What was energy of universe at big bang?

[Unes]

By the way are you concerned that our current ideas of the origin of the universe looks so much like a stock market bubble? If it proves wrong, sociologists are going to have a field day.

Thank you sayak83 & Polymath257, for me, your posts put a bright light on getting a notion of the inflation theory.

Since there are few versions of inflation theory, then it seems the inflation theory has not been settled yet to everybody’s satisfaction, and I assume there is no verifiable experiment yet. Am I correct on this point?

So, during the inflation, a lot of Positive and Negative energy were produced. Did this generating Positive and Negative energy continue after the inflation? Or, after the inflation it stopped generating, and universe got all the particles that we are observing today?

 

[Polymath257]

Thank you sayak83 & Polymath257, for me, your posts put a bright light on getting a notion of the inflation theory.

Since there are few versions of inflation theory, then it seems the inflation theory has not been settled yet to everybody’s satisfaction, and I assume there is no verifiable experiment yet. Am I correct on this point?

So, during the inflation, a lot of Positive and Negative energy were produced. Did this generating Positive and Negative energy continue after the inflation? Or, after the inflation it stopped generating, and universe got all the particles that we are observing today?

Inflation explains a number of things we observe: spatial flatness, the horizon problem, etc, but the signature of inflation (tensor fluctuations) have not been found yet. There was a report by BICEPII claiming to see this signature, but it turned out to be local gas clouds.

Inflation is a particularly fast expansion produced by some particle (possibly the Higgs, but not verified to be) moving towards a lower energy state that has more of that particle. After that particle decays, you get the production of the rest of what we see around us. There is still negative energy from the gravity, though.

 

[sayak83]

Thank you sayak83 & Polymath257, for me, your posts put a bright light on getting a notion of the inflation theory.

Since there are few versions of inflation theory, then it seems the inflation theory has not been settled yet to everybody’s satisfaction, and I assume there is no verifiable experiment yet. Am I correct on this point?

So, during the inflation, a lot of Positive and Negative energy were produced. Did this generating Positive and Negative energy continue after the inflation? Or, after the inflation it stopped generating, and universe got all the particles that we are observing today?

Since the universe is expanding and the current vacuum has a small but non zero energy, the total energy of the universe is increasing and will continue to increase indefinitely, with the gravitational energy becoming more negative as well. But none of it is transferring itself to matter or radiation, it's staying in space-time and will do so unless this vacuum also decays into something else. Nobody knows if that can happen or not. Nothing suggests it. But if it happens all of us will disintegrate into hot soup in a zeptosecond. So I hope not.

There is observational evidence for inflation or something that mimics inflation. Because the universe expanded so fast so quickly, inherent quantum fluctuations if the inflation field, which would have been teeny tiny under ordinary conditions, also expanded into cosmic levels of scale in a zeptosecond. When inflation ended this expanded out potential fluctuations became fluctuations of energy density in ordinary matter and radiation. Because of its quantum origins, inflation predicts how they will look, and that predictions matches up with the fluctuations that we see in the cosmic microwave background radiation. So that's a good test, especially as the fluctuations were predicted 15 years before the results came in and validated it. The thing is "some sort of repulsive force expanded space very fast very quickly" does fix the sort of field that caused it to happen. So there are many equally feasible variants of the basic idea at play. More observations needed to know which one exactly is correct.

You should look at my posts on this on the thread below and what @Polymath257 has said as well.
Singularities and beginning of the universe

I think there has to some sort of an inflationary event to explain the features of the universe and while a scalar field that causes repulsive gravity is the most favored cause of this event, other possibilities exist as well.

 

[Jake1001]

Does spatial flatness require the universe being a hologram ??

Inflation explains a number of things we observe: spatial flatness, the horizon problem, etc, but the signature of inflation (tensor fluctuations) have not been found yet. There was a report by BICEPII claiming to see this signature, but it turned out to be local gas clouds.

Inflation is a particularly fast expansion produced by some particle (possibly the Higgs, but not verified to be) moving towards a lower energy state that has more of that particle. After that particle decays, you get the production of the rest of what we see around us. There is still negative energy from the gravity, though.

 

[Polymath257]

Does spatial flatness require the universe being a hologram ??

No.

 

[viole]

Does spatial flatness require the universe being a hologram ??

No. 3 dimensional things can be flat.

Ciao

- viole

 

[sayak83]

Does spatial flatness require the universe being a hologram ??

Here flat does not mean 2D. In general relativity space-time can be curved in 3 dimensions. What flatness means here is that on the largest scales (I. E. away from stars and other local heavy masses) Space is not curved but is Eucledian.
This post below is a good one.
What Do You Mean, the Universe Is Flat? Part II: In Which We Actually Answer the Question

 

[Unes]

Why quantum gravity?

The problem with a gravitational singularity is that it compresses all matter with its positional, momenta, energy and other properties into smaller and smaller volumes. But as quantum uncertainty principle notes, this is simply not possible. Thus there will come a time before which quantum considerations will override the classical predictions of GR.
What is that point? Here is a brief scale analysis. Universe has a certain amount of mass-energy. Mass and energy has a quantum wavelength associated with it (just like an electron has a wavelength associated with it). When the dimensions of the universe was smaller than the dimension of this wavelength, quantum considerations necessarily overwhelm classical relativity. This corresponds to when the visible universe was just 10^-33 cm across. While quantum effects can exist at much larger scale, this is the minimum scale at which QG has to necessarily apply. The density of the universe at this point would be 10^94 gm/cc. Light takes about 10^-43 seconds to traverse a sphere 10^-33 cm across and this is conveniently called the Planck epoch time.

The challenge for quantum gravity is to determine what physics holds under these extreme conditions.

In this passage from your thread "Singularities and beginning of the universe" you are saying: "The density of the universe at this point would be 10^94 gm/cc. "
As the energy of universe is supposed to be close to zero, then here, why you are disregarding the Negative energy? As if the Negative energy does not exist!

 

[sayak83]

In this passage from your thread "Singularities and beginning of the universe" you are saying: "The density of the universe at this point would be 10^94 gm/cc. "
As the energy of universe is supposed to be close to zero, then here, why you are disregarding the Negative energy? As if the Negative energy does not exist!

It's not being disregarded, it's there as gravitational potential energy exactly balancing the positive energy density. But when cosmologists speak of energy density anywhere, they talk only about the positive part. When they want to speak about the negative gravitational potential energy, they speak about it separately. For example, when an astrophysicist talks about the energy density of the sun, he is excluding the negative energy of its gravitational potential we'll and only about the energy present in its radiation and matter. Same convention here.

Bottom line energy density means the positive part of the energy which is vacuum energy+energy of various radiations and matter.

 

[Jake1001]

Does it preclude it being a hologram ??

What about a computer simulation ?? How do you know you are not a simulation ??

No. 3 dimensional things can be flat.

Ciao

- viole

 

[Unes]

Transforming photons to electron or proton coincides with creation of positron or anti-proton. Does creation of Positive energy particles in Inflation theory also REQUIRE the production of anti-particles at the same time?

 

[sayak83]

Transforming photons to electron or proton coincides with creation of positron or anti-proton. Does creation of Positive energy particles in Inflation theory also REQUIRE the production of anti-particles at the same time?

Anti matter like positions also have positive energy.

It would if charge and parity was strictly conserved. But it has been observed that several physical processes do not strictly conserve charge and parity symmetry. So the current theory is that due to this slight asymmetry, for every 1 billion anti-particles, 1 billion and one particles were produced. This slight excess of particles was enough to create our universe.

Fortuitously, here is something interesting
https://phys.org/news/2017-01-source-asymmetry-antimatter.html

 

[viole]

Does it preclude it being a hologram ??

Nope. But it does not necessitate it.

What about a computer simulation ?? How do you know you are not a simulation ??

I am not certain that I am not a simulation. But I am not certain of basically anything.

Ciao

- viole

 

[Unes]

It would if charge and parity was strictly conserved. But it has been observed that several physical processes do not strictly conserve charge and parity symmetry. So the current theory is that due to this slight asymmetry, for every 1 billion anti-particles, 1 billion and one particles were produced. This slight excess of particles was enough to create our universe.

Fortuitously, here is something interesting
https://phys.org/news/2017-01-source-asymmetry-antimatter.html

Thank you sayak83,
When you say: “for every 1 billion anti-particles, 1 billion and one particles were produced”, are the produced particle & anti-particle keep annihilating each other with fast rate, that we end up with the universe that it is filled only with the regular particles? Or, both particle and anti-particle continue to exist, in that 10^94 gm/cc energy density that you mentioned before?

 

[sayak83]

Thank you sayak83,
When you say: “for every 1 billion anti-particles, 1 billion and one particles were produced”, are the produced particle & anti-particle keep annihilating each other with fast rate, that we end up with the universe that it is filled only with regular particle? Or, both particle and anti-particle continue to exist, in that 10^94 gm/cc energy density that you mentioned before?

The particles and anti-particles eventually annihilated each other creating photons. There are roughly 1 billion photons for every 1 baryon (quarks and electron) that make up matter. That's how the photons were created. Some more are being created afterwards in the stars of course, but that's still a blip against the initial "light" of the Big Bang era.

 

[Unes]

But now the entire space has a set of nonzero Higgs field values. And this nonzero Higgs field now interacts with the electron, quark and neutrino fields. The interaction between the fields differ from each other, causing them now behave differently from each other. Thus now the symmetry between them is broken-electrons, quarks and neutrinos- resonating in a different way with the Higgs fields- now look very different and also gain different masses from one another (when originally they were massless).

Hi satak83, I got this quote from your thread: Singularities and beginning of the universe
The mass property of a particle is the value that it is related to its interaction with the gravity field, then, why does the interaction with Higgs boson field is equally related to the mass property of the particle? As you explained earlier gravity field and Higgs boson field are two different kinds of fields, one is vector, and the other is scalar.

 

[sayak83]

Hi satak83, I got this quote from your thread: Singularities and beginning of the universe
The mass property of a particle is the value that it is related to its interaction with the gravity field, then, why does the interaction with Higgs boson field is equally related to the mass property of the particle? As you explained earlier gravity field and Higgs boson field are two different kinds of fields, one is vector, and the other is scalar.

Very crudely, Higgs field causes elementary particles to have mass, while mass bends space-time causing gravitational forces.

 

[Unes]

Very crudely, Higgs field causes elementary particles to have mass, while mass bends space-time causing gravitational forces.

Thank you satak83,
In GR we define mass as a curvature of space-time, but in the standard model we define graviton as the boson for the gravity field. What type of field is gravity? Is it vector or scalar, or it is something else?

 

[sayak83]

Thank you satak83,
In GR we define mass as a curvature of space-time, but in the standard model we define graviton as the boson for the gravity field. What type of field is gravity? Is it vector or scalar, or it is something else?

No no. Gravity is curvature of space-time. Not mass. The curvature has a magnitude and a direction, so it's a vector field.

 

[sayak83]

Thank you satak83,
In GR we define mass as a curvature of space-time, but in the standard model we define graviton as the boson for the gravity field. What type of field is gravity? Is it vector or scalar, or it is something else?

These two articles are excellent and clarify the inflationary theory
Cosmic Inflation’s Five Great Predictions – Starts With A Bang! – Medium


http://scienceblogs.com/startswithabang/2011/10/28/why-we-think-theres-a-multiver/