t = 10^−37 seconds

Perpetual Student · 12th July 2009, 01:11 PM

According to Wikipedia:
" Based on measurements of the expansion using Type Ia supernovae, measurements of temperature fluctuations in the cosmic microwave background, and measurements of the correlation function of galaxies, the universe has a calculated age of 13.73 ± 0.12 billion years."

If I understand the prevailing model correctly, the tools provided by GR and QM allow cosmologists to model the universe as early as 10^-37s.
Again from Wikipedia:
"Approximately 10⁻³⁷ seconds into the expansion, a phase transition caused a cosmic inflation, during which the universe grew exponentially. ..."

My question concerns to degree of certainty about the model at the earliest times. It has been said that as t approaches 0, the mathematics of the model breaks down. (Do I understand that correctly?)
Assuming the above is correct, I am asking about the degree of certainty about small values of t where the mathematics is still viable. What experimental evidence is there to validate the physics at the unfathomable densities and temperatures at small values of t? Could it be that the model fails to reflect reality well before the mathematics breaks down -- the same way many useful physics models work well at a wide range of temperatures and pressures but fail at extreme conditions?
Is it possible that the model fails at, say, t = 10 minutes? Is there experimental evidence demonstrating the validity of the model at this early time? How confident are cosmologists of the validity of the model at this time and why?

sol invictus · 12th July 2009, 01:50 PM

Originally Posted by Perpetual Student

My question concerns to degree of certainty about the model at the earliest times. It has been said that as t approaches 0, the mathematics of the model breaks down. (Do I understand that correctly?)

Prior to approximately 10E-43s, the laws of physics become very uncertain. As for the mathematics itself... certainly if you extrapolate the known laws back to t=0 there is a problem - a singularity. Away from that, what happens is that certain quantities which today are too small to measure or constrain in any way would have been enormous and extremely important. Since we have no idea what those quantities are, we don't know what their relative importance was then, and so we can't say much. But it's not exactly a mathematical problem except right at t=0.

Quote:

Is it possible that the model fails at, say, t = 10 minutes? Is there experimental evidence demonstrating the validity of the model at this early time? How confident are cosmologists of the validity of the model at this time and why?

There is pretty solid experimental evidence starting from around 3 minutes (from big bang nucleosynthesis). It's by no means definitive, but it's good enough to rule out the vast majority of speculative modifications to the laws of physics one might propose. Before that time things are more uncertain, but as of today the evidence for inflation is fairly strong - which means we are almost sure it happened, but questions about exactly how, by what mechanism, how long it lasted, or how high the energy was aren't answered. Before inflation essentially nothing is known, although there are a few slight hints in the data of something interesting.

Are alternatives possible? Sure, one can never answer "no" to that question, because it's always possible one hasn't thought of every possibility. But, at least after a few minutes, it's very hard to find room among all the observational constraints for anything very different than the concordance model. But of course there are still very significant uncertainties even within the concordance model - the nature of dark matter and dark energy especially.

Perpetual Student · 12th July 2009, 03:59 PM

Originally Posted by sol invictus

Prior to approximately 10E-43s, the laws of physics become very uncertain. As for the mathematics itself... certainly if you extrapolate the known laws back to t=0 there is a problem - a singularity. Away from that, what happens is that certain quantities which today are too small to measure or constrain in any way would have been enormous and extremely important. Since we have no idea what those quantities are, we don't know what their relative importance was then, and so we can't say much. But it's not exactly a mathematical problem except right at t=0.

Thanks for your response. I was under the impression that QM and/or GR had problems at very small values of t sometime before the singularity. Is that not a fair way to interpret your saying that "the laws of physics become very uncertain" prior to 10E-43s? Why is that not a mathematical problem, since in some sense there does not appear to be anything but mathematics at this level? (One cannot actually experiment with t = 10E-43)

Quote:

There is pretty solid experimental evidence starting from around 3 minutes (from big bang nucleosynthesis). It's by no means definitive, but it's good enough to rule out the vast majority of speculative modifications to the laws of physics one might propose.

Is that experimental evidence mostly from experiments done with high energy collisions?

Quote:

Before that time things are more uncertain, but as of today the evidence for inflation is fairly strong - which means we are almost sure it happened, but questions about exactly how, by what mechanism, how long it lasted, or how high the energy was aren't answered. Before inflation essentially nothing is known, although there are a few slight hints in the data of something interesting.

Are alternatives possible? Sure, one can never answer "no" to that question, because it's always possible one hasn't thought of every possibility. But, at least after a few minutes, it's very hard to find room among all the observational constraints for anything very different than the concordance model. But of course there are still very significant uncertainties even within the concordance model - the nature of dark matter and dark energy especially.

Inflation is certainly a difficult concept for a layman. I have spent a good deal of time over the years reading at lot of material that is available for people like me (some mathematics, less physics). I feel I have no choice but to accept it on the authority of those who can actually evaluate the evidence. I know there is a lot of supporting observational evidence -- but, to your knowledge, is there any experimental evidence that even hints at inflation?

Cuddles · 13th July 2009, 07:44 AM

Originally Posted by Perpetual Student

Thanks for your response. I was under the impression that QM and/or GR had problems at very small values of t sometime before the singularity. Is that not a fair way to interpret your saying that "the laws of physics become very uncertain" prior to 10E-43s?

No, that's small values of t after the singularity. The singularity itself is at exactly t = 0.

Quote:

Why is that not a mathematical problem, since in some sense there does not appear to be anything but mathematics at this level? (One cannot actually experiment with t = 10E-43)

It's not a mathematical problem because there is no inherent problem with the maths itself at that point, only with the application of the maths to the real world, which makes it a physics problem. Since we can't actually experiment with that time (or equivalent conditions yet), it's a theoretical physics problem rather than experimental physics, but it's still physics (just don't tell any theorists I admitted they're real physicists).

sol invictus · 13th July 2009, 08:23 AM

Originally Posted by Perpetual Student

I was under the impression that QM and/or GR had problems at very small values of t sometime before the singularity.

Not really. "Singularity" means an infinity we don't know how to deal with. When we talk about t=0 in this context, it refers to the time at which there was such a singularity, and after which there wasn't.

Quote:

Is that not a fair way to interpret your saying that "the laws of physics become very uncertain" prior to 10E-43s? Why is that not a mathematical problem, since in some sense there does not appear to be anything but mathematics at this level? (One cannot actually experiment with t = 10E-43)

What Cuddles said. This may just be a semantic problem.

Quote:

Is that experimental evidence mostly from experiments done with high energy collisions?

That's a piece, but what I had in mind was primarily light element abundances in the universe.

Quote:

I know there is a lot of supporting observational evidence -- but, to your knowledge, is there any experimental evidence that even hints at inflation?

I don't think there's really a difference between experimental and observational evidence. But if you're asking whether we've produced an inflaton particle at an accelerator, or observed its effects in any other lab experiment, the answer is no.

Perpetual Student · 13th July 2009, 03:42 PM

Thanks. At times between t = 0 and t = 10E-43, is it that the model gives confusing, conflicting or nonsensical results? In other words, I am asking what is it about the model that does not work at these small values?

Quote:

s. i.: I don't think there's really a difference between experimental and observational evidence. But if you're asking whether we've produced an inflaton particle at an accelerator, or observed its effects in any other lab experiment, the answer is no.

I understand. There has been an (ad nauseum) debate about the distinction between experimental and observational evidence in one of the crackpot threads; that is not my purpose here. Now, I am curious if there is any theory involving fields, forces, particles (whatever) about the inflationary force that is consistent with the standard model of particle physics, and that could someday be confirmed with experimentation?

sol invictus · 13th July 2009, 03:50 PM

Originally Posted by Perpetual Student

Thanks. At times between t = 0 and t = 10E-43, is it that the model gives confusing, conflicting or nonsensical results? In other words, I am asking what is it about the model that does not work at these small values?

Pretty much everything "works" - it's just that there is more or less total uncertainty about what the theory and its parameters are.

Here's an analogy - suppose you approach the earth from space. You look out the window and see what looks like a nearly smooth sphere. Your job is to find a level, hard surface on which to land a meter-sized probe. All the information you have is what you can see out your window by eye and what you can work out mathematically.

Clearly your task is impossible, because from so far away you can't possibly distinguish forest from grass from sand on meter scales. There's nothing with your theories about planets, vegetation, surfaces - you just don't have enough information. Our theories about what came before 10E-43 s are like that - they're perfectly OK (down to t=0 itself), just not detailed enough to tell us much.

Quote:

Now, I am curious if there is any theory involving fields, forces, particles (whatever) about the inflationary force that is consistent with the standard model of particle physics, and that could someday be confirmed with experimentation?

Sure - plenty of 'em.

Michael Mozina · 13th July 2009, 05:00 PM

Originally Posted by Perpetual Student

I understand. There has been an (ad nauseum) debate about the distinction between experimental and observational evidence in one of the crackpot threads; that is not my purpose here. Now, I am curious if there is any theory involving fields, forces, particles (whatever) about the inflationary force that is consistent with the standard model of particle physics, and that could someday be confirmed with experimentation?

Not likely. Most folks assume/state that inflation has now ended (dead and gone) and therefore it would not show up today in a laboratory test no matter what we do.

Perpetual Student · 13th July 2009, 05:41 PM

Originally Posted by Michael Mozina

Not likely. Most folks assume/state that inflation has now ended (dead and gone) and therefore it would not show up today in a laboratory test no matter what we do.

I guess that would depend on the origin of the inflationary force. If is existed as a consequence of the high density and temperature of the universe at the time, perhaps that could be modeled on a tiny scale. On the other hand, that level of density and temperature may be unattainable.

SezMe · 13th July 2009, 05:51 PM

Originally Posted by Michael Mozina

Not likely. Most folks assume/state that inflation has now ended (dead and gone) and therefore it would not show up today in a laboratory test no matter what we do.

Sol and Cuddles, et. al., I'm sure, can be more helpful but I don't think that is true. As I understand it, we are at this moment, in an inflationary period. Well, maybe acceleration period. That is, the rate of expansion of the universe is increasing, not decreasing.

SezMe · 13th July 2009, 05:53 PM

On a different point, has theoretical physics looked at the possibility that time is quantized? That is, there is no such thing as time between 10e-43 and t=0? Somewhat like there is no such thing as an electron being between energy states.

Delvo · 13th July 2009, 06:40 PM

Originally Posted by SezMe

On a different point, has theoretical physics looked at the possibility that time is quantized? That is, there is no such thing as time between 10e-43 and t=0? Somewhat like there is no such thing as an electron being between energy states.

There is no certainty that time is unitized like that, but if it is, then the basic unit's value, the limit beyond which no meaningful calculations or reasoning can be applied, is about 5.4×10^-44. The (rounded off) number "10^-43" is about two of those units. In other words, our calculations only have a chance of being valid and making sense back to the second tick of the universe's clock. The first one is the one giving us the trouble.

12th July 2009, 01:11 PM	#1
Perpetual Student Illuminator Join Date: Jul 2008 Location: USA Posts: 3,707	t = 10^−37 seconds According to Wikipedia: " Based on measurements of the expansion using Type Ia supernovae, measurements of temperature fluctuations in the cosmic microwave background, and measurements of the correlation function of galaxies, the universe has a calculated age of 13.73 ± 0.12 billion years." If I understand the prevailing model correctly, the tools provided by GR and QM allow cosmologists to model the universe as early as 10^-37s. Again from Wikipedia: "Approximately 10⁻³⁷ seconds into the expansion, a phase transition caused a cosmic inflation, during which the universe grew exponentially. ..." My question concerns to degree of certainty about the model at the earliest times. It has been said that as t approaches 0, the mathematics of the model breaks down. (Do I understand that correctly?) Assuming the above is correct, I am asking about the degree of certainty about small values of t where the mathematics is still viable. What experimental evidence is there to validate the physics at the unfathomable densities and temperatures at small values of t? Could it be that the model fails to reflect reality well before the mathematics breaks down -- the same way many useful physics models work well at a wide range of temperatures and pressures but fail at extreme conditions? Is it possible that the model fails at, say, t = 10 minutes? Is there experimental evidence demonstrating the validity of the model at this early time? How confident are cosmologists of the validity of the model at this time and why?
	__________________ _{It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong. - Richard P. Feynman} ξ

12th July 2009, 01:50 PM	#2
sol invictus Philosopher Join Date: Oct 2007 Location: Nova Roma Posts: 8,419	Originally Posted by Perpetual Student My question concerns to degree of certainty about the model at the earliest times. It has been said that as t approaches 0, the mathematics of the model breaks down. (Do I understand that correctly?) Prior to approximately 10E-43s, the laws of physics become very uncertain. As for the mathematics itself... certainly if you extrapolate the known laws back to t=0 there is a problem - a singularity. Away from that, what happens is that certain quantities which today are too small to measure or constrain in any way would have been enormous and extremely important. Since we have no idea what those quantities are, we don't know what their relative importance was then, and so we can't say much. But it's not exactly a mathematical problem except right at t=0. Quote: Is it possible that the model fails at, say, t = 10 minutes? Is there experimental evidence demonstrating the validity of the model at this early time? How confident are cosmologists of the validity of the model at this time and why? There is pretty solid experimental evidence starting from around 3 minutes (from big bang nucleosynthesis). It's by no means definitive, but it's good enough to rule out the vast majority of speculative modifications to the laws of physics one might propose. Before that time things are more uncertain, but as of today the evidence for inflation is fairly strong - which means we are almost sure it happened, but questions about exactly how, by what mechanism, how long it lasted, or how high the energy was aren't answered. Before inflation essentially nothing is known, although there are a few slight hints in the data of something interesting. Are alternatives possible? Sure, one can never answer "no" to that question, because it's always possible one hasn't thought of every possibility. But, at least after a few minutes, it's very hard to find room among all the observational constraints for anything very different than the concordance model. But of course there are still very significant uncertainties even within the concordance model - the nature of dark matter and dark energy especially.
	Last edited by sol invictus; 12th July 2009 at 01:53 PM.

12th July 2009, 03:59 PM	#3
Perpetual Student Illuminator Join Date: Jul 2008 Location: USA Posts: 3,707	Originally Posted by sol invictus Prior to approximately 10E-43s, the laws of physics become very uncertain. As for the mathematics itself... certainly if you extrapolate the known laws back to t=0 there is a problem - a singularity. Away from that, what happens is that certain quantities which today are too small to measure or constrain in any way would have been enormous and extremely important. Since we have no idea what those quantities are, we don't know what their relative importance was then, and so we can't say much. But it's not exactly a mathematical problem except right at t=0. Thanks for your response. I was under the impression that QM and/or GR had problems at very small values of t sometime before the singularity. Is that not a fair way to interpret your saying that "the laws of physics become very uncertain" prior to 10E-43s? Why is that not a mathematical problem, since in some sense there does not appear to be anything but mathematics at this level? (One cannot actually experiment with t = 10E-43) Quote: There is pretty solid experimental evidence starting from around 3 minutes (from big bang nucleosynthesis). It's by no means definitive, but it's good enough to rule out the vast majority of speculative modifications to the laws of physics one might propose. Is that experimental evidence mostly from experiments done with high energy collisions? Quote: Before that time things are more uncertain, but as of today the evidence for inflation is fairly strong - which means we are almost sure it happened, but questions about exactly how, by what mechanism, how long it lasted, or how high the energy was aren't answered. Before inflation essentially nothing is known, although there are a few slight hints in the data of something interesting. Are alternatives possible? Sure, one can never answer "no" to that question, because it's always possible one hasn't thought of every possibility. But, at least after a few minutes, it's very hard to find room among all the observational constraints for anything very different than the concordance model. But of course there are still very significant uncertainties even within the concordance model - the nature of dark matter and dark energy especially. Inflation is certainly a difficult concept for a layman. I have spent a good deal of time over the years reading at lot of material that is available for people like me (some mathematics, less physics). I feel I have no choice but to accept it on the authority of those who can actually evaluate the evidence. I know there is a lot of supporting observational evidence -- but, to your knowledge, is there any experimental evidence that even hints at inflation?
	__________________ _{It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong. - Richard P. Feynman} ξ Last edited by Perpetual Student; 12th July 2009 at 04:49 PM.

13th July 2009, 07:44 AM	#4
Cuddles Decoy Moderator Join Date: Jul 2006 Location: A magical land full of pink fluffy sheeps and bunnies Posts: 16,597	Originally Posted by Perpetual Student Thanks for your response. I was under the impression that QM and/or GR had problems at very small values of t sometime before the singularity. Is that not a fair way to interpret your saying that "the laws of physics become very uncertain" prior to 10E-43s? No, that's small values of t after the singularity. The singularity itself is at exactly t = 0. Quote: Why is that not a mathematical problem, since in some sense there does not appear to be anything but mathematics at this level? (One cannot actually experiment with t = 10E-43) It's not a mathematical problem because there is no inherent problem with the maths itself at that point, only with the application of the maths to the real world, which makes it a physics problem. Since we can't actually experiment with that time (or equivalent conditions yet), it's a theoretical physics problem rather than experimental physics, but it's still physics (just don't tell any theorists I admitted they're real physicists).
	__________________ I am not a little teapot.

13th July 2009, 03:42 PM	#6
Perpetual Student Illuminator Join Date: Jul 2008 Location: USA Posts: 3,707	Thanks. At times between t = 0 and t = 10E-43, is it that the model gives confusing, conflicting or nonsensical results? In other words, I am asking what is it about the model that does not work at these small values? Quote: s. i.: I don't think there's really a difference between experimental and observational evidence. But if you're asking whether we've produced an inflaton particle at an accelerator, or observed its effects in any other lab experiment, the answer is no. I understand. There has been an (ad nauseum) debate about the distinction between experimental and observational evidence in one of the crackpot threads; that is not my purpose here. Now, I am curious if there is any theory involving fields, forces, particles (whatever) about the inflationary force that is consistent with the standard model of particle physics, and that could someday be confirmed with experimentation?
	__________________ _{It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong. - Richard P. Feynman} ξ

13th July 2009, 08:23 AM	#5
sol invictus Philosopher Join Date: Oct 2007 Location: Nova Roma Posts: 8,419	Originally Posted by Perpetual Student I was under the impression that QM and/or GR had problems at very small values of t sometime before the singularity. Not really. "Singularity" means an infinity we don't know how to deal with. When we talk about t=0 in this context, it refers to the time at which there was such a singularity, and after which there wasn't. Quote: Is that not a fair way to interpret your saying that "the laws of physics become very uncertain" prior to 10E-43s? Why is that not a mathematical problem, since in some sense there does not appear to be anything but mathematics at this level? (One cannot actually experiment with t = 10E-43) What Cuddles said. This may just be a semantic problem. Quote: Is that experimental evidence mostly from experiments done with high energy collisions? That's a piece, but what I had in mind was primarily light element abundances in the universe. Quote: I know there is a lot of supporting observational evidence -- but, to your knowledge, is there any experimental evidence that even hints at inflation? I don't think there's really a difference between experimental and observational evidence. But if you're asking whether we've produced an inflaton particle at an accelerator, or observed its effects in any other lab experiment, the answer is no.

13th July 2009, 03:50 PM	#7
sol invictus Philosopher Join Date: Oct 2007 Location: Nova Roma Posts: 8,419	Originally Posted by Perpetual Student Thanks. At times between t = 0 and t = 10E-43, is it that the model gives confusing, conflicting or nonsensical results? In other words, I am asking what is it about the model that does not work at these small values? Pretty much everything "works" - it's just that there is more or less total uncertainty about what the theory and its parameters are. Here's an analogy - suppose you approach the earth from space. You look out the window and see what looks like a nearly smooth sphere. Your job is to find a level, hard surface on which to land a meter-sized probe. All the information you have is what you can see out your window by eye and what you can work out mathematically. Clearly your task is impossible, because from so far away you can't possibly distinguish forest from grass from sand on meter scales. There's nothing with your theories about planets, vegetation, surfaces - you just don't have enough information. Our theories about what came before 10E-43 s are like that - they're perfectly OK (down to t=0 itself), just not detailed enough to tell us much. Quote: Now, I am curious if there is any theory involving fields, forces, particles (whatever) about the inflationary force that is consistent with the standard model of particle physics, and that could someday be confirmed with experimentation? Sure - plenty of 'em.

13th July 2009, 05:00 PM	#8
Michael Mozina Banned Join Date: Feb 2009 Posts: 9,362	Originally Posted by Perpetual Student I understand. There has been an (ad nauseum) debate about the distinction between experimental and observational evidence in one of the crackpot threads; that is not my purpose here. Now, I am curious if there is any theory involving fields, forces, particles (whatever) about the inflationary force that is consistent with the standard model of particle physics, and that could someday be confirmed with experimentation? Not likely. Most folks assume/state that inflation has now ended (dead and gone) and therefore it would not show up today in a laboratory test no matter what we do.
Michael Mozina Banned Join Date: Feb 2009 Posts: 9,362

13th July 2009, 05:41 PM	#9
Perpetual Student Illuminator Join Date: Jul 2008 Location: USA Posts: 3,707	Originally Posted by Michael Mozina Not likely. Most folks assume/state that inflation has now ended (dead and gone) and therefore it would not show up today in a laboratory test no matter what we do. I guess that would depend on the origin of the inflationary force. If is existed as a consequence of the high density and temperature of the universe at the time, perhaps that could be modeled on a tiny scale. On the other hand, that level of density and temperature may be unattainable.
	__________________ _{It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong. - Richard P. Feynman} ξ

13th July 2009, 05:51 PM	#10
SezMe post-pre-born Join Date: Dec 2003 Location: Santa Barbara, CA Posts: 16,367	Originally Posted by Michael Mozina Not likely. Most folks assume/state that inflation has now ended (dead and gone) and therefore it would not show up today in a laboratory test no matter what we do. Sol and Cuddles, et. al., I'm sure, can be more helpful but I don't think that is true. As I understand it, we are at this moment, in an inflationary period. Well, maybe acceleration period. That is, the rate of expansion of the universe is increasing, not decreasing.
	Last edited by SezMe; 13th July 2009 at 05:53 PM.

13th July 2009, 05:53 PM	#11
SezMe post-pre-born Join Date: Dec 2003 Location: Santa Barbara, CA Posts: 16,367	On a different point, has theoretical physics looked at the possibility that time is quantized? That is, there is no such thing as time between 10e-43 and t=0? Somewhat like there is no such thing as an electron being between energy states.

13th July 2009, 06:40 PM	#12
Delvo Illuminator Join Date: Jul 2008 Location: Harrisburg, Pennsylvania Posts: 3,890	Originally Posted by SezMe On a different point, has theoretical physics looked at the possibility that time is quantized? That is, there is no such thing as time between 10e-43 and t=0? Somewhat like there is no such thing as an electron being between energy states. There is no certainty that time is unitized like that, but if it is, then the basic unit's value, the limit beyond which no meaningful calculations or reasoning can be applied, is about 5.4×10^-44. The (rounded off) number "10^-43" is about two of those units. In other words, our calculations only have a chance of being valid and making sense back to the second tick of the universe's clock. The first one is the one giving us the trouble.