David Levy

I wonder why our scientists do whatever it takes to support the BBT.

What is so Unique in the BBT? What makes it different from many other theories?

Why our scientists always try to adapt the BBT to new discoveries, while they do not stop even for just one moment and ask themselves if this theory is incorrect?

 

Just few obstacles of the BBT:

 

1. Size/Quantity - After the inflation (10^-32) the size of the early Universe was about 10 cm (as grapefruit) and it includes particles which could fit info 375 billion trillion galaxies. Is it feasible? How can a natural force create this huge amount of particles in just a fraction of a second?

 

2. Speed - At the end of the inflation process, it is expected that the Universe will expand at lower speed. However, based on the data, at the end of the first second, the size of the universe was 4 LY which means an expansion speed of over 6 Million light speed. Is it feasible?

 

3. Density distribution - Due to the bang and the Ultra high momentum/speed it is expected that all the plasma will move out from the bang - in some sort of ball shell. So as the plasma is moving in all directions, In the middle - it is not expected to find any sort of plasma. Over time - it is expected that this aria should be clear from all mass/plasma. In all the experiments of bangs it was proved that there is no way to get a smooth density distribution. Hence, how could it be that the BBT set a nice density distribution in space (all over the Universe)?

 

4. Expansion reduction - At the age of 500,000 years, the size of the universe was 1,500,000 LY - which means a plasma speed of 1.5 Light speed. However, at the first second the speed was 6 Million the speed of light. Therefore we need to verify how could it be that there is so severe speed reduction - from 6 million to 1.5 light speed (reduction of 4 million times). Due to the momentum in space, it is not expected to see that kind of speed reduction. Please also remember that the inflation had ended long before the end of the first second. So, is it feasible?

 

5. Black body signature - when the age of the Universe was 380,000 years old, the plasma moves faster than the speed of light. At that speed, a photon can't meet the expanding early plasma edge. Therefore, from a photon point of view it is moving in an open space. An open space means no black body signature.

 

6. Why the science is not taking care about the moment before the Bang? What could be the natural process which leads to this magnificent bang? Why our scientists ignore this section?

 

7. Repeatable activities in the Nature - In our universe any natural activity is repeatable. Day, night, rain, snow, supernova… So, why the big bang is not repeatable? Why only one bang?

 

So, how could it be that the whole science community protects it so strongly?

The BBT is at the top, while Einstein is much lower and below.

The science community is using Einstein equation as a mathematical proof for the BBT, but they reject all his messages which contradict the BBT.

 

It seems to me that if you want to consider yourself as a scientist, your first mission is to believe in the BBT.

Actually, if you do not believe in the BBT you won't be considered as a scientist among the science community.

Why?

 

Normally - belief goes with religion.

If you are Christian - you should believe in Jesus.

If you are Islamic - you should believe in Mohammad.

If you are Jew - you should believe in God.

If you are scientist - you should believe in BBT.

 

Does it mean that the BBT is some sort of religion?

 

Somehow, in a fraction of a second – after the Big bang, incredible quantity of practical -which can easily fit to 375,000,000,000,000,000,000,000 (375 Billion trillion) galaxies - had been created.

 

Just think about this Idea, what a huge power is need for that...

Who can set this quantity? How could it be? It seems to me that only a divine power can set this kind of a bang.

 

So, is it the reason why the Pop had adopted the BBT?

In this case, our scientist can focus on the moment after the bang while the moment before is under the Pop control.

 

I hope that Pop will forgive me, but I really can't understand why it is so important for the Christianity to show that divine power is needed for our life generation over generation.

 

Somehow, in the past they didn't accept Darwin Theory, Galileo discoveries and many others.

So does it mean that if you are Christian you should believe in the BBT?

I would like to highlight that I have full appriciation to Christianity, but somehow we must distinguish between science and religion.

O.K.

Let's start with mathematics.

We all know by now, that the discovery of the acceleration expansion have set a severe violation in the BBT mathematics.

It just didn't work on the basic Einstein equation.

I would expect that this violation by itself should send the BBT into deep freeze.

However, our scientists couldn't give up on this unrealistic Theory. (As there was no real alternative at that time -1998).

Therefore, they have decided to call back the forbidden cosmology constant - the one which Einstein himself have stated that it was his biggest mistake.

With this constant, our scientists have set the requested mathematical fit.

Actually, Einstein had added this constant to prove totally different theory - Static universe theory:

https://en.wikipedia.org/wiki/Cosmological_constant

 

"Einstein included the cosmological constant as a term in his field equations for general relativity because he was dissatisfied that otherwise his equations did not allow, apparently, for a static universe: "

I have full thrust in Einstein that by using the cosmology constant he had proved mathematically the Static Universe Theory.

Today, the science community is using that constant to prove the BBT.

So, if with the same constant it was feasible to prove two totally different theories, I would assume that with the help of that constant we can proof any theory which we can dream on.

However, Einstein had stated clearly that the cosmology constant was its biggest mistake.

Therefore, I have full confidence in Einstein. We shouldn't use this constant in order to prove any sort of unrealistic theory!!!

It is clear to me that the only real mathematical solution must be based on basic Einstein equation, without any added constant and without any change in the parameters.

I would never ever use this forbidden cosmology constant to prove my theory. We are cheating ourselves by using that constant. We shouldn't use it to prove the BBT, we shouldn't use it to prove the Static universe and we shouldn't use it at all!

This cosmology constant was the biggest Einstein' mistake. If we take Einstein as an important scientist, we must accept his will as is.

 

Hence, before you ask me to give you a mathematical proof, you are requested to prove the BBT on basic Einstein equation (Without the cosmology constant)!

Unfortunately, currently I have no deep knowledge in advanced science mathematics, but I'm quite sure that with some help I would be able to find a perfect fit between basic Einstein equation and my breakthrough Theory.

Without it – my theory is just useless.

Dear All

 

Thanks for the excellent support which I have got from you.

 

Now I have much better visibility on the BBT.

 

It is clear to me that the science community takes the BBT as the only feasible solution for our Universe.

 

Therefore, a BBT filter applies on any evidence or idea.

 

This is a severe mistake.

 

Our Universe is infinite in its age and in its size.

 

The Big bang is needed to set only the first SMBH in the whole Universe.

 

Once it is there, by using Higgs Boson, Newton gravity and velocity momentum in space, I can explain every phenomenon in our Universe, so simple and clear.

 

There is no need for acceleration expansion, inflation or any other current hypothesis.

 

I'm quite sure that one day students will learn this break through theory in Universities.

 

However, I have no intention to upset anyone at this forum.

 

So I have a simple question -

 

Is it possible to discuss science without the BBT filter (Offline, or some other way)?

 

1927

 

 

Thanks

 

 

We just need to make the equation fit the observations.

 

I'm not sure that we can call the accelerating expansion as observation.

I have tried to understand the real meaning of the accelerating expansion of the universe:

https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_universe

 

The expansion of the universe has been accelerating since the universe entered its dark-energy-dominated era, at redshift z ≈ 0.4(roughly 5 billion years ago)

 

The first evidence for acceleration came from the observation of Type Ia supernovae, which are exploding white dwarfs that have exceeded their stability limit.

For supernovae at redshift less than around 0.1, or light travel time less than 10 percent of the age of the universe, this gives a nearly linear distance–redshift relation due to Hubble's law. At larger distances, since the expansion rate of the universe has changed over time, the distance-redshift relation deviates from linearity, and this deviation depends on how the expansion rate has changed over time. The full calculation requires integration of the Friedmann equation, but a simple derivation can be given as follows: the redshift z directly gives the cosmic scale factor at the time the supernova exploded.

So a supernova with a measured redshift z = 0.5 implies the universe was 1/1 + 0.5 = 2/3 of its present size when the supernova exploded. In an accelerating universe, the universe was expanding more slowly in the past than it is today, which means it took a longer time to expand from two thirds its present size to its present size compared to a non-accelerating universe."

Hence, our simple pure observation is – Redshift.

 

We do not observe directly the accelerating expansion value.

 

However, based on the BBT theory, that value of observed redshift represents accelerating expansion of the universe.

 

That is quite clear as the BBT theory represents a young age Universe - only 13.8 BY. Therefore, in order to accomplish that kind of redshift in that limited time frame – an accelerating expansion is needed.

 

I would assume that if for example the age of the Universe would be considered as Infinity the outcome of the same redshift observation might be totally different.

 

In other words:

 

We do not measure directly the accelerating expansion value. We only measure the Redshift. The accelerating expansion is a direct outcome of the BBT theory impact on our observation. If we have used different Theory, we could get different outcome from the same observation.

 

Therefore – It is a severe mistake that we call the accelerating expansion as observation.

 

IT IS NOT AN OBSERVATION. It is a simple outcome of how we see the redshift observation through the BBT eyes.

 

If we call the accelerating expansion – Observation, we mislead ourself.

 

Its time to set a clear distinguish between what we see and what we think as an outcome of our observation.

 

There could be a significant gap between the two.

 

 

 

B and C are the same thing.

 

 

There is also a gap between Theory and equation.

 

BBT is theory. Steady state is Theory. Once upon a time our theory was that the Earth is the center of the Universe. So what? Every era might come with deferent theory.

 

Those theories aren't written on a stone. There are valid as long as we didn't find better replacement. Theories could be valid for a limited time frame.

However, equations and laws are much more solid than any temporary theories.

1+1 = 2 equation is solid. Newton law is solid. I do believe that the basic Einstein equation is much more solid than any sort of theory (including the BBT).

 

Huh? That makes no sense.

That is what I said: the constant was added so that the results of the equation (i.e. the predictions of the big bang theory) match the observations.

 

 

 

As I have stated; we shouldn't change our equations for any sort of temporary theory including the BBT.

 

In the past we killed the state theory as it didn't expected the expansion.

 

Now we should reconsider the BBT theory as it didn't expected to find accelerating expansion of the universe.

 

Thanks Strange

 

Do appreciate your explanation.

 

What do you mean "proved his equation"?

Do you mean did he compare the predictions of the theory against observation?

If so, then the answer is yes. And when those observations showed that the universe was actually expanding, the cosmological constant was set to zero.

Now we have seen that the expansion is accelerating, the value has been adjusted again.

THIS IS HOW SCIENCE WORKS.

 

So, the accelerating expansion was a critical discovery of our Universe.

Based on this discovery we have decided to change Einstein equation by adding the cosmology constant.

Let's start by looking at the history:

Based on the first expansion discovery (somewhere at 1950?), our scientists had developed the BBT theory (let's call it old BBT as it wasn't expected to see any sort of accelerating expansion in our Universe).

Till the accelerating expansion discovery in 1998, the old BBT was a perfect fit between our observations and the basic Einstein equation (without the cosmology constant)

 

However, this accelerating expansion set a violation between the old BBT and the basic Einstein Equation.

 

So, our scientists had to find a solution.

 

They could say – "Huston, we have a problem".

They could say – We have a problem with the old BBT theory. As we didn't expect to see that phenomenon we must look for better Theory which can give a clear explanation for what we see.

 

So, how could they solve the problem?

 

First we have to understand the key elements for any problem/solution:

 

A. Observation – Represents the discoveries and evidences. We can't change it.

B. Equation/law – represents the knowledge in mathematics Physics which had been developed by key scientists during the centuries. (I had the impression that we also shouldn't change it in order to meet any sort of theory). Actually, long time ago, Einstein by himself had decided to add the cosmological constant to his relativity equation in order to protect some sort of theory which he believed in. But later on, he was brave enough to say that it was his biggest mistake.

C. Theory – this must be flexible. It must be the bridge between the observations to the equation.

 

Hence

 

I would expect that the science community will set the old BBT on the table and try to verify different theories in order to find the perfect match between the new observation/discovery and the basic equations.

 

However, that was not the case. As instead of open the mind for alternative Theory, we have opened our mind for alternative equation.

 

No.No. No. No. NO.

The constant was added so that the equation matches what we observe. That's it.

 

Sorry - It seems to me that the Constant was added so the equation matches between the BBT and the observation.

So, we did exactly the same mistake as Einstein.

It was so important for us to protect the BBT that we have agreed to call back that cosmological constant (which Einstein said that it was his biggest mistake) in order to close the gap between the observation and the old BBT theory.

Hence, a new section of acceleration expansion had been added to the old BBT – and now we can rest with this new updated BBT till the next discovery.

Did I miss something?

Is this how science works?

It is stated:

https://en.wikipedia.org/wiki/Static_universe

"Albert Einstein added a positive cosmological constant to his equations of general relativity to counteract the attractive effects of gravity on ordinary matter, which would otherwise cause a spatially finite universe to either collapse or expand forever."

 

But then he understood that it is a severe mistake and therefore, he had eliminated that cosmological constant from his equation.

I wonder if Einstein had proved his equation – with or without the cosmological constant.

If Einstein had confirmed its equation without the cosmological constant – then it is forbidden to add it back. We shouldn't do it under any circumstances.

If he didn't, then yes- we have full authority to update the equation as we like. Actually without a solid proof by Einstein – the sky is the limit.

We can add that cosmological constant or even make significant change in that equation.

Therefore, if Einstein didn't confirm his equation (without the cosmological constant), then I fully agree with your explanation:

People are human, the fact one of them once got something wrong shouldn't be terribly surprising and why science doesn't care who said what only how good the models are (how well they compare to measurements).

 

 

So, yes, I fully agree that even Einstein can make a mistake.

However, if he had a severe mistake in his equation, then could it be that other scientists might have a mistake? Could it be that there is an error also in the updated equation (with this constant)?

The main question is as follow:

By adding that constant we have confirmed the BBT, however –by confirming the BBT does it mean that it is a solid proof for the existence of the cosmological constant in the equation?

How can we prove the updated equation?

Therefore, without a real approval, there is always a possibility that the updated equation (with the cosmological constant) isn't valid by 100%.

 

In other words – we can change the equation, we can add the cosmology constant to get the fit of the BBT, but in this case we must find a way to confirm the updated equation.

 

On the other hand, if we think that Einstein made a severe mistake in his decision to eliminate the cosmology constant, if we decide to add it against his clear will, then why do we still call it Einstein equation?

How could it be that after setting a severe change in this equation we still call it under his name?

 

If someone came along with a mathematical theory as robust as our current theory but more accurately agreed with the observations (taking error analysis into account) then we would start using the new theory.

 

What you have to bear in mind is that BBT and general relativity are incredibly accurate in the domains of applicability. So a simple first test as to whether a new theory is valid is whether it gives the same numerical predictions as them.

 

Interestingly this can be done for general relativity. Where Newtonian gravity works GR must produce the same result else we'd have known quickly that it was not going to work.

 

How robust is our current mathematical theory?

 

1. Is it based on Einstein general relativity equation?

 

2. Do we use the forbidden cosmology constant in order to prove the theory?

 

If the answer to the above is positive, then the answer had already been given by Einstein.

 

He had already said that this is a big mistake.

 

However, if we can prove our current mathematical theory by using Einstein general relativity equation, without the cosmology constant -

 

Then we can claim clearly that we have a robust mathematical theory.

 

As it matches the evidence he would do the same.

Because it matches what we observe (the same reason it was set to zero previously).

 

O.K.

Let's see if I understand it correctly:

We have developed the BBT theory based on our observation.

 

This theory includes several sections including the expansion, inflation and others.

In order to support those theories and hypothesis we had to go back to Einstein equation and add that forbidden Cosmological constant.

In other words, we need the cosmological constant to support our updated theories about the Universe.

 

Now, if someone will dare to come and say that there is a simple explanation for what we see, we will tell him that our theories had been proved by Einstein equation.

As no one can argue with Einstein - then no one can argue with our current theories.

Win win solution

Did I understand it correctly?

Sorry, It seems that I didn't explain myself correctly.

 

 

No equation is set in stone.
Theories and models are adaptive hence the sheer power of mathematics. We still call it the Einstein field equations as he is acreddited with the original work.
This does not mean we throw out the entire work simply because we had to adapt it or ignore the contributions of the original.

 

I fully agree with you that theories and models are adaptive.

We can change and update the equation.

 

 

Still doesn't change the detail Einstein was probably more than aware the cosmological constant was problematic.
Personally I feel that he would be truly proud that his contributions to those links and is of fundamental importance in all of them. Even to this day despite the cosmological constant his works are of immense importance.
He probably would never would have expected his works to so robust. (personal opinion)

Precisely

 

 

Einstein is considered as the father of the modern science.

If we get a command from a father then we must respect it.

 

Einstein told us clearly that we shouldn't use the cosmological constant in his equation. Therefore, we shouldn't use it.

If we use it, it isn't adaptation. It is violation.

 

However, if we think that we must add a constant to the equation, then at least we shouldn't call it cosmological constant.

We should find new name for this constant and prove our new adaptive equation.

We will give it a new name as it is no longer belonging to Einstein.

If needed, we will also give a Nobel Prize for the scientist which is able to prove the validity of the equation with new name for the cosmological constant.

 

Never the less, it is forbidden to take Einstein equation as is, add the cosmologic constant (which Einstein told us not to use) and then say - yes, this is Einstein equation.

 

I still believe that it is a sever violation of Einstein will.

 

In any case

Why is this cosmological constant so important for us?

Why does it matter what he would think?

 

Well, please see the following and decide by yourself:

 

https://en.wikipedia.org/wiki/Albert_Einstein

 

Albert Einstein was a German-born theoretical physicist. He developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).^[1][5]:274 Einstein's work is also known for its influence on the philosophy of science.^[6][7] Einstein is best known in popular culture for his mass–energy equivalence formula E = mc² (which has been dubbed "the world's most famous equation").^[8] He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect",^[9] a pivotal step in the evolution of quantum theory.

 

Einstein thought that Newtonian mechanics was no longer enough to reconcile the laws of classical mechanics with the laws of the electromagnetic field. This led him to develop his special theory of relativity

 

Known for Influenced Notable awards

Sorry - If I was too direct.

 

But, I have asked myself:

How Einstein would feel or tell us if he could come back to life and see that we are using the cosmological constant against his clear will.

Why would you think that? No physicist is ever the final authority. No equation is set in stone.

 

Theories and models are adaptive hence the sheer power of mathematics. We still call it the Einstein field equations as he is acreddited with the original work.

 

This does not mean we throw out the entire work simply because we had to adapt it or ignore the contributions of the original.

 

 

We must respect and accept Einstein will.

As Einstein said - no, than it is no. There is no room for - but...

He had clearly enounced that the cosmological constant is his biggest mistake and therefore we had been forced to eliminate this constant from his equation

Hence, it is forbidden to add it back against his clearly request and under any circumstances.

Once we add it back - this is a severe violation of his request and his equation.

 

With that cosmological constant - we can't call it Einstein equation any more. It is forbidden!!!

We are using the Glory of the name "Einstein" for an updated equation which is absolutely unacceptable by Einstein himself.

Sorry - but this is a severe violation that the modern science is doing under big "Einstein" name.

If I understand it correctly, we are using this constant in order to prove the expansion.

If that is correct, then we have to find different equation or some other way to prove the expansion!

We shouldn't use Einstein equation against his clear request and will.

 

Yes the first part is correct. The cosmological constant did drop from the equations for a time. However when we discovered the acceleration due to aka dark energy the cosmological constant was reintroduced however its purpose is not identical. Ie its now used to account for the added expansion rate.

 

Side note some older textbooks have the FLRW metric without Lamnda those equations were later fixed in newer textbooks.

 

(This happens to be one example where equations have been upgraded from its origin )

 

If Einstein had eliminated the cosmological constant from his equation then it must be final.

Hence, the cosmological constant must be out of Einstein equation for ever.

 

Could it be that by adding someting to this equation (even if we call it also "cosmological constant"), then it is a sever violation of Einstein equation?

O.K.

 

Einstein originally used the cosmological constant to make the universe static.

However, when he had understood that the Universe isn't static (as he had considered), he claimed that it was a big mistake to add the cosmological constant to his equations of general relativity

 

If that is correct:

 

1. Why he didn't eliminate the cosmological constant from his equation? (If it is a mistake - than please fix it. It was his equation. I would assume that Einstein had to eliminate errors from his equation)

2. Why he didn't say that his theory for universe static was a severe mistake. Why he only focus on cosmological constant?

Thanks

 

Einstein originally used the cosmological constant to make the universe static. His original model without it predicted a contracting or expanding universe.

 

That is clear.

 

 

He originally didn't like that so attempted to make his equations lead to a static solution.

That was his blunder.

 

What do you mean by static solution?

Is it the expansion theory?

I would like to understand the history of the cosmological constant.

 

In the following article it is state:

 

"Albert Einstein added a positive cosmological constant to his equations of general relativity to counteract the attractive effects of gravity on ordinary matter, which would otherwise cause a spatially finite universe to either collapse or expand forever".

 

However, it is also stated:

https://en.wikipedia.org/wiki/Cosmological_constant

 

"Einstein later reputedly referred to his failure to accept the validation of his equations—when they had predicted the expansion of the universe in theory, before it was demonstrated in observation of the cosmological red shift—as the "biggest blunder" of his life.

 

Questions:

1. Why Einstein had considered the cosmological constant as the biggest mistake of his life?

2. Why he didn't eliminate the cosmological constant from his equations of general relativity after understanding his big mistake?

.

 

OK. Looking at it again, your numbers are approximately correct. (This could be a first. We should have some sort of celebration.) I apologise for assuming that every calculation you post would be wrong, based on past experience.

 

The recessional speed is 71 km/s/Mpc and so at 2571 Mph it is 182,500 km/s or 06.c. At double that distance, it is 1.2c.

 

 

Thanks

 

I do appreciate the excellent support which I have got from all of you.

 

We all share the ambition to get better understanding about our complex universe.

 

Because, if there is expansion of space and the galaxies are far enough away that this is significant, then you cannot compare their velocities without using GR to take the expansion into account. Therefore you cannot add velocities as you are doing.

 

Let's look again on that example:

 

B is located at a distance of 2571 Mpc from A and therefore, it is receding at a speed of 0.6c (from A).

C is located at a distance of 2571 Mpc from B and therefore, it is receding at a speed of 0.6c (from B).

 

Hence, the distance between A To C is 5142 Mpc.

The outcome is that the relative speed between A to C is 1.2c

 

What is wrong with that?

This doesn't really make any sense.

 

Why?

Sorry

 

This isn't the main issue.

We discuss on linearly speed at GR.

 

Therefore, the following example of rockets over rockets should work O.K.

 

At t=1 we get:

A-B-C-D-E-F-G-H-I-J-K-L-M

At t=3 we get:

A---B---C---D---E---F---G---H---I---J---K---L---M

I assume that by now we all agree that the following formula isn't relevant for GR

 

[math]\frac{0.6c+0.6c}{1+ \frac{0.6c(0.6c)}{c^2}} = 0.88235... c[/math]

 

Due to the expansion, at that range (2571 Mpc) the speed should be linearly.

Therefore, the relative speed between A and C is 1.2 c.

Well, it seems that I was not clear with my message as I look on Mpc.

 

Therefore, I would like to summarize our discussion as follow:

 

GR works at homogeneous and isotropic global metric, which is estimated for above 100 Mpc.

SR works below 100 Mpc (also estimated).

Expansion has a linear speed and works for GR, while Lorentz Transforms has a non linear speed and works for SR.

 

Hence:

Linear speed based on expansion works for GR at above 100 Mpc.

Non Linear speed based on Lorentz Transforms works for SR at below 100 Mpc.

 

A galaxy which is moving at a speed of 0.6 c, should be located above 100 Mpc.

Therefore, we shouldn't operate Lorentz transforms formula on a galaxy which is located at above 100 Mpc.

 

Just a brief calculation:

 

[latex]70 km/sec/Mpc*4286[/latex] Mpc is 300,020 km/sec.

 

0.6 c = 0.6 * 300,000 = 180,000 km/sec

 

180,000 / 70 = 2571 Mpc

 

Therefore, in order to gain a speed of 0.6 c a galaxy should be located at a distance of 2571 Mpc from us.

That is far above the estimated 100 Mpc for SR.

Don't get your heart set in stone on a set distance. The key is when you have sufficient difference in potential to cause action.

 

I just want to get a brief estimation for: Up to what distance Lorentz Transforms is applicable?

In essence yes though GR is more applicable as you will have numerous variations within that region. Its simply more accurate to map multiple variations via GR than in GR in this instance.

 

Thanks

 

 

Because Lorentz Transforms are part of SPECIAL relativity that only applies locally in flat space.

The expansion of space is described by GENERAL relativity.

 

So can we claim that Lorentz Transforms works up to 100 Mpc? (Which means velocities don't add linearly)

 

While above 100 Mpc we need to use GR:

 

 

Every individual Mpc expands at the same rate 70 km/sec/Mpc. that is the expansion rate at every point in space. It is only when you add up a large number of individual Mpcs that you accumulate to greater than c recessive velocity.

 

(Which means velocities add linearly)

Thanks for the answer.

With regards to - homogeneous and isotropic global metric.

https://physics.stackexchange.com/questions/24881/what-is-meant-when-it-is-said-that-the-universe-is-homogeneous-and-isotropic

 

"A sufficiently large scale (greater than about 100 Mpc), the universe can be treated as homogeneous and isotropic then a uniform density."

 

So, just as a brief estimation - can we assume that up to 100 Mpc it is considered SR, and above that it is GR?