The very first structures in the Universe

The first moments of the Universe can be reconstructed mathematically even though they cannot be observed directly. Physicists have greatly improved the ability of complex computer simulations to describe this moment, discovering that a complex network of structures can form in the first trillionth of a second after the Big Bang. These microscopic clumps have masses of only a few grams and fit into volumes much smaller than particles.

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Tau.Neutrino said:

The very first structures in the Universe

The first moments of the Universe can be reconstructed mathematically even though they cannot be observed directly. Physicists have greatly improved the ability of complex computer simulations to describe this moment, discovering that a complex network of structures can form in the first trillionth of a second after the Big Bang. These microscopic clumps have masses of only a few grams and fit into volumes much smaller than particles.

more…

This article is … weird.

I’ll start from personal knowledge, and expand it to what the article talks about.

From personal knowledge, the simulation of the first structures in the universe is easy, the simulation of the later structures (such as the formation of galaxy clusters) is hard. This is in the same way that the simulation of the early stages of breakdown from laminar to turbulent flow is easy and the simulation of later stages of the breakdown from laminar to turbulent flow is hard.

In addition, the simulation of of the first structures in the universe yields results which are observable in the cosmic microwave background and in its power spectrum.

But now this article is claiming the opposite, that the simulation of the first structures in the universe is difficult and that these structures cannot be observed.

> a complex network of structures can form in the first trillionth of a second after the Big Bang

That’s 10^-12 seconds, well after the period of cosmic inflation, which finished at 10^-33 to 10^-32 seconds after the big bang. I would have thought that it wouldn’t be complex back then?

> The physical space represented by our simulation would fit into a single proton a million times over

Good. Nice to see that confirmed. I had heard that decades ago but had never seen it confirmed.

> The early Universe may have passed through an extended period of matter-dominated expansion following inflation and prior to the onset of radiation domination.

Noted. I had not heard that. But it makes sense. I wish they hadn’t said “may have”, it leaves me still uncertain.

> The strong analogy between this phase and structure formation in the present-day Universe allows the use of N-body simulations and approximate methods for halo formation to model the fragmentation of the inflaton condensate into inflaton halos.

Oik.

TATE tells me that the CMBR that we can observe dates from about 300,000 years after the big bang.

The idea that we can extrapolate backwards from this earliest observable data, and that the results are a reliable indication of what actually happened, no matter how close to zero the time is, seems ridiculous to me.

The Rev Dodgson said:

TATE tells me that the CMBR that we can observe dates from about 300,000 years after the big bang.

The idea that we can extrapolate backwards from this earliest observable data, and that the results are a reliable indication of what actually happened, no matter how close to zero the time is, seems ridiculous to me.

Could we observe anything earlier as our technology improves I wonder
Perhaps simulations are the best we can get as they match what we see know

Cymek said:

The Rev Dodgson said:

TATE tells me that the CMBR that we can observe dates from about 300,000 years after the big bang.

The idea that we can extrapolate backwards from this earliest observable data, and that the results are a reliable indication of what actually happened, no matter how close to zero the time is, seems ridiculous to me.

Could we observe anything earlier as our technology improves I wonder
Perhaps simulations are the best we can get as they match what we see know

I believe we do experiments with colliders that simulate conditions that occurred shortly after the BB.

The Rev Dodgson said:

TATE tells me that the CMBR that we can observe dates from about 300,000 years after the big bang.

The idea that we can extrapolate backwards from this earliest observable data, and that the results are a reliable indication of what actually happened, no matter how close to zero the time is, seems ridiculous to me.

Why ridiculous?

Take the transition from laminar to turbulent flow. If given a turbulent flow shortly after that transition then we can extrapolate backwards by filtering out the smaller scales to get a reliable indication of what happened earlier to the transition.

JudgeMental said:

Cymek said:

The Rev Dodgson said:

TATE tells me that the CMBR that we can observe dates from about 300,000 years after the big bang.

The idea that we can extrapolate backwards from this earliest observable data, and that the results are a reliable indication of what actually happened, no matter how close to zero the time is, seems ridiculous to me.

Could we observe anything earlier as our technology improves I wonder
Perhaps simulations are the best we can get as they match what we see know

I believe we do experiments with colliders that simulate conditions that occurred shortly after the BB.

I have never seen any indication of how close to the BB the LHC can simulate.

But even if it is very close, observing the outcome of a very small number of particles interacting is not simulating a Universe (or even a complex structure within a Universe).

The Rev Dodgson said:

JudgeMental said:

Cymek said:

Could we observe anything earlier as our technology improves I wonder
Perhaps simulations are the best we can get as they match what we see know

I believe we do experiments with colliders that simulate conditions that occurred shortly after the BB.

I have never seen any indication of how close to the BB the LHC can simulate.

But even if it is very close, observing the outcome of a very small number of particles interacting is not simulating a Universe (or even a complex structure within a Universe).

LOL.

mollwollfumble said:

The Rev Dodgson said:

TATE tells me that the CMBR that we can observe dates from about 300,000 years after the big bang.

The idea that we can extrapolate backwards from this earliest observable data, and that the results are a reliable indication of what actually happened, no matter how close to zero the time is, seems ridiculous to me.

Why ridiculous?

Take the transition from laminar to turbulent flow. If given a turbulent flow shortly after that transition then we can extrapolate backwards by filtering out the smaller scales to get a reliable indication of what happened earlier to the transition.

Extrapolating to the BB from the CMBR is like extrapolating back to the spring at the head of a river from the erosion in the bank of the flood plain, years after the flood that caused it has passed.

Only much more so.

JudgeMental said:

The Rev Dodgson said:

JudgeMental said:

I believe we do experiments with colliders that simulate conditions that occurred shortly after the BB.

I have never seen any indication of how close to the BB the LHC can simulate.

But even if it is very close, observing the outcome of a very small number of particles interacting is not simulating a Universe (or even a complex structure within a Universe).

LOL.

Why do you laugh dear sir?

The Rev Dodgson said:

JudgeMental said:

The Rev Dodgson said:

I have never seen any indication of how close to the BB the LHC can simulate.

But even if it is very close, observing the outcome of a very small number of particles interacting is not simulating a Universe (or even a complex structure within a Universe).

LOL.

Why do you laugh dear sir?

Talking to yourself is only the first sign.

The Rev Dodgson said:

JudgeMental said:

The Rev Dodgson said:

I have never seen any indication of how close to the BB the LHC can simulate.

But even if it is very close, observing the outcome of a very small number of particles interacting is not simulating a Universe (or even a complex structure within a Universe).

LOL.

Why do you laugh dear sir?

at you continual use of the logical fallacy or personal incredulity.

The Rev Dodgson said:

JudgeMental said:

The Rev Dodgson said:

I have never seen any indication of how close to the BB the LHC can simulate.

But even if it is very close, observing the outcome of a very small number of particles interacting is not simulating a Universe (or even a complex structure within a Universe).

LOL.

Why do you laugh dear sir?

“The LHC will collide particles using the highest kinetic energies that are currently technically possible (these energies correspond to those that are calculated to have existed 10-12 seconds after the Big Bang), crashing the particles into each other with close to the speed of light. This should result in new particles of higher mass than any previous experiments have achieved, allowing the physicists to test their ideas. Despite suggestions by the media, however, the energy of collisions in the LHC will be about 1075 times lower than in the Big Bang, so fears that a ‘Small Bang’ could be recreated are unfounded.”

https://www.scienceinschool.org/2008/issue10/lhcwhy

The Rev Dodgson said:

The Rev Dodgson said:

JudgeMental said:

LOL.

Why do you laugh dear sir?

“The LHC will collide particles using the highest kinetic energies that are currently technically possible (these energies correspond to those that are calculated to have existed 10-12 seconds after the Big Bang), crashing the particles into each other with close to the speed of light. This should result in new particles of higher mass than any previous experiments have achieved, allowing the physicists to test their ideas. Despite suggestions by the media, however, the energy of collisions in the LHC will be about 1075 times lower than in the Big Bang, so fears that a ‘Small Bang’ could be recreated are unfounded.”

https://www.scienceinschool.org/2008/issue10/lhcwhy

yes, I know this. I believe with the LHC upgrades they get even higher energies and even further “back in time”. gotta love the laws of physics being so consistent.

JudgeMental said:

The Rev Dodgson said:

JudgeMental said:

LOL.

Why do you laugh dear sir?

at you continual use of the logical fallacy or personal incredulity.

Expression of personal incredulity is not a logical fallacy, it is an expression of personal incredulity (in this case backed up with a brief statement of the reasons for such incredulity).

Feel free to explain to all why my incredulity is not well founded.

anyway enough of this pointless discussion for me. might go whittle some wood.

JudgeMental said:

The Rev Dodgson said:

JudgeMental said:

LOL.

Why do you laugh dear sir?

at you continual use of the logical fallacy or personal incredulity.

Second sign is when you answer yourself.

roughbarked said:

JudgeMental said:

The Rev Dodgson said:

Why do you laugh dear sir?

at you continual use of the logical fallacy or personal incredulity.

Second sign is when you answer yourself.

Who do you think is answering/talking to him/her/itself?

The Rev Dodgson said:

roughbarked said:

JudgeMental said:

at you continual use of the logical fallacy or personal incredulity.

Second sign is when you answer yourself.

Who do you think is answering/talking to him/her/itself?

Realised after I said it that I was talking to myself.

roughbarked said:

The Rev Dodgson said:

roughbarked said:

Second sign is when you answer yourself.

Who do you think is answering/talking to him/her/itself?

Realised after I said it that I was talking to myself.

I’ll say nothing :)