Utopia and Time Travel

[Steve001]

What you are talking about is not what I am talking about.

If one wants to think of the universe as being constantly in a purely objective state, bringing relativity into that discussion is an attempt to move away from that.

Relativity is about how subjectivity explains its position within the universe which is (and I am quite positive those arguing it in relation to what I am saying KNOW this to be the case) a distraction away from that.



Which is why you didn't include the full context of my post with accompanying picture of the scientist holding a representation of the universe as an object, and my pointing out that the representation clearly shows one thing and that there is no reason why the one thing cannot be understood objectively as existing in its own time of perpetual nowness.

Perhaps you et al would actually like to address that rather than pretend it is a case of relativity?

Do you understand what the word "subjective" means when it's use to describe things happening relative to one another? True or not? You seem to be defining the word in the fashion of seeing a face in a cloud for example. One person sees a face one person does not. That's not the correct definition as it's use in relativity if that is how you understand it.

Explain this "nowness" term in plain language please.

 

[The Greater Fool]

Actually, it has to do with the time component. You didn't really answer the question, so I am not sure if you see where I am going with it. Do you agree that the speed of light is a constant, regardless of the reference frame?

Like most here, I am not the Theoretical Physicist, though I have done reading and have the knowledge of your typical janitor, but...

Sure, the speed of light is a constant.

 

[ferd burfle]

Which is why you didn't include the full context of my post with accompanying picture of the scientist holding a representation of the universe as an object, and my pointing out that the representation clearly shows one thing and that there is no reason why the one thing cannot be understood objectively as existing in its own time of perpetual nowness.



Perhaps you et al would actually like to address that rather than pretend it is a case of relativity?

Please feel free to imagine the universe however you wish.



Sent from my iPad using Tapatalk

 

[Navigator]

Please feel free to imagine the universe however you wish.

Nope. Just how it is.

 

[Navigator]

Do you understand what the word "subjective" means when it's use to describe things happening relative to one another? True or not? You seem to be defining the word in the fashion of seeing a face in a cloud for example. One person sees a face one person does not. That's not the correct definition as it's use in relativity if that is how you understand it.

Well now, all I am arguing is not the theory of relativity. You would know that if you read my posts...which...

Explain this "nowness" term in plain language please.

...apparently you don't, because the language I use is plain enough.

I even gave a picture. Go figure...

How 'plain' does language have to be before ya'll stop pretending like its too complicated?

 

[Roboramma]

Make it so one bomb going off first prevents the other bomb from exploding at all for an even more counterintuitive twist. One person lives and one dies, but who? Can we change our frame of reference and change the outcome?

Relativity, as I think you pointed out earlier, leaves causal relationships intact. If a signal can get from Dave after his bomb goes of to Cindy before hers does, then it will do so in all reference frames and which happened first will be unambiguous.

 

[Roboramma]

ETA: You are pressing me to decide which frame is the 'real' frame. You know better. Reality is what each of these frames of reference are peeking into.

I am pressing you to confront the inconsistencies in what you are saying. On the one hand you say a specific sequence is real, on the other you refuse to say what sequence that is, because you know that another sequence is just as real. Yet somehow you maintain that only one is the real sequence of events.

It's hard for me to understand how you don't see the logical contradiction here.

 

[Roboramma]

I believe all the foregoing demonstrate that reality happens in a specific way, in a specific sequence, otherwise frame of reference would change outcome.

The mathematics of special relativity (or you could say the geometry of Minkowski spacetime) is such that causation is left unaffected by the relativity of simultaneity.

 

[Roboramma]

I don't think I am describing Minkowski Space since you built SR frames of reference, then pushed me to choose one or the other as more real. Though, at first blush, perhaps it conveys the idea I am trying to get across, I'll have to read about it and reflect.

I think I might see some of the issue we are having here: I'm not RussDill, but when I asked you to choose between two reference frames to say which is the real one, it's because you said that there is some specific sequence of events in reality. That suggests that only one sequence is the real sequence, which means choosing one reference frame over another.

Instead, as I think you are correct to insist upon, there is an underlying reality which those reference frames are only arbitrary ways of describing. But that underlying reality is different from what you would expect. It is made up of spacetime events occurring in a 4D spacetime.

Let me try to use an analogy to help to get this across one more time:

Take two points in empty space. They can be abstract points or maybe they are pebbles floating in space. We look at them and see the reality that they are separated by some distance. That's the real thing. We can describe that by making a coordinate system (X,Y,Z) and plotting their location on that coordinate system. So, maybe pebble A is at the origin of our coordinate system and pebble B is located at X=2, Y=0, Z=0. Later I decide that this coordinate system isn't so useful to me so I use a different one in which A is at X = 2, Y= 0, Z=0, and B is at X = 2, Y = 2, Z = 0.

Someone else uses a coordinate system that's rotated relative to mine and puts A at the origin but B is at X= 2^1/2 Y = 2^1/2 Z= 0.

Drawing the pebble's locations on these three different systems they look a little different, but it's easy to see that they are describing the same reality: X and Y are separated by 1 unit of distance. Distance is the invariant property in 3D space.

But spacetime is 4 dimensional and it's geometry follows the Lorentz transformation. Taking a particular view of spacetime and rotating it leaves all the relationships (the reality that you refer to) intact, it also leaves all causal relationships intact, but it doesn't leave the order of events intact. It leaves neither the distance nor the time between two points in spacetime intact. Instead we have a new thing: the spacetime separation (or the proper time) that is the same no matter how you rotate your viewpoint. Is pebble A above, below, or level with pebble B on the Y axis? That depends on how you define your Y axis! But that pebble A is two units of distance away from pebble B doesn't depend on that definition: that is the reality of the situation.

Does event A happen before, after, or simultaneous with event B? That depends on how you define your time axis. But that Event A is located at a spacetime separation from event B of X meters is invariant. That's the reality.

Here's a picture: the reality is that A and B are X units away from each other in spacetime. No matter how much you turn this page that will remain true. But see what happens to the order of events is you start turning the page: A, which in this coordinate system happens first, will happen after B. Relative velocity = a rotation in reference frame.

 

[Roboramma]

The mathematics of special relativity (or you could say the geometry of Minkowski spacetime) is such that causation is left unaffected by the relativity of simultaneity.

An easy way to see this is to draw a simple spacetime diagram like the one I draw and put some events down on it. Light travels at 45 degrees. Realise that the speed of light is your speed limit and so you can't make rotations greater than 45 degrees. You'll find that all events which can be connected by 45 degree lines (or greater than 45 degrees) will keep their ordering intact after rotations of less than 45 degrees, whereas events connected by lines of less than 45 degrees may show up with their sequence different. Events that are connected by lines of less than 45 degrees cannot influence each other (because light travels on 45 degree lines and thus nothing travelling at or slower than the speed of light can get from one event to the other).

 

[The Greater Fool]

It's Monday morning for me, and I'm up against a deadline today so won't be able to devote the time I have been to this. I am getting repetitive again, anyhow.

I think I might see some of the issue we are having here: I'm not RussDill...

I apologize for any confusion. I try to deal with each post as they come and not rely on who previously said what (or in what order ).

... but when I asked you to choose between two reference frames to say which is the real one, it's because you said that there is some specific sequence of events in reality. That suggests that only one sequence is the real sequence, which means choosing one reference frame over another.

Only one sequence *is* real. It's just not one of the subjective SR frames.

Reality does happen a specific way, in a specific sequence. However, one can't simply choose an SR frame and declare that the [objective] [absolute] reality.

Instead, as I think you are correct to insist upon, there is an underlying reality which those reference frames are only arbitrary ways of describing. But that underlying reality is different from what you would expect. It is made up of spacetime events occurring in a 4D spacetime.

Let me try to use an analogy to help to get this across one more time:

Take two points in empty space. They can be abstract points or maybe they are pebbles floating in space. We look at them and see the reality that they are separated by some distance. That's the real thing. We can describe that by making a coordinate system (X,Y,Z) and plotting their location on that coordinate system. So, maybe pebble A is at the origin of our coordinate system and pebble B is located at X=2, Y=0, Z=0. Later I decide that this coordinate system isn't so useful to me so I use a different one in which A is at X = 2, Y= 0, Z=0, and B is at X = 2, Y = 2, Z = 0.

Someone else uses a coordinate system that's rotated relative to mine and puts A at the origin but B is at X= 2^1/2 Y = 2^1/2 Z= 0.

Drawing the pebble's locations on these three different systems they look a little different, but it's easy to see that they are describing the same reality: X and Y are separated by 1 unit of distance. Distance is the invariant property in 3D space.

I'm pretty sure we're in agreement to this point.

But spacetime is 4 dimensional and it's geometry follows the Lorentz transformation. Taking a particular view of spacetime and rotating it leaves all the relationships (the reality that you refer to) intact, it also leaves all causal relationships intact, but it doesn't leave the order of events intact. It leaves neither the distance nor the time between two points in spacetime intact. Instead we have a new thing: the spacetime separation (or the proper time) that is the same no matter how you rotate your viewpoint. Is pebble A above, below, or level with pebble B on the Y axis? That depends on how you define your Y axis! But that pebble A is two units of distance away from pebble B doesn't depend on that definition: that is the reality of the situation.

And we're back. I've highlighted the parts that indicate you are in an SR frame. You've built a reality, then confuse the description with the reality. At the bold part, you've hit the heart of the matter. Descriptions, models, and SR help us understand reality but they do not change that reality.

Does event A happen before, after, or simultaneous with event B? That depends on how you define your time axis. But that Event A is located at a spacetime separation from event B of X meters is invariant. That's the reality.

Again, "does A happen before B?" is trying to force a choice between SR perspectives.

Reality doesn't care how you model it, or from what SR perspective you examine it.

Here's a picture: the reality is that A and B are X units away from each other in spacetime. No matter how much you turn this page that will remain true. But see what happens to the order of events is you start turning the page: A, which in this coordinate system happens first, will happen after B. Relative velocity = a rotation in reference frame.

The page (reality) didn't change, just your SR frame.

 

[psionl0]

Reality is all encompassing.

Who's reality?

Why would the speed of light matter?

The mathematics in Einstein's theory of relativity says it does and every every testable prediction in this theory has been born out through experiment.

Choose two locations in spacetime 1 billion LY apart.

In which reference frame?

The speed of light has no impact on the two spacetime locations. They both are as they are.

It is time to stop saying that "relativity sounds like nonsense to me" and prove that relativity is wrong. Until you can do that, reality will always be relative to a reference frame.

 

[Roboramma]

ETA: This is probably obvious but, the below is in response to The Greater Fool's post #391.

Reality isn't dependent upon my choice of reference frame.

The ordering of events is dependent upon my choice of reference frame.

Therefore the ordering of events is not "reality".

Look at the picture I drew and you'll see clear as day that the picture can remain the same under rotations but the ordering of events doesn't. The picture is what's real, the arbitrary choice of time axis isn't, and therefore the ordering of events isn't the real thing. What's real is the entire spacetime. I'm sorry that this doesn't conform to your common sense.

 

[The Greater Fool]

Who's reality?

This illustrates the issue. We don't each get different realities, we get different perspectives of the same reality.

The mathematics in Einstein's theory of relativity says it does and every every testable prediction in this theory has been born out through experiment.

The speed of light matters not one whit to reality. Just like reality doesn't care about you or me or our perspectives. Light moves through reality. How fast matters to calculations that describe reality, but not to the reality itself.

In which reference frame?

In REALITY. You really think that your frame of reference changes the distance between two points in reality?

It is time to stop saying that "relativity sounds like nonsense to me" and prove that relativity is wrong. Until you can do that, reality will always be relative to a reference frame.

Then stop saying that, for certainly I have not. You don't seem to be reading what I am writing, so perhaps yours is a different reality.

 

[The Greater Fool]

ETA: This is probably obvious but, the below is in response to The Greater Fool's post #391.

Reality isn't dependent upon my choice of reference frame.

Just so.

The ordering of events is dependent upon my choice of reference frame.

More precisely, your perception of the order is dependent upon your reference frame. The reality you are framing is as it is.

Therefore the ordering of events is not "reality".

Your experience of the events (of reality) is not reality.

Look at the picture I drew and you'll see clear as day that the picture can remain the same under rotations but the ordering of events doesn't. The picture is what's real, the arbitrary choice of time axis isn't, and therefore the ordering of events isn't the real thing. What's real is the entire spacetime. I'm sorry that this doesn't conform to your common sense.

From my perspective, you posted the picture last night. Has it changed since then, or is it the same picture? I can change my perspectives, but that does not change the picture.

 

[psionl0]

In REALITY.

What is "REALITY"? Is that something different to "reality"?

 

[Crazy Chainsaw]

That's using the word change in a very odd way. Imagine both detectors are set up equidistant from the source. Depending on your chosen inertial frame of reference, it's a changing b, b charging a, or somehow they change each other at the same time

If one is a the other one has to be b, change a to b, the other one has to be a.
In theory you could send a probe to another planet, all day across the universe,
And transport something there though entanglement.

Entanglement is the key to Hawking Radiation.

 

[Roboramma]

More precisely, your perception of the order is dependent upon your reference frame. The reality you are framing is as it is.

You keep saying that, but when I ask you to show me what the real order of events is, you refuse to do so. I have shown how the ordering of events is explicitly dependent upon reference frame. You have asserted that there is some "real" ordering of events that isn't dependent upon reference frame but have not given any support for that assertion and won't even say what it is.

This is extremely well established science. It'd be nice if you could actually address what I'm saying.

 

[The Greater Fool]

What is "REALITY"? Is that something different to "reality"?

Wit. Wonderful.

 

[The Greater Fool]

You keep saying that, but when I ask you to show me what the real order of events is, you refuse to do so. I have shown how the ordering of events is explicitly dependent upon reference frame. You have asserted that there is some "real" ordering of events that isn't dependent upon reference frame but have not given any support for that assertion and won't even say what it is.

This is extremely well established science. It'd be nice if you could actually address what I'm saying.

I am addressing what you are saying. I can't tell you what sequence things happen in because any description I give is necessarily bound by SR.

The support of reality is bound up in every theory that attempts to describe it, including SR. Even in SR, reality is a given.

Look at every single example you have given to show me SR and frames of reference. In every single example, you have started with an objective reality.

Look at your paper... again. That is where your example started, and it represents a small piece of reality. Turn the paper (change your perspective) and look how each frame is different. Yet, the reality of the paper, our 'givens' remain unchanged. I'm asked which point is first. I say the paper remains unchanged.

We're talking past each other.