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In a block universe we can describe an object using a function: F(x,y,z,t) Now, let’s take a brand new empty universe and add to it an object:

F(x,y,z,t)

We know everything about that object, so, no surprise, no dices. Now, let’s add another object:

G(x,y,z,t)

At this point F() must change because the new presence. The same happens to G().

Can I say that when a new object is added, the block universe changes/reconfigures itself?

UPDATE, 4 Jun

Time ago we worried about the idea that waves and particles are distinct objects. Can space and time act in the same way? It seems that we are not free to move as we wish in space and time, the faster you move in space, the slower you move in time. So, does time AND space exist? It seems that space-time is proven to exist.
I thought: if a particle can be a wave, is it possible that space-time can be more time or more space under some condition? I'm sure that my last sentence can make no sense at all, however, it's just for the idea.

Do you know the double-slit experiment? It seems that anything is everywhere, even in time. We fire particles and talk about waves, it weirdo, is it not? Something that is perfectly located, the particle, actually acts as something that is not well located at all: a wave.

Where is the wave on a guitar string? Everywhere. Where is the electron-wave in the universe? Everywhere. (Am I wrong saying that? )

In the current graphs, we are using x,y,z, and t. And to me, it seems a good way to say that space and time are everywhere in the universe. This is the start point of my curiosity.

Honestly, I'm scared to post my original question again on that group, so, let me ask: do the above sentences make sense to you?

ozw1z5rd
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    This is vague. What are these functions supposed to mean? Also, a universe could have non-interacting objects that do not affect each other. – G. Smith Jun 01 '21 at 22:47
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    Thinking about a block universe that changes is missing the point, in my opinion. – G. Smith Jun 01 '21 at 23:01
  • G.Smith: yes, I agree. If anything is defined and anything should be a function of x,y,z and t. it does not make sense at all. But is it so bad the idea that it can change?

    "What are these functions supposed to mean" --> world lines.

     – ozw1z5rd Jun 04 '21 at 08:48
  • @ozw1z5rd: Honestly, your question does not make much sense to me. This does not mean that you might not have a good intuition behind it. The problem is that physics is mainly centered around mathematics, and intuition is also necessary, but builds on that. The math behind your question is rather obscure, so it is difficult to tell anything about intuition relating to it. – oliver Jun 04 '21 at 14:08
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    The update is about different topics than the original post. These really belong in separate questions. The wave-particle duality is a separate thing from combining space and time into space-time. My answer to What carries the information for the Pauli exclusion principle to occur? explains some about waves vs particles. So does How can a red light photon be different from a blue light photon? – mmesser314 Jun 04 '21 at 14:09
  • Yes, space and time are different things. But they are different from what your everyday experience leads you to expect. They are more alike than you would expect. It does make sense to combine them into a 4D space-time. I explained some of this in this answer to Time dilation. Why?. – mmesser314 Jun 04 '21 at 14:18
  • Oliver you right, I’m lacking a good background and an intuition without that can’t be clear or useful. Can you suggest me some books to read? – ozw1z5rd Jun 05 '21 at 07:46
  • mmesser: interesting post, on which books did you study? – ozw1z5rd Jun 05 '21 at 07:48

2 Answers2

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What does "add another object" mean? What does "the block universe changes/reconfigures itself" mean? These are rhethorical questions. A block universe is something that does not change and you cannot add anything to.

All we can say is that if universes $F$ and $G$ are solutions to some sort of nonlinear physical equations, $F+G$ will usually not be a solution to those equations, due to nonlinearity/interaction. Suppose you knew an abstract "add" operation $\circ$ that allows you to determine a "combined" solution $F\circ G$ from the prior solutions $F$ and $G$, this would allow you to distinguish alternative physics from fantasy. But the application of $\circ$ by you does not happen in time (or does it?), so it is not meaningful to talk about the universe reconfiguring. Instead, you are testing alternative hypotheses about what really happened/happens/will happen in the universe, eternally.

oliver
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  • "But the application of ∘ by you does not happen in time (or it does)" I think that "time" is strongly connected with human experience and the human experience was wrong in several cases. It seems we can see that time elapsed when we notice some changes. – ozw1z5rd Jun 04 '21 at 08:41
  • A block universe is something that does not change and you cannot add anything to. -> ok, let's take 2 block universe A & B. Let's put the same electron in A & B and an extra electron in B. now let's write the world lines for those electrons in these universes. – ozw1z5rd Jun 04 '21 at 08:50
  • As to the "meaning of time": Everything in physics is also connected to subjective experience, which is why we have introduced measurements. And the measurements of physical time is unequivocal. That is no contradiction to subjective time being perceived differently, nor does it preclude any more sophisticated future understanding of physical time. – oliver Jun 04 '21 at 13:49
  • @ozw1z5rd: As to the "extra electron in B": Most people believe that our universe is unique, which the block universe perfectly represents, because everything is given from attosecond one. How can you add something to a unique universe? You can't! You can only add something if there are laws of physics, that allow other, alternative universes too. But then, doing physics amounts to telling whether a given hypothetic universe is one compatible with this physics or not (in the case of deterministic physics), or specifying how probable a given hypothetic universe is (in probabilistic physics). – oliver Jun 04 '21 at 13:59
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It is a common view that relativity requires the Block Universe. See What is time, does it flow, and if so what defines its direction?. But it isn't really true.

Part of the common sense view of time is that it flows. The present is all that exists. The future hasn't happened yet. The past is over and gone.

We think of time as absolute. A time $t_0$ uniquely identifies a slice of space-time. When t0 is now, all events in that slice have their moment of existence. The state of the universe is uniquely specified by $t_0$. All observers agree on this. The flow of time is the progression of the universal state from cause to effect. This is why the flow of time makes sense.

However measurements show the speed of light is constant. This leads to the failure of simultaneity. Robert and Alicia pass each other at relativistic velocity. Both choose coordinate systems that agree they pass at $(x_0,t_0)$. They look at the event Robert sees as $(x_1,t_0)$

Robert says this is having its moment of existence now. Alicia says the same event already happened or hasn't happened yet. This leads to confusion. One event happens at two different times.

The Block Universe is one way around this. If an event exists at two different times, it must not have a momentary existence. It must exist whenever it is time for it to exist in any frame of reference. This preserves the notion that all events in a slice of space-time defined by a time exist at that time. However, it destroys the notion of flowing time. A succession of events do not come into existence and disappear. The whole block of events in all of space-time just statically exists.

Another way is to let go of the notion that simultaneity is absolute. Each object follows a world line where time flows. Each event that object experiences comes into existence at its time and disappears. But there is no universal way of matching up times of separate events. The match up is as motion dependent as matching up the position of separate events.

This does not change what simultaneity is in relativity. The simultaneity of two separate events measured in a particular inertial frame of reference can be inferred. Robert, sitting at $x_0$, can always rely on his clock at $x_0$ to be uniform. He sends out a pulse of light that reflects off an event at $x_1$ and returns. He records the sendoff and return times. The speed of light is constant, so the pulse spends half the time going out and half returning. The reflection is therefore simultaneous with the event Robert experienced at the time halfway between.

The difference between the Block Universe and Flowing Time viewpoints is purely philosophical. They both use the same space-time diagrams, do the same calculations, and arrive at the same answers. One viewpoint regards the space-time diagram as a block of statically existing events. The other regards it as a collection of loosely matched up histories.

Both notions of time are different from the common sense notion. I don't know of any experiment that can distinguish these interpretations of time. Use whichever one makes you the most comfortable.

However, there is one difference. The Block Universe does not include the progression of state from early time to later time. It must be added. There is some question of how to motivate it and explain the direction. The Flow of Time doesn't explain this progression. It is just assumed.

So if you consider how two universes might be different if one has an object that the other does not, it isn't any different if you think bout the block universe or flowing time.

In this case, you are running two different universes. Nothing reconfigures itself.

Likewise you can think about the universe, and what happens if you suddenly add an object.

If you think in terms of the block universe, you must think about the entire history of the universe at once. You see early history without the object. The object appears and consequences spread out at the speed of light. You would see this as events in the light cone after it appears being different from what they would have been if it had not appeared. History outside the light cone would not be rewritten.

mmesser314
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  • Very interesting answer, I update my original question, if you have time I really like some feedback from you. – ozw1z5rd Jun 04 '21 at 08:28