# Hijack from Universal Concept of Time (Is the Big Bang wrong?)

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2 hours ago, lucien216 said:

Thanks. I am trying to wrap by brain around this in practical terms,(...,...,...)......  to compare it to.

There are 2 points here:

1. If Relativity is used to describe the BB, how does it come that the result of the BBT is an  absolute number (~13BY ago) and not a relative number (~13BY before us). The difference is subtle. The 2nd concept means that any observer, wherever he is, whenever he lives, will measure the time to the BB as~13 BY. It is NOT what is supposed to be. It is supposed that an ancient observer would have measured say 11BY, and another in the future will measured  say 20 BY ago. Both of them using the same theory (Relativity) but applied to different measurements (because the Universe is changing over time). The 2nd concept above could only be feasible if the Universe was not changing over time.

2. If you look in your telescope and you observe an alien on another planet, this alien will be delayed, you will see him as it was a few minutes ago. The alien, from his point of view, will also see you a few minutes ago, the same delay goes for both sides. Now the question is: Is there currently an alien living in the future, looking at us? And we will receive his message in few minutes? Or are we all on the surface of the same "time-sphere", in an universal "now" situated ~13 BY from the BB? (I hope the question is clear)

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3 hours ago, lucien216 said:

So now the concept of 'TIME' becomes something based on you. Time is not 'external'. Time is what you experience and can only be different when compared to someone else. That's logical right?

Correct. That is why it is called the theory of "relativity" - it is about measurements made by one observer and compared to the measurements made by another. This applies to time, length, energy and maybe other things. You can only tell that these are different if you compare them. But we also know how to calculate what someone else will measure.

6 minutes ago, michel123456 said:

1. If Relativity is used to describe the BB, how does it come that the result of the BBT is an  absolute number (~13BY ago) and not a relative number (~13BY before us).

Those are the same thing. It is not an absolute number.

It is 13.8 billion years ago / before now as measured by us. It could be a different number measured by someone else at a different place (or at a different time, obviously).

8 minutes ago, michel123456 said:

The 2nd concept means that any observer, wherever he is, whenever he lives, will measure the time to the BB as~13 BY.

That makes no sense. We have a calendar based on the (supposed) birth of Christ. So, currently, that happened 2020 years ago. Next year it will have happened 2021 years ago.

Similarly, this year the big bang happened 13.8 billion years ago. Next year it will have happened 13.8 billion + 1 years ago.

That is a bit silly because the numbers are not exact enough that one year will make any difference, so it would be better to say:

This year the big bang happened 13.8 billion years ago. In 1 billion years time, it will have happened 14.8 billion ago.

11 minutes ago, michel123456 said:

It is supposed that an ancient observer would have measured say 11BY, and another in the future will measured  say 20 BY ago.

If they had measured it 2.8 billion years ago and 6.2 billion years in the future, yes.

12 minutes ago, michel123456 said:

2. If you look in your telescope and you observe an alien on another planet, this alien will be delayed, you will see him as it was a few minutes ago. The alien, from his point of view, will also see you a few minutes ago, the same delay goes for both sides. Now the question is: Is there currently an alien living in the future, looking at us? And we will receive his message in few minutes? Or are we all on the surface of the same "time-sphere", in an universal "now" situated ~13 BY from the BB? (I hope the question is clear)

I'm not sure what the question is. We can't know if there is an alien looking at us. How can there be "currently an alien living in the future"? It is either current or in the future (or in the past).

Take a real example: Betelgeuse may have already gone supernova. We won't know until the light reaches us. When it does, we will (informally) say "Betelgeuse has just gone supernova". But obviously it will have happened about 640 years before that.

But none of that has anything to do with relativity or the age of the universe.

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If you can accept the fact that 'now' is observer dependent, and each observer( next to you, or on other planets ) has their own "now' because of the finite speed of light and causality considerations, then it becomes easy to explain.

If you are looking at a galaxy 1 Billion LY away, you see it 1 Billion years in the past.
If you had a telescope that would allow you to see the aliens measurements/calculations, you would see them estimate the universe to be 12.7 billion years old.
If you could do the same at 5 Billion LY distance you would see another group of aliens estimating an age of 8.7 Billion years.

This is, of course, disregarding strong gravitational influence.

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On 1/30/2020 at 5:19 PM, MigL said:

If you can accept the fact that 'now' is observer dependent, and each observer( next to you, or on other planets ) has their own "now' because of the finite speed of light and causality considerations, then it becomes easy to explain.

If you are looking at a galaxy 1 Billion LY away, you see it 1 Billion years in the past.
If you had a telescope that would allow you to see the aliens measurements/calculations, you would see them estimate the universe to be 12.7 billion years old.
If you could do the same at 5 Billion LY distance you would see another group of aliens estimating an age of 8.7 Billion years.

This is, of course, disregarding strong gravitational influence.

To, 1st of February 2020, where are those galaxies? Do they already exist in year 3000? (if the question is not too bogus).

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1 hour ago, michel123456 said:

(if the question is not too bogus).

!

Moderator Note

One problem with your questions is they are not directed at the OP, and not on topic. Please stop hijacking threads to discuss your particular issues in understanding time.

Split

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3 hours ago, michel123456 said:

To, 1st of February 2020, where are those galaxies? Do they already exist in year 3000? (if the question is not too bogus).

Of course they will still exist in the year 3000. The lifetimes of galaxies are measured in many billions of years. They are not going to disappear in less than 1,000 years.

I think that galaxies we see as being 1 billion light years away will be roughly 1.1 billion light years now.

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You keep throwing 'future' into the mix.
I don't see where that comes from, as there is no mechanism for looking into the future.

Anytime you look into distance, you are looking into the past, because light takes one second to travel 186000 miles.
If you look out your window at your neighbour cutting the lawn, you are 'seeing' him nanoseconds in the past.
But the opposite is NOT true !
When he looks at you and waves, he is NOT looking into the future back at you; he is also looking nanoseconds into the past.

His past.
Which is different from yours.

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To put succinctly every signal every observer receives is in the past regardless of distance to the emitter.

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On 1/29/2020 at 7:08 PM, michel123456 said:

There are 2 points here:

1. If Relativity is used to describe the BB, how does it come that the result of the BBT is an  absolute number (~13BY ago) and not a relative number (~13BY before us). The difference is subtle. The 2nd concept means that any observer, wherever he is, whenever he lives, will measure the time to the BB as~13 BY. It is NOT what is supposed to be. It is supposed that an ancient observer would have measured say 11BY, and another in the future will measured  say 20 BY ago. Both of them using the same theory (Relativity) but applied to different measurements (because the Universe is changing over time). The 2nd concept above could only be feasible if the Universe was not changing over time.

The absolute number is, indeed, the consequence of the universe changing.  So, what you named "2. concept" is nonsense.

Quote

2. If you look in your telescope and you observe an alien on another planet, this alien will be delayed, you will see him as it was a few minutes ago. The alien, from his point of view, will also see you a few minutes ago, the same delay goes for both sides. Now the question is: Is there currently an alien living in the future, looking at us? And we will receive his message in few minutes? Or are we all on the surface of the same "time-sphere", in an universal "now" situated ~13 BY from the BB? (I hope the question is clear)

This is already a metaphysical question.

If you follow the spacetime interpretation, there exists no absolute time, and all the universe (including we ourselves in 20 years) exists.  (Once in such a world there is no "now", one cannot say "exists now", but there would be no difference between what exists "now" and what exists "in 20 years", it is all the same whole history of the whole universe.

But you can also assume that there exists an objective absolute time, which would be, roughly, the time after the BB as measured by an observer in rest relative to the CMB radiation. (But this would be only an approximation.  The interpretation which would provide such an absolute time would have to provide an exact equation for absolute time too. In this case, the alien which exists now may look at us, but will see only our past.)

Edited by Schmelzer
The moderation wants to have it removed.

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On 2/1/2020 at 5:30 PM, michel123456 said:

To, 1st of February 2020, where are those galaxies? Do they already exist in year 3000? (if the question is not too bogus).

very bogus, the light catches you, you cant catch the light. 🙄

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38 minutes ago, Schmelzer said:

In my generalization of the Lorentz ether to gravity, it is harmonic time. In this case, the alien which exists now may look at us, but will see only our past.

!

Moderator Note

Your pet theory has no place in this discussion.

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On 2/12/2020 at 3:43 PM, Schmelzer said:

The absolute number is, indeed, the consequence of the universe changing.  So, what you named "2. concept" is nonsense.

It may look like nonsense, yes. But let's think about it twice. If Relativity is a theory that describes what an observer observes, in fact it describes what any observer would observe anywhere in the universe, because there is no privileged observer, there is no central point. But we also know that any point in space is correlated with its position in time. Following current theories, we are at a special position in time: we are at ~13BY from the beginning. Which means that we are lost in space but not in time. The 4th dimension once again is treated differently from the 3 others. And I wonder why.

I suspect you know this diagram: (from http://www.astro.ucla.edu/~wright/cosmo_03.htm)

Well I suspect that any observer situated at any point of this diagram would plot exactly the same thing. It works like a fractal. If you change position, the graph will restore exactly the same.IOW that from any point of space and time, the BB would appear as ~13BY before.

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5 minutes ago, michel123456 said:

If Relativity is a theory that describes what an observer observes, in fact it describes what any observer would observe anywhere in the universe, because there is no privileged observer, there is no central point. But we also know that any point in space is correlated with its position in time. Following current theories, we are at a special position in time: we are at ~13BY from the beginning. Which means that we are lost in space but not in time. The 4th dimension once again is treated differently from the 3 others. And I wonder why.

The translational symmetry is a symmetry of the laws of Nature, not of the actual configurations.  The laws of GR have such translational symmetry.  We use the same equations for all times. The matter configuration we see around us have some approximate translational symmetry in space only, and only on very large distances.  Nobody knows why, these are simply the facts we observe.

Quote

I suspect you know this diagram: (from http://www.astro.ucla.edu/~wright/cosmo_03.htm)

Well I suspect that any observer situated at any point of this diagram would plot exactly the same thing. It works like a fractal. If you change position, the graph will restore exactly the same.IOW that from any point of space and time, the BB would appear as ~13BY before.

That's wrong.  The FLRW ansatz has translational symmetry in spatial directions only.  There is no translational symmetry in time.  Observers at other times will observe differences.  They will observe, in particular, higher matter densities, a larger temperature of CMBR, less inhomogeneity in space.  And, of course, they will, using the same methods we use, measure a different time after the BB.

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17 minutes ago, michel123456 said:

Following current theories, we are at a special position in time: we are at ~13BY from the beginning.

In what way is that a "special" position in time?

How is it different from being far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy?

You have this bizarre misunderstanding of relativity as if it says that everything must always look the same for everyone everywhere, which is obviously wrong.

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13 hours ago, Schmelzer said:

There is no translational symmetry in time.  Observers at other times will observe differences.  They will observe, in particular, higher matter densities, a larger temperature of CMBR, less inhomogeneity in space.  And, of course, they will, using the same methods we use, measure a different time after the BB.

I am aware that it is the current understanding.

13 hours ago, Strange said:

You have this bizarre misunderstanding of relativity as if it says that everything must always look the same for everyone everywhere, which is obviously wrong.

Yes, this is my understanding. "everything must always look the same for everyone everywhere". Why is it wrong? It baffles me when some scientist say that in some BY from now, the universe will appear su much different from now that the observer will observe only our own galaxy making him believe it is the only one galaxy in the universe (see Krauss statements and the relevant thread ). Evidently (to me) it cannot be that way.

The situation MUST be that all observers roughly observe the same thing. Otherwise we are wrong.

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1 hour ago, michel123456 said:

Yes, this is my understanding. "everything must always look the same for everyone everywhere". Why is it wrong?

Because it is not what the theory of relativity says. It is something you have invented based purely on your misunderstanding of the word "relativity".

What the theory says is that some measurements depend on the frame of reference of the observer; in other words different observers may see the same thing differently. This is almost the exact opposite of your made-up version.

1 hour ago, michel123456 said:

The situation MUST be that all observers roughly observe the same thing. Otherwise we are wrong

No. It is just you that is wrong.

If not, why not show the mathematics, or even a reference, that supports your claim.

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2 hours ago, Strange said:

No. It is just you that is wrong.

Amen.

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Here below a tentative for the explanation of concept 2 "The 2nd concept means that any observer, wherever he is, whenever he lives, will measure the time to the BB as~13 BY"

At left is the original graph. The green arrow on the left is Time to the Big Bang as observed by A.

A-1 in the bottom of the graph is an observer closer to the BB.

At right the orange rectangle is a blow-up of the small region around A-1. The blow-up shows exactly the same kind of graph as the original one.

Standard understanding says that the left observer (A)  reads the green arrow ~13BY (as measured today).  And standard understanding says the right observer (A-1)  reads his green arrow ~3BY (as measured then). That is what you say (please correct me if I am wrong)

BUT if the green arrow is a function of other measurements made by A, it may be that both observers will read their own green arrows as the same. That's what I am trying to say.

Edited by michel123456

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2 hours ago, michel123456 said:

Here below a tentative for the explanation of concept 2 "The 2nd concept means that any observer, wherever he is, whenever he lives, will measure the time to the BB as~13 BY"

At left is the original graph. The green arrow on the left is Time to the Big Bang as observed by A.

A-1 in the bottom of the graph is an observer closer to the BB.

At right the orange rectangle is a blow-up of the small region around A-1. The blow-up shows exactly the same kind of graph as the original one.

Standard understanding says that the left observer (A)  reads the green arrow ~13BY (as measured today).  And standard understanding says the right observer (A-1)  reads his green arrow ~3BY (as measured then). That is what you say (please correct me if I am wrong)BUT if the green arrow is a function of other measurements made by A, it may be that both observers will read their own green arrows as the same. That's what I am trying to say.

everywhere is the centre of the universe

Quote

Yet there is no centre to the expansion; it is the same everywhere.  The Big Bang should not be visualised as an ordinary explosion.  The universe is not expanding out from a centre into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell.

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