Did all 10^80 particles exist after the first 3 minutes?

[g.lemaitre]

I'm a little skeptical that all 10^80 particles could fit inside a universe as small as it was after the 3rd minute. I know there is a lot of empty space inside a particle so maybe in the beginning that empty space was not there, but I'm still skeptical. I'm still confused about whether or not the conversation of baryon number really holds. Is it ever the case that virtual particle get promoted to real particle hood, after the 3rd minute? Here's a passage from Paul Davies' The Last Three Minutes:

When the false vacuum has decayed, the universe resumes its normal decelerating expansion. The energy that had been locked up in the false vacuum is released, appearing in the form of heat. The huge distension produced by inflation had cooled the universe to a temperature very close to absolute zero; suddenly, the termination of inflation reheats it to a prodigious 10^28 degrees. This vast reservoir of heat survives today, in grossly diminished form, as the cosmic background heat radiation.
A by-product of the release of the vacuum energy is that many virtual particles in the quantum vacuum receive some of it and get promoted to real particlehood. After further processing and changes, a remnant of these primordial particles went on to provide the 10^50 tons of matter that makes up you, me, the galaxy, and the rest of the observable universe.
If the inflationary scenario is on the right track—and many leading cosmologists believe that it is—then the basic structure and physical contents of the universe were determined by processes that were complete after a mere 10^32 seconds had elapsed. The postinflationary universe underwent many additional changes at the subatomic level, as the primeval material developed into the particles and atoms that constitute the cosmic stuff of our epoch, but most of the additional processing of matter was complete after only three minutes or so.

And here is a quote from Steven Weinberg's The First Three Minutes concerning the conservation of Baryon number:

There are believed to be just three conserved quantities whose densities must be specified in our recipe for the early universe:
...
2. Baryon Number. “Baryon” is an inclusive term which includes the nuclear particles, protons and neutrons, together with somewhat heavier unstable particles known as hyperons. Baryons and antibaryons can be created or destroyed in pairs; and baryons can decay into other baryons, as in the “beta decay” of a radioactive nucleus in which a neutron changes into a proton, or vice versa. However, the total number of baryons minus the number of antibaryons (antiprotons, an-tineutrons, antihyperons) never changes.

Again, I find this hard to believe. How could all 10^80 particles fit into such a small size? But yet S.W. says it right there in black and white.

Also, are hyperons some jargon from the 70's that no one uses anymore?

 

[Number Nine]

Particle physics/cosmology is far from my forte, but I will point out that we don't know the size of the Universe at the third minute; it may very well have been infinite (which it must have been if the present Universe is infinite in size, which is by no means settled).

 

[Shovel]

Particle physics/cosmology is far from my forte, but I will point out that we don't know the size of the Universe at the third minute; it may very well have been infinite (which it must have been if the present Universe is infinite in size, which is by no means settled).

I believe the OP's 10^80 number refers to the number of particles in the observable portion of the universe - which is always finite regardless of whether or not the whole of the universe is infinite or not.

 

[g.lemaitre]

I believe the OP's 10^80 number refers to the number of particles in the observable portion of the universe - which is always finite regardless of whether or not the whole of the universe is infinite or not.

Yes, I'm referring to the observable portion.

 

[g.lemaitre]

Here's a quote from Weinberg on the size of the Early universe

It is natural to ask how large the universe was at very early times. Unfortunately we do not know, and we are not even sure that this question has any meaning. As indicated in Chapter II, the universe may well be infinite now, in which case it was also infinite at the time of the first frame, and will always be infinite. On the other hand, it is possible that the universe now has a finite circumference, sometimes estimated to be about 125 thousand million light years. (The circumference is the distance one must travel in a straight line before finding oneself back where one started. This estimate is based
on the present value of the Hubble constant, under the supposition that the density of the universe is about twice its “critical” value.) Since the temperature of the universe falls in inverse proportion to its size, the circumference of the universe at the time of the first frame was less than at present by the ratio of the temperature then (10^11 ° K) to the present temperature (3° K); this gives a first-frame circumference of about four light years. None of the details of the story of cosmic evolution in the first few minutes will depend on whether the circumference of the universe was infinite or only a few light years.

I don't see how they can figure out the temperature of the early universe unless they know the size.

 

[Chronos]

The size of the universe was around 50 light years 3 minutes after the big event. That may not seems like much, but, 50 light years is a lot of space and the universe was still expanding rapidly. Still, it was hot and crowded - enough so that primordial nucleosynthesis continued for another dozen or so minutes.

 

[mfb]

@Chronos: The size of the observable universe.10^80 particles in a ball with 50ly diameter (?), neglecting curvature, is ~1/nm^3, which is less than the density of atoms in solid objects. And if you compare regular matter with neutron stars, there is a lot of space left, even if the particles would be solid objects (they are not). While Fermions cannot occupy the same state with multiple particles, if you increase the energy you also increase the available states and therefore the allowed density - without a theoretical limit.

Also, are hyperons some jargon from the 70's that no one uses anymore?

Still used

 

[Chalnoth]

10^80 particles in a ball with 50ly diameter (?), neglecting curvature, is ~1/nm^3, which is less than the density of atoms in solid objects. And if you compare regular matter with neutron stars, there is a lot of space left, even if the particles would be solid objects (they are not). While Fermions cannot occupy the same state with multiple particles, if you increase the energy you also increase the available states and therefore the allowed density - without a theoretical limit.

This shouldn't be a surprise. This was long before atoms formed, when our universe was just transitioning from a quark-gluon plasma as protons and neutrons first started forming.

 

[g.lemaitre]

do string theorists believe there is one string with width 10^-35 m inside one quark with width 10^-19 m? If so then it would be slightly easier to imagine all matter compacted inside a very small space?

 

[Mark M]

do string theorists believe there is one string with width 10^-35 m inside one quark with width 10^-19 m? If so then it would be slightly easier to imagine all matter compacted inside a very small space?

No. In string theory all particles are strings. They aren't made of strings, they literally are strings. In the SM, particles have no size, they're zero dimensional. I'm not sure where you got that number, but it is most likely how far we can confirm the quark has no size.

 

[mfb]

The 10^(-19)m is just an upper limit. If it would be larger than that, we would have seen a substructure. It is impossible to give a lower limit.

 

[Dotini]

I'm a little skeptical that all 10^80 particles...

Doesn't pair production mean that more particles are being created all the time, even as energy is being conserved?

Respectfully submitted,
Steve

 

[Chalnoth]

Doesn't pair production mean that more particles are being created all the time, even as energy is being conserved?

Well, when our universe was at extremely high temperatures, particles would be produced just as often as they would annihilate with one another. As our universe cooled so that the production rate slowed, they would tend to annihilate with one another more than they would be produced, reducing the number of particles.

 

[Mark M]

Doesn't pair production mean that more particles are being created all the time, even as energy is being conserved?

Respectfully submitted,
Steve

The OP is referring to Baryons, particles produced in the early universe that are made of quarks (protons, neutrons, etc.). This doesn't include elementary particles (e.g. the leptons)

 

[g.lemaitre]

No. In string theory all particles are strings. They aren't made of strings, they literally are strings. In the SM, particles have no size, they're zero dimensional. I'm not sure where you got that number, but it is most likely how far we can confirm the quark has no size.

I meant that the string's size is 10^-35 m and its Pauli Exclusion domain is 10^-19 m. I got the size of quarks from wiki's article of orders of magnitude


http://en.wikipedia.org/wiki/Orders_of_magnitude_(length))

Maybe the size of the Pauli Exlusion domain was different during the first few seconds.

 

[clamtrox]

We know from accelerator physics that baryon number is conserved in interactions between particles for collision energies that existed in 3-minute-old universe. Therefore the particles must have been created earlier, to account for the fact that there is more baryons than antibaryons around.