Utopia and Time Travel

[Roboramma]

BTW, check out a Penrose diagram for a black hole sometime. You have two regions of space for which it actually isn't possible no matter what angle you use to draw a line between what is happening "now" in the universe and what is happening "now" in the singularity.

Shouldn't that be "beyond the event horizon", or perhaps "inside the black hole"?

 

[RussDill]

Shouldn't that be "beyond the event horizon", or perhaps "inside the black hole"?

Yup, sorry. I think it might be even a bit fuzzier than that as certain world lines cannot escape a given region of space where a black hole is forming even before the event horizon forms.

 

[alexi_drago]

What - in your opinion is 'the nature of the universe"?




For the umpteenth time, it is not about the internal individual beings of consciousnesses point of view. They too are part of the nature of the universe, not the ones who get to say how the universe is as an holistic thing...and that being. "no it isn't" It sure is if the individual can place his position within it as irrelevant to that question and subsequent answer.

Obviously the universe has to be something as that holistic thing and in that one simply has to lay aside the theories of relativity as some kind of principle which explains the concept of universal now in terms of that whole universe. Those theories ONLY deal with the fact that individuals have subjective reference in relation to the whole, from within it. These are not in themselves wrong and should not in themselves be used as a measure of right or wrong in relation to the overall universe and its most obvious state of perpetual nowness ,moment to moment - undivided.

Address that. Because no one is arguing ToR is wrong. It has nothing to do with the idea of universal now. It is all about how individual perceive the universe from within the universe.

Saying that because no one can see the universe from outside of it, is no argument because we see enough of it to get the gist. It is one thing doing one thing, not a series of disconnected unrelated moments.

It's nothing to do with observers, its a property the universe has to have for this universal now to exist, there needs to be u universal rest with respect to something like an aether. Such a property may or may not exist, the universe may or may not exist in the way you think it does.

 

[Pixel42]

Can any instant not be counted from the Big Bang (as zero)?

The reference frame which is at rest relative to the cosmic microwave background is sometimes described as a preferred reference frame as it simplifies matters, but it's no more valid than any other according to relativity. Similarly a reference frame in which the sun is motionless makes life simpler when considering the motion of the planets, whilst one in which it is moving makes life simpler when considering the rotation of the galaxy.

https://en.m.wikipedia.org/wiki/Preferred_frame

https://medium.com/starts-with-a-bang/how-fast-are-we-moving-through-space-985bf470378d#.9m2dskuxy

 

[The Greater Fool]

Well, if it is not real, then what is its relevance to our universe? All kinds of logical constructs or abstract ideas can be conceived of or imagined, but that doesn't mean they are applicable to reality. The nature of reality sets bounds to what is possible. I can imagine the concept of a universal restframe or an observer outside of our universe or the smell of purple. But none of them are part of reality.

Have fun explaining SR without an objective frame.

Purple smells like a little blue and a little red, obviously. See Synesthesia

It's amazing to me that the universe doesn't happen objectively, only subjectively.

 

[Roboramma]

Have fun explaining SR without an objective frame.

Purple smells like a little blue and a little red, obviously. See Synesthesia

It's amazing to me that the universe doesn't happen objectively, only subjectively.

There is no "objective" reference frame in special relativity, if by that you mean a reference frame that is somehow more real than any other.

There are some things which are reference frame dependent, for example whether or not two events are simultaneous. There are also things that are invariant: they will be the same in all reference frames. For instance the proper time between two events.

That two events can't be said to be objectively simultaneous doesn't mean that they don't exist or even that we can't say anything about the relationship between them. It just means that we can't say how much of their separation is space and how much of it is time. We can say whether they are space-like or time-like separated, however.

For instance, if any observer sees two events as simultaneous, then they are space like separated. This means that there will necessarily be a reference frame in which A happens before B and another in which B happens before A.

If it's possible for something to travel from event A to event B then they are timeline separated and there will be a reference frame in which they are in the same place but only separated in time, and others in which they are separated by both space and time. But all observers will agree about the proper time between them.

There's a simple analogy in newtonian physics: imagine I'm standing on the ground watching someone on a train as it passes. He is dribbling a basket ball. From my perspective every time the ball hits the train it is landing at a different point in space, whereas from his perspective it is hitting the same point. Which of us is right?

 

[marplots]

There's a simple analogy in newtonian physics: imagine I'm standing on the ground watching someone on a train as it passes. He is dribbling a basket ball. From my perspective every time the ball hits the train it is landing at a different point in space, whereas from his perspective it is hitting the same point. Which of us is right?

I am.

 

[The Greater Fool]

There's a simple analogy in newtonian physics: imagine I'm standing on the ground watching someone on a train as it passes. He is dribbling a basket ball. From my perspective every time the ball hits the train it is landing at a different point in space, whereas from his perspective it is hitting the same point. Which of us is right?

I'm not disagreeing with SR at all.

In this final example, is there one ball bouncing? It is doing what it is doing when it is doing it, regardless how the observers see it.

If it is completely observer dependent, then how are you sure they are seeing the same bouncing ball?

The answers are you built on objective frame to illustrate the subjective (SR) frames.

 

[marplots]

I'm not disagreeing with SR at all.

In this final example, is there one ball bouncing? It is doing what it is doing when it is doing it, regardless how the observers see it.

If it is completely observer dependent, then how are you sure they are seeing the same bouncing ball?

The answers are you built on objective frame to illustrate the subjective (SR) frames.

Exactly. One reality, different points of view.

 

[Roboramma]

I'm not disagreeing with SR at all.

In this final example, is there one ball bouncing? It is doing what it is doing when it is doing it, regardless how the observers see it.

Yes, and all observers agree that there is one ball.

If it is completely observer dependent, then how are you sure they are seeing the same bouncing ball?

It isn't completely observer dependant. There are things that all observers will agree on. They can also calculate what the results in other frames. The results of any measurement are very clear.

The answers are you built on objective frame to illustrate the subjective (SR) frames.

I don't think you even know what a reference frame is.

 

[William Parcher]

The monument works as a sun dial precisely because it is moving relative to the sun. Specially it is its 24-hour cycle of revolutions around the earth's axis that is being measured by a sun dial.

Back to the sundial conversation.

I was talking about the monument moving on earth which it doesn't do because it's an 81,000 ton stone. If it did move around on earth then it wouldn't work very well as a sundial because you would constantly have to recalibrate its dial.

Sorry for revisiting this now, as the thread has moved away from this topic.

 

[Roboramma]

Back to the sundial conversation.

I was talking about the monument moving on earth which it doesn't do because it's an 81,000 ton stone. If it did move around on earth then it wouldn't work very well as a sundial because you would constantly have to recalibrate its dial.

Sorry for revisiting this now, as the thread has moved away from this topic.

Right, but you were also using it as an example of something that can tell time without moving, and I was pointing out that it is it's motion (relative to the sun) that is being measured when we use it to measure the passage of time.

 

[The Greater Fool]

Yes, and all observers agree that there is one ball.

It isn't completely observer dependant. There are things that all observers will agree on. They can also calculate what the results in other frames. The results of any measurement are very clear.


I don't think you even know what a reference frame is.

Perhaps Marplots explains it better:

Exactly. One reality, different points of view.

 

[Roboramma]

Perhaps Marplots explains it better:

Sure, and there are some things that depend on one's point of view and others that don't.

For instance, "How fast is that thing moving?" is not a property of reality; "How fast is that thing moving relative to that other thing" is. "When did that happen?" is not a property of reality; "what is the proper time between these two points" is.

Some things are properties of reality and some things depend on one's point of view, and you are making mistakes about which is which.

 

[The Greater Fool]

Sure, and there are some things that depend on one's point of view and others that don't.

For instance, "How fast is that thing moving?" is not a property of reality; "How fast is that thing moving relative to that other thing" is. "When did that happen?" is not a property of reality; "what is the proper time between these two points" is.

Some things are properties of reality and some things depend on one's point of view, and you are making mistakes about which is which.

Perhaps I am. Perhaps I am just not explaining myself in the terms you accept. Let me change some words:

Reality is. Reality was. Reality will be. Reality happens. Reality continues to happen. Reality is there, things are happening, whether there is an observer or not. These things that happen in reality happen in a sequence.

We, observers, cannot observe reality in the whole, we can only logically construct (imagine) what is happening in all of reality, or in the parts we can perceive.

Thus, to explain SR, we construct a piece of reality, a ball bouncing on a moving train. It's a model, a construct. Now, we use SR to explain what observers in different places travelling at different speeds relative to the constructed reality.

Now, I get SR and how reality appears to us. It is still a small view of the ever present, greater reality.

You seem to choke when I call (imagining) the entirety of reality an objective frame of reference, so don't call it that. Call it the entirety of reality as it exists, though 'objective view' I should think would cover it. Call it whatever you want when you describe the actual motion of a bouncing ball on a moving train.

 

[Donn]

Sure it can. And where are you counting?

I dimly see. I am saying, relative to me, there is a moment ... Now! That the entire universe must be in. But it is from my pov.

 

[Pianoro]

Purple smells like a little blue and a little red, obviously. See Synesthesia

Point conceded.

Reality is. Reality was. Reality will be. Reality happens. Reality continues to happen. Reality is there, things are happening, whether there is an observer or not. These things that happen in reality happen in a sequence

Yes, reality happens and things happen whether there is an observer or not. In any given reference frame events happen in a sequence. In another reference frame, they may happen in a different sequence. In our world, time is dependent on the reference frame and all of them are equally valid. It's very counterintuitive but it is the nature of reality as we observe it.

You seem to choke when I call (imagining) the entirety of reality an objective frame of reference, so don't call it that. Call it the entirety of reality as it exists, though 'objective view' I should think would cover it. Call it whatever you want when you describe the actual motion of a bouncing ball on a moving train.

How would you define a frame of reference?

 

[Pianoro]

I dimly see. I am saying, relative to me, there is a moment ... Now! That the entire universe must be in. But it is from my pov.

That sounds good to me.

 

[The Greater Fool]

Yes, reality happens and things happen whether there is an observer or not. In any given reference frame events happen in a sequence. In another reference frame, they may happen in a different sequence. In our world, time is dependent on the reference frame and all of them are equally valid. It's very counterintuitive but it is the nature of reality as we observe it.

Actually, that we perceive reality different seems very intuitive to me. I think the part that is counter-intuitive is that I am having a difficult time getting folks to accept that reality is out there and does NOT depend on observers to be reality.

While two observers my experience the same events in a different sequence, in reality (objective frame] the events happened in a particular way, in a particular sequence.

How would you define a frame of reference?

Without looking it up and giving a dictionary or wiki definition:

[ Reference ] **
A point of view, perspective;
The point of reference for observation;
The angle / scope of a scene;

As examples, we have the ball on the moving train, and the different 'frames of reference' of the person bouncing the ball, the person on the outside of the train, and the person in a jet. All perceive the ball moving in a different way because of their perspectives and the quirks of SR.

AND, in this scene, you and I have a frame of reference: We are describing the reality of the ball on the train, because we have a "god's* view" of the scene. In fact, like god*, we created (describe) the [objective] scene. The reality with the other frames of reference we describe.

In describing SR we also necessarily take a "god's* view" (the Objective Reality) to set the scene.

No one can experience the objective reality. But we can describe it. Hence why I say it is not real, it is an image.





* There is no god. However, god being omniscient would experience reality as it is, since there would be no SR since god is everywhere, all the time (sorta like Starbucks).

** Get it? 'reference' in a [ ] frame

 

[Hokulele]

The point is, there is no one, single "objective" frame of reference. You can choose the Big Bang as a time point of reference, or you can choose the creation of earth. Both are equally valid. As was mentioned earlier, is there a universal "up"?