Bbt - Big Bang Theory

[davdan]

In the following article it is stated:

 

https://ned.ipac.caltech.edu/level5/Sept02/Kinney/Kinney3.html

 

1. T ~ 10¹⁵ K, t ~ 10^-12 sec: Primordial soup of fundamental particles.

2. T ~ 10¹³ K, t ~ 10^-6 sec: Protons and neutrons form.

3. T ~ 10¹⁰ K, t ~ 3 min: Nucleosynthesis: nuclei form.

4. T ~ 3000 K, t ~ 300, 000 years: Atoms form.

5. T ~ 10 K, t ~ 10⁹ years: Galaxies form.

6. T ~ 3 K, t ~ 10¹⁰ years: Today.

 

A. How did we estimate the ratio between the temp and time?

B. What was the size of the universe at those phases of time?

Edited June 4, 2017 by davdan

[exchemist]

In the following article it is stated:

 

https://ned.ipac.caltech.edu/level5/Sept02/Kinney/Kinney3.html

 

1. T ~ 10¹⁵ K, t ~ 10^-12 sec: Primordial soup of fundamental particles.

2. T ~ 10¹³ K, t ~ 10^-6 sec: Protons and neutrons form.

3. T ~ 10¹⁰ K, t ~ 3 min: Nucleosynthesis: nuclei form.

4. T ~ 3000 K, t ~ 300, 000 years: Atoms form.

5. T ~ 10 K, t ~ 10⁹ years: Galaxies form.

6. T ~ 3 K, t ~ 10¹⁰ years: Today.

 

A. How did we estimate the ratio between the temp and time?

B. What was the size of the universe at those phases of time?

I have no idea about your A

 

About your B, I have the impression that the question is only answerable if you refer to the size of observable universe, rather than the whole universe. See for example here: https://physics.stackexchange.com/questions/32917/size-of-universe-after-inflation

[davdan]

I have no idea about your A

 

About your B, I have the impression that the question is only answerable if you refer to the size of observable universe, rather than the whole universe. See for example here: https://physics.stackexchange.com/questions/32917/size-of-universe-after-inflation

 

Thanks.

 

Well, I fully accept all the starting points of the BBT.

However, after setting the starting points, now they have to prove that the process is feasible.

 

For example:

In the article it is stated:

 

"Consider, for example, a cosmic microwave background (CMB) photon that was emitted as visible light about 379,000 years after the big bang and is just now hitting our microwave detectors (the redshift is z=1089):"

 

So, in order to evaluate this information we need to know the following:

What was the size of the universe when it was at age of 379,000 years?

I would assume that it should be quite compact. 

If we know the expansion speed of the particles + the expansion of the space, we could calculate the estimated size.

Any idea?

[Turtle]

So, in order to evaluate this information we need to know the following:

What was the size of the universe when it was at age of 379,000 years?

I would assume that it should be quite compact.

If we know the expansion speed of the particles + the expansion of the space, we could calculate the estimated size.

Any idea?

Dude; please -again- stop with the color/font/size formatting. The code clutters your post when I have to toggle the edit box to reply. What's more it adds nothing to the reply and wastes your [presumably valuable] time.

 

Here's the information you are looking for. Google is your friend. :rolleyes:

 

The Universe

300,000 yrs.: 3500º Kelvin: [No size given]: Transparent universe - atoms form - matter predominant

500,000 yrs.: 3000º Kelvin: 1,500,000 Light Years (Radius): Photon decoupling

Edited June 4, 2017 by Turtle

[davdan]

Here's the information you are looking for. Google is your friend. :rolleyes:

 

The Universe

 

 

Thanks

 

Great article!

 

The issue is quite clear.

However, as I have stated:

 

"I fully accept all the starting points of the BBT.

However, after setting the starting points, now they have to prove that the process is feasible".

 

So, our scientists have stated that just after the inflation the universe was at the size of grapefruit and it includes particles which could fit to about 357,000,000,000 trillion galaxies.

 

In the following article:

http://www.kheper.net/cosmos/universe/universe.htm

it is stated that after one sec the size of the universe was 4 Light years (radius - 2 light years):

 

1 second

1x10¹⁰

4 light-years

 

 

So, if after one year the radius of the Universe was 2 Light year, then we could assume that the velocity is double than the speed of light.

 

But here – after just one second…

 

1 year = 31 556 926 seconds

Hence, the velocity of the plasma is:

 

V = 31 556 926 * 2 =  6,311,384 Light speed.

 

Is it real?

We know that nothing can move higher than a speed of light.

So, How could it be? 

Edited June 5, 2017 by davdan

[exchemist]

Thanks

 

Great article!

 

The issue is quite clear.

However, as I have stated:

 

"I fully accept all the starting points of the BBT.

However, after setting the starting points, now they have to prove that the process is feasible".

 

So, our scientists have stated that just after the inflation the universe was at the size of grapefruit and it includes particles which could fit to about 357,000,000,000 trillion galaxies.

 

In the following article:

http://www.kheper.net/cosmos/universe/universe.htm

it is stated that after one sec the size of the universe was 4 Light years (radius - 2 light years):

 

1 second

1x10¹⁰

4 light-years

 

 

So, if after one year the radius of the Universe was 2 Light year, then we could assume that the velocity is double than the speed of light.

 

But here – after just one second…

 

1 year = 31 556 926 seconds

Hence, the velocity of the plasma is:

 

V = 31 556 926 * 2 =  6,311,384 Light speed.

 

Is it real?

We know that nothing can move higher than a speed of light.

So, How could it be? 

Even I understand this now, thanks to the research on the big bang that you have made me do!

 

The point is that it was spacetime itself that was expanding: the metric itself. Relativity precludes anything moving faster than light through space,

i.e. as measured by means of distance gone in unit time. If the metric itself is expanding, i.e. units of distance themselves are expanding, all bets are off: there is nothing to prevent this. You will find this explained in any decent web article on the big bang - it did not take me long. Try the Wiki one. 

 

I am frankly rather surprised that a person with your degree of professed interest in this topic would not have already realised this.   

 

P.S. I am a bit sceptical about all this stuff about the universe being "the size of a grapefruit" etc. From what I have now read on this, I suspect what is meant is the size of the observable universe, which is different. This is because it was the metric itself that was expanding: the "size" of the whole universe cannot be defined except in relation to some metric existing outside it, which seems nonsensical. 

 

But I am willing to bow to the superior knowledge of anyone here with an astrophysics background, as this is stuff I have only read up in the last week or so. 

[davdan]

Even I understand this now, thanks to the research on the big bang that you have made me do!

 

The point is that it was spacetime itself that was expanding: the metric itself. Relativity precludes anything moving faster than light through space,

i.e. as measured by means of distance gone in unit time. If the metric itself is expanding, i.e. units of distance themselves are expanding, all bets are off: there is nothing to prevent this. You will find this explained in any decent web article on the big bang - it did not take me long. Try the Wiki one. 

 

Well, with regards to the expansion:

 

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

 

the expansion of the universe has been measured using redshift to derive Hubble's Constant: H₀ = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second

 

You have to distinguish between short range and long rang.

A 4 Ly is considered as a very short range.

In this range the effect of the expansion is almost neglected.

 

So please show me how can we achieve a speed of 6,311,384 Light speed at any sort of space expansion.

If you can, please try to set a mathematical calculation.

[exchemist]

Well, with regards to the expansion:

 

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

 

the expansion of the universe has been measured using redshift to derive Hubble's Constant: H₀ = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second

 

You have to distinguish between short range and long rang.

A 4 Ly is considered as a very short range.

In this range the effect of the expansion is almost neglected.

 

So please show me how can we achieve a speed of 6,311,384 Light speed at any sort of space expansion.

If you can, please try to set a mathematical calculation.

All I am pointing out is that faster than light expansion is not prohibited if it is the metric itself that expands. Are you now OK with that concept?    

[davdan]

All I am pointing out is that faster than light expansion is not prohibited if it is the metric itself that expands. Are you now OK with that concept?    

 

That Idea can give an explanation for the high speed (close to speed of light) of galaxies at the far end of the Universe.

 

However, it can't explain a speed of 6,311,384 Light speed.

So how can you accept the idea of such unrealistic speed?

Edited June 5, 2017 by davdan

[exchemist]

That Idea can give an explanation for the high speed (close to speed of light) of galaxies at the far end of the Universe.

 

However, it can't explain a speed of 6,311,384 Light speed.

So how can you accept the idea of such unrealistic speed?

Wrong. It makes faster than light speed expansion possible. Do you not understand that? 

Edited June 5, 2017 by exchemist

[davdan]

In any case, when the unive

 

Wrong. It makes faster than light speed expansion possible. Do you not understand that? 

 

 

How faster?

Do you mean that the space expansion is 6 Million faster than the speed of light?

I couldn't find any indication for that kind of expansion speed.

Edited June 5, 2017 by davdan

[exchemist]

In any case, when the unive

 

 

 

How faster?

Do you mean that the space expansion is 6 Million faster than the speed of light?

I couldn't find any indication for that kind of expansion speed.

Once you concede that faster than light expansion is possible, what basis do you have for saying that any particular speed is too fast? There are no other speed limits that I am aware of. Are you? 

[davdan]

Once you concede that faster than light expansion is possible, what basis do you have for saying that any particular speed is too fast? There are no other speed limits that I am aware of. Are you? 

 

We are speaking about a theory.

 

Based on the BBT the space expansion is only 67 kilometers per second.

I have no problem that they will claim that it is faster.

They could say that the space expansion is as high as 6 Million Light speed.

In this case, we all must agree with the outcome.

However, currently our scientists insist on 67 kilometers per second.

Therefore, as long as this is the upper limit of the space expansion - a 6 Million speed of light is just not feasible.

 

Why don't you agree with that?

Edited June 5, 2017 by davdan

[exchemist]

 

We are speaking about a theory.

 

Based on the BBT the space expansion is only 67 kilometers per second.

I have no problem that they will claim that it is faster.

They could say that the space expansion is as high as 6 Million Light speed.

In this case, we all must agree with the outcome.

However, currently our scientists insist on 67 kilometers per second.

Therefore, as long as this is the upper limit of the space expansion - a 6 Million speed of light is just not feasible.

 

Why don't you agree with that?

 

You are now suddenly introducing a speed limit of 67km/sec, which is 0.02% of the speed of light. Where do you get this figure from?   

[davdan]

Well, with regards to the expansion:

 

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

 

the expansion of the universe has been measured using redshift to derive Hubble's Constant: H₀ = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second

Edited June 5, 2017 by davdan

[exchemist]

 

Well, with regards to the expansion:

 

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

 

the expansion of the universe has been measured using redshift to derive Hubble's Constant: H₀ = 67.15 ± 1.2 (km/s)/Mpc. For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second

 

 

Firstly that is not a rate of expansion, but the change in the rate of expansion with distance from the observer. 

 

Secondly, it is the rate of change measured currently. It tells you nothing about the rate of expansion in the so-called inflationary epoch.

 

You can read about this here: https://en.wikipedia.org/wiki/Inflationary_epoch

[davdan]

In the article there is clear information about the inflationary epoch as it is stated:

 

"In physical cosmology the inflationary epoch was the period in the evolution of the early universe when, according to inflation theory, the universe underwent an extremely rapid exponential expansion. This rapid expansion increased the linear dimensions of the early universe by a factor of at least 10²⁶ (and possibly a much larger factor), and so increased its volume by a factor of at least 10⁷⁸. Expansion by a factor of 10²⁶ is equivalent to expanding an object 1 nanometer (10^-9 m, about half the width of a molecule of DNA) in length to one approximately 10.6 light years (about 62 trillion miles) long.

The expansion is thought to have been triggered by the phase transition that marked the end of the preceding grand unification epoch at approximately 10⁻³⁶ seconds after the Big Bang. One of the theoretical products of this phase transition was a scalar field called the inflaton field. As this field settled into its lowest energy state throughout the universe, it generated a repulsive force that led to a rapid expansion of space. This expansion explains various properties of the current universe that are difficult to account for without such an inflationary epoch."

 

However, it is also stated when it ends:

"It is not known exactly when the inflationary epoch ended, but it is thought to have been between 10⁻³³ and 10⁻³² seconds after the Big Bang."

 

At that moment, the size of the universe was as big as grapefruit:

 

"Inflationary Epoch, from 10^–36 seconds to 10^–32 seconds:
Triggered by the separation of the strong nuclear force, the universe undergoes an extremely rapid exponential expansion, known as cosmic inflation. The linear dimensions of the early universe increases during this period of a tiny fraction of a second by a factor of at least 10^26 to around 10 centimeters (about the size of a grapefruit)."

 

So how can we explain the expansion from a grapefruit size to 4 light year size (in the first second)?