3 minutes ago, Time Traveler said:

It seems I have disturbed many 'scientists' here. My apologies. I'll quit

Oh thank god, you had all our scientific dogma was circling the drain...

3 minutes ago, Time Traveler said:

It seems I have disturbed many 'scientists' here. My apologies. I'll quit

That's also how you ended your last thread on this topic.

Nobody is disturbed.

I remember many many years ago at school, sitting on the step of a building watching someone about 150m away bouncing a basketball on the footpath. Thanks to the brick wall of the building they were outside, I was also hearing the ball hit the concrete.

They stopped bouncing the ball. And I heard one more bounce. Slightly jarring at first.

The distance was such that (like watching a movie where they sync up visuals and sound and ignore reality) I was seeing and hearing the bounce at the "same time", but of course the sound of each bounce was getting to me later than the sight.

None of this is new.

20 minutes ago, Time Traveler said:

It seems I have disturbed many 'scientists' here. My apologies. I'll quit

How are you possibly disturbing and scientist here ???. Every scientist is well aware of the speed limit of information exchange or that it takes time for our brains to process information. It's absolutely nothing new. 

 

2 hours ago, Time Traveler said:

My point is that we will never observe simultaneity

Rookie mistake.
There is no such thing.

54 minutes ago, Time Traveler said:

It seems I have disturbed many 'scientists' here. My apologies. I'll quit

I think it’s “perturbed” and it’s from pointing to issues that we already know about and account for as if they are unknown, and somehow a problem. 

You might be befuddled by the ramifications of a finite speed of light but I assure you that others are not.

5 hours ago, Time Traveler said:

It seems I have disturbed many 'scientists' here. My apologies. I'll quit

It's disturbing that scientists have been accumulating human knowledge for quite some time now, but you refuse to take advantage of that, and prefer filling the gaps in your own knowledge with guesswork and jumped-to conclusions.

14 hours ago, Time Traveler said:

I am trying to understand ( my humble opinion is that  Big Bang theory is a nonsense) if someone smarter than me could explain if our universe was infinite all the time or was finite or wasn't at all  13.8 billions years ago . After that explanation I have other ask

Quite easily done but that's off topic in this thread. If you really want to understand Cosmology I will be more than glad to help but in a more suitable thread. However put simply our Observable universe will always be finite and we do not know beyond our Observable portion. It is equally possible being finite or infinite. The current datasets both are possible. 

Edited April 14, 20241 yr by Mordred

In case the Universe is finite, I can't understand how there is no center

Can someone smart and well informed+ well-meaning , give me light and tell me if the Universe is the place (vacuum) where all existing ( matter, energy, fields, dark energy , dark matter ) +  all who are inside the vacuum . If that is then the vacuum is infinite and all from inside could be finite or infinite ? In this case ,all from inside the vacuum at beginning of Big Bang had a place in infinite , like point 0 or place near point 0 on the intersection of the axes OX-OY-OZ . After time 0 when Big Bang happened was inflation ....That point 0 is then the center of all existing in the vacuum
If I am wrong I wait arguments against

 

39 minutes ago, Time Traveler said:

In case the Universe is finite, I can't understand how there is no center

Can someone smart and well informed+ well-meaning , give me light and tell me if the Universe is the place (vacuum) where all existing ( matter, energy, fields, dark energy , dark matter ) +  all who are inside the vacuum . If that is then the vacuum is infinite and all from inside could be finite or infinite ? In this case ,all from inside the vacuum at beginning of Big Bang had a place in infinite , like point 0 or place near point 0 on the intersection of the axes OX-OY-OZ . After time 0 when Big Bang happened was inflation ....That point 0 is then the center of all existing in the vacuum
If I am wrong I wait arguments against

 

I've already given a link to read about that, earlier in the thread. Have you read it? If not, why not? 

But if you want to pursue this subject I suggest you need to start a new thread about it, as it is a quite different topic from the title of this one. 

1 hour ago, Time Traveler said:

In case the Universe is finite, I can't understand how there is no center

Can someone smart and well informed+ well-meaning , give me light and tell me if the Universe is the place (vacuum) where all existing ( matter, energy, fields, dark energy , dark matter ) +  all who are inside the vacuum . If that is then the vacuum is infinite and all from inside could be finite or infinite ? In this case ,all from inside the vacuum at beginning of Big Bang had a place in infinite , like point 0 or place near point 0 on the intersection of the axes OX-OY-OZ . After time 0 when Big Bang happened was inflation ....That point 0 is then the center of all existing in the vacuum
If I am wrong I wait arguments against

 

If you stand in the middle of a salt flat, your horizon or how far you can see, is about three miles in every direction, from that perspective 'you' are always at the center of 'your' universe.

IOW the big bang is the salt flat and we're in the middle of it. And it doesn't matter what's outside of what we can see bc if we can't see it... 😉

IOW the middle just got bigger...

BTW we're all time travellers it's just another direction that we can't see, beyond 3 miles...😉

Edited April 14, 20241 yr by dimreepr

4 hours ago, Time Traveler said:

I can't understand how there is no center

Fun fact: The universe is under no obligation to make sense to uninformed human minds 

8 minutes ago, iNow said:

Fun fact: The universe is under no obligation to make sense to uninformed human minds 

Indeed, but we are under the obligation to teach the children, how to tell the difference...

I don't like Dimreepr's analogy, but I'll try to use it.

Picture yourself living on that salt flat, which is level as far as the eye can see, and seems to go on forever.
You start walking in one direction ( at a great speed ) and eventually you lose sight of the salt flat, and run into mountains and forests.
Even cities and bodies of water that you have to swim across ( again at great speed ) until eventually ( after quite a while ) you come back to the same exact spot on the salt flat. But from the opposite direction.
Clearly the surface of the world is finite; but there is no boundary.

So where is the center of the world's surface ???

Now ( and this is a big step ) extend your thinking to 4 dimensional intrinsically curved space-time.

16 hours ago, MigL said:

I don't like Dimreepr's analogy, but I'll try to use it.

Picture yourself living on that salt flat, which is level as far as the eye can see, and seems to go on forever.
You start walking in one direction ( at a great speed ) and eventually you lose sight of the salt flat, and run into mountains and forests.
Even cities and bodies of water that you have to swim across ( again at great speed ) until eventually ( after quite a while ) you come back to the same exact spot on the salt flat. But from the opposite direction.
Clearly the surface of the world is finite; but there is no boundary.

So where is the center of the world's surface ???

Now ( and this is a big step ) extend your thinking to 4 dimensional intrinsically curved space-time.

TBH I just thought a 2 dimensional model was more appropriate, in this case... 🤔

Edited April 15, 20241 yr by dimreepr

On 4/14/2024 at 11:02 PM, MigL said:

I don't like Dimreepr's analogy, but I'll try to use it.

Picture yourself living on that salt flat, which is level as far as the eye can see, and seems to go on forever.
You start walking in one direction ( at a great speed ) and eventually you lose sight of the salt flat, and run into mountains and forests.
Even cities and bodies of water that you have to swim across ( again at great speed ) until eventually ( after quite a while ) you come back to the same exact spot on the salt flat. But from the opposite direction.
Clearly the surface of the world is finite; but there is no boundary.

So where is the center of the world's surface ???

Now ( and this is a big step ) extend your thinking to 4 dimensional intrinsically curved space-time.

Surface is not volume ...a finite volume has a center ...if I accept to extend my thinking  from 2 dimensional to 3 dimensional , not 4 dimensional who is a wrong interpretation of our Universe, then You should admit the Zeno paradox is true ....Achilles and the Tortoise ...In a race, the fastest runner can never overtake the slowest, because the pursuer must first reach the point where the pursued started, so the slowest must always have the advantage.

44 minutes ago, Time Traveler said:

Surface is not volume ...a finite volume has a center ...

If all spatial dimensions loop back on themselves seamlessly, so that whichever direction you travel in, after n light years you are back where you started, then what does 'centre' even mean?

It's definitely finite with a volume oto (n light years)³. But there is no point more remote from the boundary than any other because there is no boundary. All points within the space are geometrically exactly equivalent.

23 hours ago, sethoflagos said:

If all spatial dimensions loop back on themselves seamlessly, so that whichever direction you travel in, after n light years you are back where you started, then what does 'centre' even mean?

It's definitely finite with a volume oto (n light years)³. But there is no point more remote from the boundary than any other because there is no boundary. All points within the space are geometrically exactly equivalent.

I am thinking at volume of space occupied of all atoms from our Universe... there is a center of mass of all atoms

31 minutes ago, Time Traveler said:

I am thinking at volume of space occupied of all atoms from our Universe

No, you’re not 

31 minutes ago, Time Traveler said:

there is a center of mass of all atoms

No, there isn’t 

 

The universe is under no obligation to make sense to our tiny ape minds, and it will continue operating exactly as it does and always has regardless of your personal inability to comprehend those operations accurately. 

While your username suggests travel across time, your basic stance here suggests time can stop. As it doesn’t, never has, and never will, your basic stance is absurd. 

3 minutes ago, iNow said:

No, you’re not 

No, there isn’t 

 

The universe is under no obligation to make sense to our tiny ape minds, and it will continue operating exactly as it does and always has regardless of your personal inability to comprehend those operations accurately. 

I agree with you with correction "...regardless of our collective inability.."

On 4/19/2024 at 2:27 PM, Time Traveler said:

Surface is not volume ...a finite volume has a center ...if I accept to extend my thinking  from 2 dimensional to 3 dimensional , not 4 dimensional

The reason you can 'picture' the 2dimensional surface of the sphere/world is because you ;ive in three dimensions.
To see a volume loop back on itself, you would need to live in 4 dimensions. The volume is effectively embedded in a higher dimensional manifold.
You cannot picture it, however, you can demonstrate it mathematically.

Space-time is a 4dimensional manifold, however, we have no need ( nor can they have any effect ) for embedding dimensions, so we call any topological curvature intrinsic, whereas an embedded topology would be extrinsic.

I think you've hit the nail on the head; failure to elevate your thinking is leading to your confusion.

Well,i have to say that his thread summoned members i never seen before.

oh,wait
its 1 year old.
Sorry my bad.

I realize my previous tone may have been sharp, and for that, I apologize. My perspective comes from 37 years of engineering, where mass balance and energy conservation are absolute. While I understand the mathematical models of spacetime, my focus is on the logical impossibility of 'double-counting' atoms in a closed system. I believe we are looking at the same reality from two different angles: one abstract-mathematical, one physical-energetic. Let's agree to disagree on the nature of the 'clock' versus the 'change'.

12 hours ago, Time Traveler said:

I realize my previous tone may have been sharp, and for that, I apologize. My perspective comes from 37 years of engineering, where mass balance and energy conservation are absolute. While I understand the mathematical models of spacetime, my focus is on the logical impossibility of 'double-counting' atoms in a closed system. I believe we are looking at the same reality from two different angles: one abstract-mathematical, one physical-energetic. Let's agree to disagree on the nature of the 'clock' versus the 'change'.

We can't, imagine a two dimensional character living in the clock, it can only say cuckoo when the big hand changes to being fully erect. 😉

13 hours ago, Time Traveler said:

I realize my previous tone may have been sharp, and for that, I apologize. My perspective comes from 37 years of engineering, where mass balance and energy conservation are absolute. While I understand the mathematical models of spacetime, my focus is on the logical impossibility of 'double-counting' atoms in a closed system. I believe we are looking at the same reality from two different angles: one abstract-mathematical, one physical-energetic. Let's agree to disagree on the nature of the 'clock' versus the 'change'.

Yes, in my experience on these forums a lot of relativity eccentrics - I won't say cranks - and QM eccentrics too have an engineering background. I suspect it is because much of engineering is a sort of apotheosis of c.19th physics, seeming to achieve mastery over nature. This view was shaken by the advent of relativity and QM in the early c.20th, which told us a number of uncomfortably counterintuitive things about nature. (I was in fact taught 1st yr 6th form physics by a brilliant teacher who claimed to be agnostic about the existence of molecules! His degree was in engineering and he was great - at classical physics. But we got a different teacher in the 2nd year.)

As Feynman said: "You don't like it? Go somewhere else! To another universe where the rules are simpler, philosophically more pleasing, more psychologically easy........I'm not going to fake it. I'm not going to tell you it's something like a ball bearing on a spring when it isn't. "

Common sense is not enough.

When I first started physics one of my earlier goals was to solve DE as an optical illusion. I realized early enough that doing so required mathematics and a good understanding of the FLRW metric and GR.

In those studies I learned a valuable lesson. Simply because something doesn't make sense to you doesn't mean its incorrect.

Its a lesson I carry on to this very day. More enough enough if one studies why the physics professional community states what they state there is always numerous supportive as well as counter arguments or methodologies supporting one theory or another.

To a layman this unfortunately gives a rather daunting task of sorting through. Though the effort of doing so with an open mind can lead one to learn a great deal.

The biggest challenge is avoiding any personal bias. Once you form a solid opinion of I feel it should be this way. One tends to close the book on examine other possibilities.

This goes for any physics theory or model. The effort to understanding why physics describes something a certain way always has very strong reasoning behind it and those reasons are typically best understood by studying the related mathematical proofs.

Its one reason I study not just mainstream models and physics but study numerous potential models or theories. You would be amazed that with enough studying how much something that originally sounded ridiculous starts to make sense.

One also discovers how truly interconnected one theory is to numerous others. A simple change in one theory can often have numerous ramifications of dozens of others.

Something many of our typical crackpot dont fully recognize.

There's a simple consideration no theory or model ever becomes considered mainstream physics without years of rigorous testing and years of sorting the best fit to observational evidence.

Eureka moments are typically something that only exists in movies. Theory and model building for a robust theory takes an incredible amount of work and whats often forgotten. One of the most valuable practices is that a good theorist should spend far more time proving his own theory wrong than he/she did in developing it.

Little hint here if one studies statistics and statistical mechanics. One discovers that a great deal of the more difficult terminology used in QM and QFT actually originates from classical statistics. Examples being superposition, correlation functions the list goes on. It does help pull a lot of the mystery out of QM.