an idea as happening all within ones view or imaginary view

that however is not how the universe works

the universe is intricate beyond comprehension, huge beyond comprehension,  long lived beyond comprehension

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13 minutes ago, tar said:

a 45 degree line exists only on your mental graph

We use such aids to understanding in a lot of ways, and in lots of disciplines. As they say, the map is not the territory. But maps are useful.

15 minutes ago, tar said:

imagine the incorrect transformations that are done when someone is trying to set one thing in the place of another and describing a four dimensional thing on a two dimensional media

my contention is that the mind deals with an idea as happening all within ones view or imaginary view

that however is not how the universe works

But where has the science failed? Do you have any concrete examples of relativity not working as advertised?

15 minutes ago, tar said:

the universe is intricate beyond comprehension, huge beyond comprehension,  long lived beyond comprehension

Again, you are projecting your own lack of comprehension on to others. We may not know everything, but that's very different from saying we know nothing.

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19 minutes ago, swansont said:

It does if you want to do anything related to time and distance.

Perhaps the most famous example of time dilation's impact on the modern world is that it has to be accounted for in order for GPS to work. Without it, no GPS. So it would seem that it does have an impact.

We can't measure length at the same precision as time, but there are examples of length contraction having an impact, too. Certain high-energy collision physics must take it into account. We have the well-known muon decay example. It's critical in order to explain why parallel, current-carrying wires exert forces on each other.

I think this translates to it makes no sense to you, and you don't know what spacetime is, but to project that onto other people is quite something.

could you describe spacetime, using space and time as the a priori understandings?

I do not understand Chinese, although a 3 year old Chinese kid does.

That does not mean I do not understand reality.

Math is a language.  One thing stands for another.

My question to you, is can the forces between two wires be explained with magnetic and electric fields, without using muon decay?

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6 minutes ago, tar said:

My question to you, is can the forces between two wires be explained with magnetic and electric fields, without using muon decay?

Muon decay has nothing to do with this beyond being another example of relativity

My point was that you can explain the magnetic force with only the electric force and relativity. Because, in fact, all the classical magnetic force is is an electrostatic force viewed from a moving frame of reference, via the relativistic transformations. But you knew this, right? Because such criticism has to be based on a thorough understanding of relativity

Quote

I do not understand Chinese, although a 3 year old Chinese kid does.

That does not mean I do not understand reality.

Physics isn't attempting to explain reality. It's explaining how nature behaves.

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4 minutes ago, swansont said:

We use such aids to understanding in a lot of ways, and in lots of disciplines. As they say, the map is not the territory. But maps are useful.

But where has the science failed? Do you have any concrete examples of relativity not working as advertised?

Again, you are projecting your own lack of comprehension on to others. We may not know everything, but that's very different from saying we know nothing.

I believe relativity has failed in constructing dark energy and dark matter from the motion of a super nova in another galaxy.

I believe relativity has failed in proposing other realities and other dimensions that have no bearing on our reality.

I believe relativity has failed in causing people to think the universe is strange and not comprehensible, when everything actually fits together and works quite flawlessly.  I do not yield to you that yiou have it right and I have it wrong.

57 minutes ago, swansont said:

It does if you want to do anything related to time and distance.

Perhaps the most famous example of time dilation's impact on the modern world is that it has to be accounted for in order for GPS to work. Without it, no GPS. So it would seem that it does have an impact.

We can't measure length at the same precision as time, but there are examples of length contraction having an impact, too. Certain high-energy collision physics must take it into account. We have the well-known muon decay example. It's critical in order to explain why parallel, current-carrying wires exert forces on each other.

I think this translates to it makes no sense to you, and you don't know what spacetime is, but to project that onto other people is quite something.

Perhaps,  but I try and read and understand QED and GR and SR stuff.  I have developed my own understanding of what makes sense and what does not.  Usually, if something is true it is true  in more than one way.  That is, you could sync GPS clocks without using relativity equations, using only distance and light travel time.  I f the orbiting clock runs slow or fast you apply the needed correction.

40 minutes ago, swansont said:

Muon decay has nothing to do with this beyond being another example of relativity

My point was that you can explain the magnetic force with only the electric force and relativity. Because, in fact, all the classical magnetic force is is an electrostatic force viewed from a moving frame of reference, via the relativistic transformations. But you knew this, right? Because such criticism has to be based on a thorough understanding of relativity

Physics isn't attempting to explain reality. It's explaining how nature behaves.

well suppose you have a pen pal on a planet circling a nearby star, where light travel time separates your nows by 3 years. When you get a message from her you know she sent it 3 years ago.  If she was 36 when she wrote it, you know she is 39 now.  Two nows.  When she gets your reply she will be 42.

She is, in reality only one age, as you are only one age.  And you increment your years at the same time.

20 hours ago, beecee said:

Start explaining. Start by explaining to me why we need to plug in SR with regards to GPS satellites, and then the muon effect.

"c" is actually the speed of light in a vacuum and is obviously constant. It has been shown irrefutably [not withstanding your yet to be announced examples to the contrary] that it is space/length and time that are invariant. And of course, at least in my puny mind, as we go faster, time slows down [dilates] while "c" is constant. Just as space and time are interchangeable, so to is length contraction and time dilation.

No it doesn't. You can never be sure that the next pulse will ever happen. We see Alpha Centauri tonight in our now. That "now" happened 4.3 years ago from the FoR of Centauri. There are many many nows that will see different things. My "now" when I see Alpha Centauri tonight is not the "now" of any planet orbiting Alpha Centauri, because that "now" does not exist as far as I am aware, until I receive information [light] about it.

How can you know you will see them later?

Well the correct part is that yes, everytime we look into the night sky, we are looking into the past. That literally means that it may not actually be there. We have no information about their "now".

Yes but our now includes light from alpha Centauri which it has for many past nows.  Although we can not be certain there is not a gamma ray burst that will hit the Earth on Tuesday on its way, we can be absolutely sure that in our now that occurred a minute ago, there was light from Alpha in space a light minute out because we just saw it.

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42 minutes ago, tar said:

I believe relativity has failed in constructing dark energy and dark matter from the motion of a super nova in another galaxy.

I believe relativity has failed in proposing other realities and other dimensions that have no bearing on our reality.

Relativity is why we think there is dark eneregy and dark matter. What has failed to happen is for some new theory to emerge to explain these things.

How does it fall to relativity to propose other realities and other dimensions?

42 minutes ago, tar said:

I believe relativity has failed in causing people to think the universe is strange and not comprehensible, when everything actually fits together and works quite flawlessly.  I do not yield to you that yiou have it right and I have it wrong.

What "I" have is a theory that has passed every experimental test thrown at it. What have you got? From this perspective you have nada.

42 minutes ago, tar said:

That is, you could sync GPS clocks without using relativity equations, using only distance and light travel time.  I f the orbiting clock runs slow or fast you apply the needed correction.

That was tried early on. Clocks were left uncorrected and were observed to not be running at the correct rate. The relativity corrections were correct to about 1%

Why would there be "needed corrections" if relativity were wrong?

42 minutes ago, tar said:

well suppose you have a pen pal on a planet circling a nearby star, where light travel time separates your nows by 3 years. When you get a message from her you know she sent it 3 years ago.  If she was 36 when she wrote it, you know she is 39 now.  Two nows.  When she gets your reply she will be 42.

She is, in reality only one age, as you are only one age.  And you increment your years at the same time.

We already know and adjust for light travel time; it's part of clock synchronization. "Now" is not a value that ever gets used when you try and quantify such things. "Now" is pretty useless for a wide swath of applications of relativity. That you are not aware of these applications doesn't make them any less real.

55 minutes ago, tar said:

I don't see what the pulsar "experiment" has to do with the validity of relativity. You have a distant pulsar, you have a bunch of pulses that are en route. Is there something more than that?

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2 hours ago, swansont said:

Relativity is why we think there is dark eneregy and dark matter. What has failed to happen is for some new theory to emerge to explain these things.

How does it fall to relativity to propose other realities and other dimensions?

What "I" have is a theory that has passed every experimental test thrown at it. What have you got? From this perspective you have nada.

That was tried early on. Clocks were left uncorrected and were observed to not be running at the correct rate. The relativity corrections were correct to about 1%

Why would there be "needed corrections" if relativity were wrong?

We already know and adjust for light travel time; it's part of clock synchronization. "Now" is not a value that ever gets used when you try and quantify such things. "Now" is pretty useless for a wide swath of applications of relativity. That you are not aware of these applications doesn't make them any less real.

I don't see what the pulsar "experiment" has to do with the validity of relativity. You have a distant pulsar, you have a bunch of pulses that are en route. Is there something more than that?

why yes

relativity equations would have the traveling twin not age as much as the stay at home

the pulsar cycle count experienced by both the stay at home and the moving twin would be exactly the same, thus invalidating the relativity equation

any differences in the clocks of the moving and stationary observers can be explained by red shift and blue shift where the frequency of light changes, not distance or the speed of light or time

Matter of fact, if you travel at relativistic speeds the universe in front of you is highly blue shifted and is hitting you with tremendous energy and the universe behind you is highly red shifted and visible light is hitting you as microwaves and radio waves.  Gamma rays coming in your front window, radio waves out the back.  On the way back the traveling twin will see the approaching clocks running fast, making up for any slow count on the way out.

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3 hours ago, tar said:

I believe relativity has failed in constructing dark energy and dark matter from the motion of a super nova in another galaxy.

I believe relativity has failed in proposing other realities and other dimensions that have no bearing on our reality.

I believe relativity has failed in causing people to think the universe is strange and not comprehensible, when everything actually fits together and works quite flawlessly.  I do not yield to you that yiou have it right and I have it wrong.

!

Moderator Note

OK, help me out here. You're not asking questions anymore, you're claiming "relativity has failed in X" without supplying any science to support yourself. You know you can't just wave your hands or appeal to incredulity. This should be moved to Speculations, but that won't help if you aren't willing to offer more support. You're soapboxing pretty much here, and ignoring replies that you've asked for.

If you want to stay in mainstream, listen to the mainstream replies you're getting and respond accordingly. If you want to defend your beliefs in Speculations, then please provide some science to support the stances.

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3 hours ago, tar said:

I believe

I believe

I believe

I have developed my own understanding

Some people also still believe the Earth is flat; or that the Earth is only 10,000 years old. That's pseudoscience and nonsensical and going totally against all that has been scientifically evidenced.

Newton also developed his own understandings by standing on the shoulders of giants of the past.

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9 minutes ago, tar said:

why yes

relativity equations would have the traveling twin not age as much as the stay at home

the pulsar cycle count experienced by both the stay at home and the moving twin would be exactly the same, thus invalidating the relativity equation

any differences in the clocks of the moving and stationary observers can be explained by red shift and blue shift where the frequency of light changes, not distance or the speed of light or time

Matter of fact, if you travel at relativistic speeds the universe in front of you is highly blue shifted and is hitting you with tremendous energy and the universe behind you is highly red shifted and visible light is hitting you as microwaves and radio waves.  Gamma rays coming in your front window, radio waves out the back.  On the way back the traveling twin will see the approaching clocks running fast, making up for any slow count on the way out.

This effect, which I  untis an obvious consequence of high velocity toward or away from an electromagnetic wave is a new theory evidently because you say I am wrong and I am not. I believe that is the way the universe works.

It is hard for me to accept a heat death of the universe because the whole universe is sending photons toward every other part of the universe.  Said photons don't disappear until they hit another atom an raise an electron into a higher energy state.  Then as atoms do they try to lose the energy by emitting a photon.  No atom can reach a ground state because the rest of the universe is sending its energy in to it

so i do not think the universe will suffer a heat death

3 minutes ago, Phi for All said:
!

Moderator Note

OK, help me out here. You're not asking questions anymore, you're claiming "relativity has failed in X" without supplying any science to support yourself. You know you can't just wave your hands or appeal to incredulity. This should be moved to Speculations, but that won't help if you aren't willing to offer more support. You're soapboxing pretty much here, and ignoring replies that you've asked for.

If you want to stay in mainstream, listen to the mainstream replies you're getting and respond accordingly. If you want to defend your beliefs in Speculations, then please provide some science to support the stances.

How is blue shift and red shift not science?

I will be quiet.

You are not answering honestly.  You are answering with the relativity equation, like it is more real than reality.  Reality makes more sense than how you say it works.

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9 minutes ago, tar said:

You are not answering honestly.  You are answering with the relativity equation, like it is more real than reality.  Reality makes more sense than how you say it works.

!

Moderator Note

So, you're saying that mainstream explanations aren't "honest"? I'm not sure that worldview will work out on a science discussion forum.

Since you're only going to get replies you're only going to ignore, I'm not leaving this open in Physics. Since you reject mainstream explanations overall wrt relativity, it's pointless to move this to Speculations, so I'm just going to close it. Two pages should be enough to show others where the trustworthy reasoning is.

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