Gravity / GRT and the Big Bang

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Gravity / GRT and the Big Bang

Postby socrat44 on April 6th, 2020, 11:36 am 

Gravity / GRT and the Big Bang
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a) In 1917 Einstein applied his theory of general relativity
in the universe, and suggested a model of a homogenous, static,
spatially curved universe. . . . He then fiercely resisted
the view that the universe was expanding, despite his
contemporaries' suggestions that this was the case.

b). . . . in 1927, Georges Lemaître,
. . . concluded that the universe was expanding by combining
general relativity with astronomical observations.
Yet, Einstein still refused to abandon his static universe.

c) However, in an April 1931 . . .Einstein finally adopted
a model of an expanding universe.

d) In 1932 he teamed up with the Dutch theoretical physicist
and astronomer, Willem de Sitter, to propose an eternally
expanding universe which became the cosmological model
generally accepted until the middle of the 1990s.

https://www.sciencedaily.com/release...0217102545.htm

e) Later Lemaître's idea became known as the "Big Bang theory''.
---
Was " Hot Big Bang theory'' created from the GRT or vice versa?
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Re: Gravity / GRT and the Big Bang

Postby BurtJordaan on April 6th, 2020, 12:36 pm 

socrat44 » 06 Apr 2020, 17:36 wrote:Was " Hot Big Bang theory'' created from the GRT or vice versa?

IMO, it was from the Einstein-de Sitter model, calculated back to where the density would approach infinity, or better stated, where density diverged. So in that way, it was indirectly from Einstein's GRT.

As a side-note, the 'hot big bang' (even today) does not include a singularity. It started after the theoretical inflation epoch, when the density was surely finite. I don't think Einstein ever accepted a density-singularity at "time=0" or inside black holes, for that matter. He thought that the laws of physics would prevent such an absurdity - and maybe he was right (like he mostly was).
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Re: Gravity / GRT and the Big Bang

Postby socrat44 on April 6th, 2020, 2:20 pm 

What came first, the GRT or the Big Bang?
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Re: Gravity / GRT and the Big Bang

Postby socrat44 on April 8th, 2020, 4:48 am 

socrat44 » April 6th, 2020, 2:20 pm wrote:What came first, the GRT or the Big Bang?
===

According to modern scientific view “The Big Bang”
would not occur in the absence of gravity forces.
===
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Re: Gravity / GRT and the Big Bang

Postby BurtJordaan on April 8th, 2020, 10:22 am 

You have a reference for this "modern scientific view", because I don't agree with it...
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Re: Gravity / GRT and the Big Bang

Postby socrat44 on April 8th, 2020, 11:45 am 

BurtJordaan » April 8th, 2020, 10:22 am wrote:You have a reference for this "modern scientific view", because I don't agree with it...


1 - Gravity is the force that attracts two bodies toward each other.
On a small distances gravity forces are much weaker than EM forces,
but on huge cosmic distances - gravity forces are very strong
2 - EM forces don't work on a huge cosmic distances
3 - God doesn't exist
(modern scientific view)
===
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Re: Gravity / GRT and the Big Bang

Postby socrat44 on April 8th, 2020, 11:46 am 

Gravity is a fundamental force in nature.
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Re: Gravity / GRT and the Big Bang

Postby BurtJordaan on April 8th, 2020, 12:54 pm 

We have no workable theory of quantum gravity, never mind one that operated before the BB!
GRT is only applicable way this side of the BB and quantum theories have no gravity.

So again, where is the scientific reference?
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Re: Gravity / GRT and the Big Bang

Postby davidm on April 8th, 2020, 5:50 pm 

socrat44 » April 8th, 2020, 9:46 am wrote:Gravity is a fundamental force in nature.
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Re: Gravity / GRT and the Big Bang

Postby davidm on April 8th, 2020, 5:50 pm 

socrat44 » April 8th, 2020, 9:46 am wrote:Gravity is a fundamental force in nature.


Gravity is not a force, so there is that ...
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Re: Gravity / GRT and the Big Bang

Postby curiosity on April 11th, 2020, 4:27 pm 

Gravity is not a force, so there is that ...


Correct !!! Gravity is an effect on the fabric of space-time. Have you ever wondered why there is currently no explanation for a mechanism capable of causing this effect?
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Re: Gravity / GRT and the Big Bang

Postby socrat44 on April 14th, 2020, 11:18 am 

curiosity » April 11th, 2020, 4:27 pm wrote:
Gravity is not a force, so there is that ...


Correct !!! Gravity is an effect on the fabric of space-time.
Have you ever wondered why there is currently no explanation
for a mechanism capable of causing this effect?


How many dimensions does ''the fabric of space-time'' have?
How many dimensions does ''the Gravity'' have?
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Re: Gravity / GRT and the Big Bang

Postby curiosity on April 14th, 2020, 8:19 pm 

There are two components of space-time, but they are bound together in a continuum, so in reality they are a single phenomenon, The strange thing about space-time is that neither space nor time is actually a constant. Spatial distances can be stretched or compressed and the same goes for temporal separations, it is this that allows space-time geometry to exist. The best way to think of space-time geometry is to compare it to a map with elevation contours, but with space-time the contours are in three dimensions and the contours show how stretched or compressed locations in space-time are. The speed of light is responsible for binding space and time together and it is the common denominator which allows a distance to be given as a timing and vice-versa. No matter how stretched or compressed any path through space-time may be that stretching or compression is proportionate in both space and time, due to the speed of light, So.. the only way we can detect disturbances in space-time geometry is by its effect on matter which will Gravitate toward locations where the space-time is most compressed ( that's why its called gravity!)

Apologies for this rather rushed reply... I'm hoping I will have more time tomorrow, as I haven't yet made the point I wanted to make.

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Re: Gravity / GRT and the Big Bang

Postby BurtJordaan on April 15th, 2020, 2:46 am 

curiosity » 15 Apr 2020, 02:19 wrote:No matter how stretched or compressed any path through space-time may be that stretching or compression is proportionate in both space and time, due to the speed of light, So.. the only way we can detect disturbances in space-time geometry is by its effect on matter which will Gravitate toward locations where the space-time is most compressed ( that's why its called gravity!)

This is roughly true, but it is not the only way. In fact using light itself is a superior tool for detecting the warping of spacetime. The amount of bending and the time delay of a ray of light reflected from nearby objects and gravitational lensing from distant objects provide us with a more refined measurement.
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Re: Gravity / GRT and the Big Bang

Postby curiosity on April 15th, 2020, 9:19 am 

[quoteThis is roughly true, but it is not the only way. In fact using light itself is a superior tool for detecting the warping of spacetime. The amount of bending and the time delay of a ray of light reflected from nearby objects and gravitational lensing from distant objects provide us with a more refined measurement.][/quote]

That's what I get for rushing my response .... Yes of course the warping of space-time can be detected by its effect on the passage of photons and I know my analogy was rather imprecise, but I get so used to peoples eyes glazing over if I mention space-time curvature, gravitational gradients, time dilation or length contraction, that I avoid such terms if I possibly can.

I do really appreciate constructive criticism though. So.. Well done for staying alert and picking up on my unintentional omission.
Unfortunately I'm rather busy at the moment, but I'm hoping I will be able to find time this evening for further. participation
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Re: Gravity / GRT and the Big Bang

Postby bangstrom on April 15th, 2020, 9:22 pm 

curiosity » April 15th, 2020, 8:19 am wrote: I get so used to peoples eyes glazing over if I mention space-time curvature, gravitational gradients, time dilation or length contraction, that I avoid such terms if I possibly can.


This is a common response to space-time explanations of gravity so I also prefer to avoid such terms. It is difficult to visualize how either space or time can curve so I prefer to think of gravity as areas of shorter space and slower time. That image appears less abstract than space-time curvature.
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Re: Gravity / GRT and the Big Bang

Postby socrat44 on May 1st, 2020, 2:47 pm 

bangstrom » April 15th, 2020, 9:22 pm wrote: I prefer to think of gravity as areas of shorter space and slower time.
That image appears less abstract than space-time curvature.


Gravity is areas of shorter (local) gravity-space and
slower (local) gravity- time.
Around local gravity masses (stars) the flat 2-D ''space-time''
is curveted. The gravity-masses in the universe is about 5%.
Therefore the universe as whole is flat 2-D ''space-time'' and
gravity is local 3 -D effect of masses and energy.
===
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Re: Gravity / GRT and the Big Bang

Postby bangstrom on May 1st, 2020, 3:24 pm 

I would raise that explanation by one dimension and say gravity is our 3D spacetime being curved into 4D.

I can’t believe our visible gravity-masses are 6% of the total but that is what we are told.
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