Utopia and Time Travel

Navigator said:
I don't buy yer BS sorry peps. If the universe exists as one thing then it has an overall now.

So cut the crap about the subjective relativity theories proving this is not the case.
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Until you can prove that relativity is wrong and demonstrate where it is flawed, I am going to continue to believe that Einstein is right and you don't know which end you are talking from.
 
Most of modern physics is counterintuitive. There are many people who insist that their intuition is a better guide to the true nature of the universe than the tested and verified discoveries of humanity's greatest minds. The word for such people is 'crackpot'. Arrogance seems to be their defining feature.
 
Navigator said:
If yas' cannot answer my straightforward question just admit it instead of 'explaining' to me that it is beyond my ability to understand.
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No one is saying it's beyond your ability to understand. Here's the awesome thing about special relativity, it's super accessible to the layman. Not lessening Einstein's genius here, but I think many people upon learning about special relativity wonder why someone didn't come up with it sooner. The truth is that it was incredibly hard for people to let go of their preconceived notions and intuition and just follow the path laid out by experimental results.

I think people's frustration comes from your refusal to even attempt to understand. Your response has simply been, "no, you are wrong and I am right" rather than attempting to address anything with substance.
 
RussDill said:
No one is saying it's beyond your ability to understand. Here's the awesome thing about special relativity, it's super accessible to the layman. Not lessening Einstein's genius here, but I think many people upon learning about special relativity wonder why someone didn't come up with it sooner. The truth is that it was incredibly hard for people to let go of their preconceived notions and intuition and just follow the path laid out by experimental results.
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It doesn't require the kind of advanced maths or theoretical groundwork that makes general relativity or quantum physics so inaccessible to lay people.

I was given an introductory text to special relativity and I was surprised just how able I was to understand it.
 
Could this now business go like this:
Earth has many time zones, and yet we all experience our own 'now' moments from second to second?

It may be 15:48 right now for me, and 12:02 for you. Whether your time is before or later, can we not speak of a slice of the state of the entire earth at time t as being now?

Does this earth analogy not scale to galaxies and the universe?

(It's useless and none of us can agree or even decide on the schedule of events, to be sure.)

Here's another analogy:
I am alive, my heart is beating now. An astronaut's heart is also beating now, on a spaceship. An alien mollusc a trillion light years away is also alive, its heart is also beating now.
The watches and time-frames will all be whatever, but the fact of the moment itself, all the state of all the stuff as it is, that's surely real?

I don't pretend to know what Navigator is on about, pretty much ever, but this now thing is a neat conundrum.
 
Roboramma said:
Let's try to define a "now", and see if we can do it.

So I'm standing in a field, and off in the distance I see a boy playing with his dog. He throws a ball, and the dog goes and gets it. While watching this scene I'm tossing a rock up and down in my hand. At some particular moment, I see the ball leave his hand and feel the rock leave my hand. So, at first I think "These two events were simultaneous."

But then I remember that the speed of light is not infinite, it took time for the light from the ball to reach my eyes. No problem, I can account for that: I just calculate how long it took the light from the ball to reach my eyes and note that the ball left his hand that long before the rock left mine. Say he is 100m away: the ball left his hand 100m/c seconds before the rock left my hand. Of course I also have to take account of the fact that it takes time for the signal from the nerves in my hand to reach my brain (and similarly for my eyes), but again that's just some simple calculations. This done, I can write down a coordinate system and show when various events happened with relation to each other. Some events will be simultaneous but separated by space, others will be separated by time, some, of course, will be separated by both space and time.

In this way, standing in that field, I can make a coordinate system for the universe and say when events happen relative to each other.
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Roboramma said:
The Greater Fool said:
Based on Navigator's statements, I interpret the "Universal Now" to be the objective state of the universe at a given instant.

SR explains how observers would subjectively experience this objective universe.
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Do you think my last post gives a good way of defining that "universal now"?
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Yes, I think it does, specifically the bold/red. At least, my interpretation of the 'universal now.'

It really is just a logical construct, similar to the first paragraph building a logical scenario to illustrate SR. You state as part of the scenario that things objectively occur in a particular way.

The 'universal now' is a similar logical construct that says that in a particular instant, the universe is in particular state, and in the next instant, it is in a particular state. Just as you or I experience the now from instant to instant. It can't be observed, just logically described.

This 'universal now' does not conflict with SR, it's merely the logical stage in which SR operates.
 
The Greater Fool said:
This 'universal now' does not conflict with SR,
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I'm pretty sure it does.

From the Wikipedia article on Relativity of simultaneity:
According to the special theory of relativity, it is impossible to say in an absolute sense that two distinct events occur at the same time if those events are separated in space.
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Donn said:
Could this now business go like this:
Earth has many time zones, and yet we all experience our own 'now' moments from second to second?

It may be 15:48 right now for me, and 12:02 for you. Whether your time is before or later, can we not speak of a slice of the state of the entire earth at time t as being now?
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What kind of time zones are you thinking about? :D But seriously, if you are in London and it is 3pm and I am in New York and it is 10am and I drop my mug of coffee then this happens both in my "now" and your "now". That we measure the time of the day differently (time zones) has no effect on this.

However, as per special relativity, every observer must measure and map their own set of events that happen "now" just like Roboramma explained a little bit further up the thread. When two observers are in relative motion to each other, these sets will be different, and different events will be on their plane of simultaneity.

Thus, our "nows", as in the coffee mug example, align for practical purposes only. Because we move very slowly relative to each other, our planes of simultaneity are very similar and their actual misalignment is negligible. This applies for all people on Earth. In practice there is a "universal now" on Earth that all human observers can agree on.

Donn said:
Does this earth analogy not scale to galaxies and the universe?
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It does not. The misalignment of the planes of simultaneity becomes much greater at faster relative motion. It also becomes greater at greater distances.

Imagine yours and my plane of simultaneity each as a two-dimensional plane in three-dimensional space centered on each of us. Because, on a cosmic scale, we are pretty much in the same location, so are the centres of the planes. Now consider that they are at a very, very slightly different angle. In close proximity to both of us (e.g. the Earth) the difference is so small as to be negligible. But as you move farther and farther away, the small difference in angles starts to bring the planes farther and farther apart. Even if you are only moving relative to me at a modest speed (say, you are driving by in a car), at great distances (say another galaxy) the planes are so far apart that what happens in your "now" in that galaxy could actually be a day in the future for me (for example).

RussDill said:
The truth is that it was incredibly hard for people to let go of their preconceived notions and intuition and just follow the path laid out by experimental results.
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It was indeed. For the longest time people considered the idea of time not being universal as absurd and it really is very counterintuitive. Navigator's intuition is not worse than Newton's, it's just that long and careful work has shown that our intuition does not reflect reality in this case.
 
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Pixel42 said:
Most of modern physics is counterintuitive. There are many people who insist that their intuition is a better guide to the true nature of the universe than the tested and verified discoveries of humanity's greatest minds. The word for such people is 'crackpot'. Arrogance seems to be their defining feature.
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Well well well.

The universe does not exist as a whole thing in spacetime because 'crackpot'

Learn the fallacy of name-calling is not valid argument. The great and mighty theories from the minds of humanities finest intellects should never be used to endorse the expression of stupidity. It defeats the purpose of good use of intelligence.

If you have no answer except to claim 'because it cannot be seen to be happening by the greatest minds of humanity, then it cannot be happening and anyone who thinks otherwise is a 'crackpot' then you invoke fallacy.

Lift your game Pixel42
 
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Navigator said:
Essentially why can we NOT think of the universe as all its parts moving in a state of simultaneous perpetual nowness, when it most obviously must be doing just that in order for it to be ONE thing?
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Because in the universe we live in, time is not universal and independent of the observer. No "now" can be defined for the universe that is not dependent on an observer.

Since you have brought this up a few times, consciousness has nothing to do with this. "Observer" really just means "reference frame" here.
 
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Navigator said:
If you have no answer except to claim 'because it cannot be seen to be happening by the greatest minds of humanity, then it cannot be happening and anyone who thinks otherwise is a 'crackpot' then you invoke fallacy.
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The difference between the greatest minds in history and your mind is that the greatest minds in history don't just rely on personal rationalizations. They do the mathematics. They observe, hypothesize, test, refine and repeat.

So as well as using their intelligence which is superior to yours, they do a lot more work than you do.
 
RussDill said:
No one is saying it's beyond your ability to understand. Here's the awesome thing about special relativity, it's super accessible to the layman. Not lessening Einstein's genius here, but I think many people upon learning about special relativity wonder why someone didn't come up with it sooner. The truth is that it was incredibly hard for people to let go of their preconceived notions and intuition and just follow the path laid out by experimental results.

I think people's frustration comes from your refusal to even attempt to understand. Your response has simply been, "no, you are wrong and I am right" rather than attempting to address anything with substance.
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This is not even true! How am I supposed to accpet the good judgment of individual when they make such untruthful statements?

I have asked questions which have not been answered. I understand the basics of observers at different points etc - I explained that this in itself didn;t appear to say that the universe wasn't one thing, I am told that time exists as a dimension of space, so since spacetime is where the universe exists, and since the universe is one thing, then the universe should thus be in a constant state of perpetual now regardless of where in the universe anyone (or anything) is.

That is logical yes? Yet I am continually told it is not so and when I ask why that is not so, I am told it is not so because those within the universe observe it differently.

Wow! Solid! Not.
Why? Because it doesn't matter about those within the universe - they are PART of that one thing, and their position within it, while not the same as anyone else's position within it, (and thus relativity theories) this in itself does not mean that all time is in a perpetual state of now and thus the universe is - as one complete thing - is in a perpetual state of now and all the objects (not the consciousness of the objects) that together make up the universe are simultaneous in relation to that now...
 
Donn said:
Could this now business go like this:
Earth has many time zones, and yet we all experience our own 'now' moments from second to second?

It may be 15:48 right now for me, and 12:02 for you. Whether your time is before or later, can we not speak of a slice of the state of the entire earth at time t as being now?

Does this earth analogy not scale to galaxies and the universe?

(It's useless and none of us can agree or even decide on the schedule of events, to be sure.)

Here's another analogy:
I am alive, my heart is beating now. An astronaut's heart is also beating now, on a spaceship. An alien mollusc a trillion light years away is also alive, its heart is also beating now.
The watches and time-frames will all be whatever, but the fact of the moment itself, all the state of all the stuff as it is, that's surely real?

I don't pretend to know what Navigator is on about, pretty much ever, but this now thing is a neat conundrum.
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That's basically the gist of it. It isn't about the observer.

IF
the universe would still exist even without conscious beings within it:
(yes? no?)
THEN
[If yes] - the universe as one thing (all its parts together) must exist in a perpetual state of now,
[If no] - ...

the observer who does exist within it as a point of reference is just a part of the universe and just because the observer has a particular referrence point does not mean that the universe parts therefore do not all move together in a perpetual state of simultaneous now.
 
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JesseCuster said:
I'm pretty sure it does.

From the Wikipedia article on Relativity of simultaneity:
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I dont think it does exactly, if a true universal rest frame exists (in which you would be able to measure absolute position of events in space and time as well as use it as a reference for other frames ) it will be indistinguishable from any other frame of reference and can be treated no differently. Which is where this problem is, there is nothing about any frame of reference to say whether its the universal reference frame or not.
It has no place in relativity but i don't think it's contradictory.
 
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JesseCuster said:
I'm pretty sure it does.

From the Wikipedia article on Relativity of simultaneity:
According to the special theory of relativity, it is impossible to say in an absolute sense that two distinct events occur at the same time if those events are separated in space.
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Edit after my reply, to late to edit mine...

Your quote cuts out some quite interesting and clarifying details, largely concerned with observer frame experience, as SR typically does.

The 'universal now' does not claim that any specific events absolutely occurred at the same time. It is a claim that at any specific instant, the universe is in a specific state. In the next instant, it is in another specific state. There is no claim that the entire state can be observed, merely that it is. No observation, no frames of reference.

Observing the universe is a different kettle of fish, described by SR.

If you look at the little pictures on your wiki article, you will see even they show a specific state, and the various observations that yield different results.
 
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