Calculations show that everything we see today, from atoms to galaxies,
exists because just one extra particle of matter survived for every billion
matter–antimatter pairs.
Everything about the Universe boggles the mind, but I was unaware of this.
Huh... considering such annihilations should have left nothing but energy behind, from our standpoint, how could we distinguish which of these sequences of events actually happened?
* The early universe produced slightly more matter than antimatter, and they annihilated until matter and energy remained.
* The early universe produced overwhelmingly normal matter and energy, and almost no antimatter.
If you put a lot of energy into a small place, you end up producing particles. We know this and in fact we can do it in particle accelerators. We understand how this happens with a very high degree of precision. The big bang was, essentially, just a huge amount of energy in a tiny place. So according to everything we know about particle physics, lots and lots of matter-antimatter pairs should have been produced. We also know there are some tiny violations of matter-antimatter symmetry that might have caused only one kind to remain after things spread out and cooled down. We know this because we have observed the weak nuclear force violate that symmetry in experiments. But these violations are so tiny that it seems a truly ridiculous amount of matter was necessary in the first place. The only assumption here is that what we currently know about particle physics and quantum field theory still holds true somewhat close to the big bang. I understand that this might seem unsatisfactory on many levels (and it still is to many physicists), but assuming that only one kind of matter was created in the big bang would require a completely new mechanism beyond any currently known physics.
The proportion of matter and anti-matter depends on the temperature.
With increasing temperature, the thresholds of generation for various particle-antiparticle pairs are exceeded, so those kinds of particles and antiparticles are generated in collisions and become a component of the matter of that temperature.
At very high temperatures, matter is composed of almost equal quantities of particles and antiparticles, of a very large number of kinds.
With cooling, some particle-antiparticle pairs are no longer generated and the existing are annihilated, so they cease to be a component of matter.
When the temperature diminishes to a few tens of MeV, then the only particle-antiparticle pairs that remain are of electrons and positrons, while the rest of the matter consists only of free protons, free neutrons, photons and various kinds of neutrinos.
With further cooling, protons and neutrons begin to bind into nuclei, i.e. nuclei of isotopes of hydrogen, helium and lithium.
Then, with even further cooling, the temperature becomes insufficient for generating positrons, so the huge number of existing electrons and positrons annihilate with each other, leaving a much smaller number of electrons, which is equal to the number of protons (free or bound in nuclei of deuterium, He isotopes and Li isotopes), and the amount of charged antiparticles becomes negligible.
At the stage when the temperature is a few tens of MeV and the variety of the particles composing matter is minimal, any memory of what may have happened at other temperatures is erased.
Thus, we cannot extrapolate the Big Bang towards higher temperatures, because there is no evidence of what may have happened before, e.g. of whether higher temperatures have ever existed. The existing evidence could also be matched by a cooler earlier Universe, which has been heated somehow up to a temperature of a few tens of MeV, decomposing any previous matter.
Our astronomical data is consistent with the visible Universe starting at a temperature of a few tens of MeV and high concentration, then cooling and expanding from that state, e.g. this explains the observed chemical composition of the celestial objects.
It can be fun to speculate about what may have happened before that, but it must be kept in mind that for now there is no way to verify any theory that attempts to model earlier stages, e.g. there is no way to verify if the Universe had ever been hotter than a few tens of MeV, i.e. if there have ever been any other abundant antiparticles except positrons (and antineutrinos, which remain abundant even at the present low temperatures, but the nature of antineutrinos is not well understood even today, as anything else that are named antiparticles participate in electromagnetic generation/annihilation reactions with their particle correspondent, while the exact differences between neutrinos and antineutrinos are not clear).
You're basically entering cyclical universe model levels of speculation at this point, which is even wilder. Because you only delay the production of the original matter that seeded "our" universe to a point earlier in time. But given everything we know about particle physics today, it seems at least weird that matter-antimatter is such a well preserved symmetry on small scales and so little on large scales. But if the LHC or future colliders found a highly CP violating process (cough SUSY cough) just above the energy scales we can access right now, everything would fall into place pretty neatly.
The Universe seems vast, unimaginably immense for our meat minds to really grasp, and yet I can't shake the feeling that the Big Bang could have been an insignificant leftover of some even vaster phenomena.
As a former non-atheist, with plenty of people I know in the church that stubbornly refuse to acknowledge accepted science - I've long experimented with theologies in my head to fit the concept of God as they understand it into a cosmological model. Stuff like this is fun for me to point to. Maybe a watchmaker (set it in motion and then stepped away) "god" tipped the scales ever so slightly here (to be clear, I don't believe this, but communicating science to religious people can help to frame things in this way). To me this creates a much more powerful deity than some guy who somehow only created the universe 6,000 years ago but also for some insane reason made it look billions of years old.
Fitting the concept of god into a cosmological model is rather easy.
If we agree that everything we see is described by physics, then everything including us is simply a computation. And in principle someone can build a machine to carry out such a computation.
People in such a machine will be more or less like us, and the creator of that machine will be exactly like god, outside of space and time, omnipotent, omniscient but having to run the simulation to see what everyone does.
From this point of view creating universe 6000 years ago and making it look billions of years old does not look that insane, just a workaround for finite machine time.
So the main disagreement is not about existence of god, or materialism vs idealism, but whether a human is equivalent to a computation or not.
Alternately, an individual set things in motion that they couldn’t control or stop, and thus the universe was born. God could just be a random entity that got in over their proverbial head. We think creating a universe requires thought or intention but it could be a big mistake.
Why did that almighty watchmaker create anti matter in the first place that anihilates the normal matter? They could have just created the normal matter and zero anti matter. Why carefully fine tune these number?
All of these situations are quite convoluted if you want to fit a designer in there.
As a fun aside, have you heard of Nominative Determinism? From a purely rational standpoint, it is mere coincidence that I know a dentist with the last name “Pullum” and an electrician with the last name “Cable”. My confirmation bias doesn’t account for the 99.9% of other people with unremarkable names.
But then I realized… whenever I create fake people for unit tests I give them names that correspond to what they do. Could this be a sign that the universe is a simulation? And, that God is just a QA running some tests on it?
Overarching intellectual models exist for the sake of the problems they solve, rather than to stake claims of supremacy over all other models. Religious-style thinking has important meaning in certain contexts, especially crises and periods of apparent helplessness. Scientific rationalism is useful for solving certain classes of problems in certain ways. To posit universality to either betrays a medieval relationship to thought, not that the person, whether religious or scientific, may be close to succeeding at their position’s impossible sense of their own centrality.
The article didn't say, but a soliton is a solution to a nonlinear PDE that keeps its shape while traveling. One real-world example is a tall ocean wave.
Indeed! I rather like the idea that solitons are something like the simplest self-propagating 'things' in any medium/computation-reigeme, so gliders in Game-of-Life might qualify and in more complex/subtle systems they can have more complex behaviours as well (like bacteria, or flies? Hehe) Here's a fun example I made in gollygang/Ready (and Houdini) of PDE solitons that spin around with rippling wakes:
I believe so, although the way I usually think about Solitons is like a single packet.. so just one cycle of a wave. Continuous sound could probably be thought of as a continuous stream of solitons (I think ppl call them phonons when it's sound though). I haven't studied PDEs nor solitons in a formal way I just love playing with them. Gray Scott with History and Wave (a formula I contributed to Gollygang/Ready) supports many fascinating soliton behaviours. Here's 25mins of one of the strangest parameter settings I've found:
I had a mathematics professor in college whose specialty was in knots. I naively, and probably too bluntly, asked him how his work fit into the world; a question I have regretted to this day. Anyhoo ... I guess this is where it fits into the "world". If you are interested, here is his Wikipedia page:
The more we learn the more I'm unsure of whether it is a wonder anything exists at all or whether considering the scales of time involved (and hypothetical metaverse) whether it was all inevitable.
You can take it back out even further and ask why a universe in which chemistry is even possible popped up. A single small change and either everything becomes unbelievably heavy and collapses, or everything stays unreasonably light and we never get past hydrogen and helium.
Fun fact: it's very easy to rule out a multiverse theory where travel between universes is possible.
If the multiverse theory is correct, every possible combination of universe is out there. This means there is a universe which formed in exactly the right way such that the citizens all decided to leave their universe and invade our specific one. They formed 10 billion years ago and completely annihilated all matter in our universe.
Since we are still here, either the multiverse is false, or travel between universes is impossible.
You're assuming that that particular set of universes is possible. Maybe it hasn't happened because getting them to agree is not scientifically possible.
This reminds me of Stephen Hawking telling John Oliver that the latter dating Charlize Theron is beyond the bounds of scientific possibility in any of the infinite parallel universes.
If you define "our" universe as a particular set of states aren't there more than one of "ours" or in fact an infinite number of them which are either identical or indistinguishable some of which got invaded and more which didn't?
Only the ones in which we all didn't get murdered are having this conversation.
In 1867, Lord Kelvin imagined atoms as knots in the aether.
I had never heard of this before, and I find the idea absolutely delightful. As I understand it, the "knots" are stable vortices in the aether. It was popular from 1870 - 1890, and it blows my mind that only a few years later the electron was discovered (1897), and less than 50 years later (1938), the scanning electron microscope was invented! 1955 was when the atom was first imaged.
It's interesting that the mathematical theory of knots was initially developed in response to Kelvin's proposal (i.e. Tait's work), because people were motivated trying to work out its implications for atomic theory. A branch of mathematics created by wrong physics.
I think the idea of knots as a basis for everything has come and gone several times. One of those were in the 90s, which is when I became aware thanks to the excellent "Gauge Fields, Knots and Gravity" by John Baez and Javier P Muniain, that was part of the "Series on Knots and Everything" [1]. Those are really intriguing ideas.
My personal theory is that universes are born from black holes (or rather, the exit end of the black hole). There are more than one such universe. Big bang theory isn't exactly correct -- our universe expanded from the tail end of a collapsing black hole. I think various "universes" share the same overall laws of physics, but can have different arrangements. Knots certainly fits in this and could explain some of the things.
I think the title removed the wrong words to make it fit into 80 characters. The actual title is “The key to why the universe exists may lie in an 1800s knot idea science once dismissed”. Removing “why the” makes the title ungrammatical. Removing just “science once dismissed” from the end would work better.
I agree that that would be a good way to shorten it, but the title itself needs to be changed ("Please use the original title, unless it is misleading or linkbait" - https://news.ycombinator.com/newsguidelines.html). "Key to why the universe exists" is linkbaity, and "1800s knot idea" appears misleading, since the intersection between what Kelvin said and what these researchers are saying appears to be just "knots".
Edit: The mention of Kelvin's original idea does make the article more interesting though!
Huh... considering such annihilations should have left nothing but energy behind, from our standpoint, how could we distinguish which of these sequences of events actually happened?
* The early universe produced slightly more matter than antimatter, and they annihilated until matter and energy remained.
* The early universe produced overwhelmingly normal matter and energy, and almost no antimatter.
If you put a lot of energy into a small place, you end up producing particles. We know this and in fact we can do it in particle accelerators. We understand how this happens with a very high degree of precision. The big bang was, essentially, just a huge amount of energy in a tiny place. So according to everything we know about particle physics, lots and lots of matter-antimatter pairs should have been produced. We also know there are some tiny violations of matter-antimatter symmetry that might have caused only one kind to remain after things spread out and cooled down. We know this because we have observed the weak nuclear force violate that symmetry in experiments. But these violations are so tiny that it seems a truly ridiculous amount of matter was necessary in the first place. The only assumption here is that what we currently know about particle physics and quantum field theory still holds true somewhat close to the big bang. I understand that this might seem unsatisfactory on many levels (and it still is to many physicists), but assuming that only one kind of matter was created in the big bang would require a completely new mechanism beyond any currently known physics.
The proportion of matter and anti-matter depends on the temperature.
With increasing temperature, the thresholds of generation for various particle-antiparticle pairs are exceeded, so those kinds of particles and antiparticles are generated in collisions and become a component of the matter of that temperature.
At very high temperatures, matter is composed of almost equal quantities of particles and antiparticles, of a very large number of kinds.
With cooling, some particle-antiparticle pairs are no longer generated and the existing are annihilated, so they cease to be a component of matter.
When the temperature diminishes to a few tens of MeV, then the only particle-antiparticle pairs that remain are of electrons and positrons, while the rest of the matter consists only of free protons, free neutrons, photons and various kinds of neutrinos.
With further cooling, protons and neutrons begin to bind into nuclei, i.e. nuclei of isotopes of hydrogen, helium and lithium.
Then, with even further cooling, the temperature becomes insufficient for generating positrons, so the huge number of existing electrons and positrons annihilate with each other, leaving a much smaller number of electrons, which is equal to the number of protons (free or bound in nuclei of deuterium, He isotopes and Li isotopes), and the amount of charged antiparticles becomes negligible.
At the stage when the temperature is a few tens of MeV and the variety of the particles composing matter is minimal, any memory of what may have happened at other temperatures is erased.
Thus, we cannot extrapolate the Big Bang towards higher temperatures, because there is no evidence of what may have happened before, e.g. of whether higher temperatures have ever existed. The existing evidence could also be matched by a cooler earlier Universe, which has been heated somehow up to a temperature of a few tens of MeV, decomposing any previous matter.
Our astronomical data is consistent with the visible Universe starting at a temperature of a few tens of MeV and high concentration, then cooling and expanding from that state, e.g. this explains the observed chemical composition of the celestial objects.
It can be fun to speculate about what may have happened before that, but it must be kept in mind that for now there is no way to verify any theory that attempts to model earlier stages, e.g. there is no way to verify if the Universe had ever been hotter than a few tens of MeV, i.e. if there have ever been any other abundant antiparticles except positrons (and antineutrinos, which remain abundant even at the present low temperatures, but the nature of antineutrinos is not well understood even today, as anything else that are named antiparticles participate in electromagnetic generation/annihilation reactions with their particle correspondent, while the exact differences between neutrinos and antineutrinos are not clear).
You're basically entering cyclical universe model levels of speculation at this point, which is even wilder. Because you only delay the production of the original matter that seeded "our" universe to a point earlier in time. But given everything we know about particle physics today, it seems at least weird that matter-antimatter is such a well preserved symmetry on small scales and so little on large scales. But if the LHC or future colliders found a highly CP violating process (cough SUSY cough) just above the energy scales we can access right now, everything would fall into place pretty neatly.
The Universe seems vast, unimaginably immense for our meat minds to really grasp, and yet I can't shake the feeling that the Big Bang could have been an insignificant leftover of some even vaster phenomena.
As a former non-atheist, with plenty of people I know in the church that stubbornly refuse to acknowledge accepted science - I've long experimented with theologies in my head to fit the concept of God as they understand it into a cosmological model. Stuff like this is fun for me to point to. Maybe a watchmaker (set it in motion and then stepped away) "god" tipped the scales ever so slightly here (to be clear, I don't believe this, but communicating science to religious people can help to frame things in this way). To me this creates a much more powerful deity than some guy who somehow only created the universe 6,000 years ago but also for some insane reason made it look billions of years old.
Fitting the concept of god into a cosmological model is rather easy.
If we agree that everything we see is described by physics, then everything including us is simply a computation. And in principle someone can build a machine to carry out such a computation.
People in such a machine will be more or less like us, and the creator of that machine will be exactly like god, outside of space and time, omnipotent, omniscient but having to run the simulation to see what everyone does.
From this point of view creating universe 6000 years ago and making it look billions of years old does not look that insane, just a workaround for finite machine time.
So the main disagreement is not about existence of god, or materialism vs idealism, but whether a human is equivalent to a computation or not.
Alternately, an individual set things in motion that they couldn’t control or stop, and thus the universe was born. God could just be a random entity that got in over their proverbial head. We think creating a universe requires thought or intention but it could be a big mistake.
But was it a mistake born out of a mistake?
Fitting the concept of god into any scheme is easy, because the existence of god isn't falsifiable.
Why did that almighty watchmaker create anti matter in the first place that anihilates the normal matter? They could have just created the normal matter and zero anti matter. Why carefully fine tune these number?
All of these situations are quite convoluted if you want to fit a designer in there.
As a fun aside, have you heard of Nominative Determinism? From a purely rational standpoint, it is mere coincidence that I know a dentist with the last name “Pullum” and an electrician with the last name “Cable”. My confirmation bias doesn’t account for the 99.9% of other people with unremarkable names.
But then I realized… whenever I create fake people for unit tests I give them names that correspond to what they do. Could this be a sign that the universe is a simulation? And, that God is just a QA running some tests on it?
So maybe we’re living in an edge case!
https://en.wikipedia.org/wiki/Nominative_determinism
Maybe it “looked away” to give its creation a bit of free will unconstrained by its own awesome deterministic power.
Overarching intellectual models exist for the sake of the problems they solve, rather than to stake claims of supremacy over all other models. Religious-style thinking has important meaning in certain contexts, especially crises and periods of apparent helplessness. Scientific rationalism is useful for solving certain classes of problems in certain ways. To posit universality to either betrays a medieval relationship to thought, not that the person, whether religious or scientific, may be close to succeeding at their position’s impossible sense of their own centrality.
The article didn't say, but a soliton is a solution to a nonlinear PDE that keeps its shape while traveling. One real-world example is a tall ocean wave.
Indeed! I rather like the idea that solitons are something like the simplest self-propagating 'things' in any medium/computation-reigeme, so gliders in Game-of-Life might qualify and in more complex/subtle systems they can have more complex behaviours as well (like bacteria, or flies? Hehe) Here's a fun example I made in gollygang/Ready (and Houdini) of PDE solitons that spin around with rippling wakes:
https://youtu.be/edNG2EJWQwQ?si=8b3YsHCDIaj0C7Pa
Wow! I'd never heard of gollygang/ready before, but it looks extremely cool. Thanks for sharing.
No probs, I've had a great deal of fun playing with it indeed! Hope you do too!
Would sound waves then count as solitons?
I believe so, although the way I usually think about Solitons is like a single packet.. so just one cycle of a wave. Continuous sound could probably be thought of as a continuous stream of solitons (I think ppl call them phonons when it's sound though). I haven't studied PDEs nor solitons in a formal way I just love playing with them. Gray Scott with History and Wave (a formula I contributed to Gollygang/Ready) supports many fascinating soliton behaviours. Here's 25mins of one of the strangest parameter settings I've found:
https://youtu.be/Naj_J8aznyk?si=Da3A3iTz8rN9qrgq
I had a mathematics professor in college whose specialty was in knots. I naively, and probably too bluntly, asked him how his work fit into the world; a question I have regretted to this day. Anyhoo ... I guess this is where it fits into the "world". If you are interested, here is his Wikipedia page:
https://en.wikipedia.org/wiki/Morwen_Thistlethwaite
The more we learn the more I'm unsure of whether it is a wonder anything exists at all or whether considering the scales of time involved (and hypothetical metaverse) whether it was all inevitable.
You can take it back out even further and ask why a universe in which chemistry is even possible popped up. A single small change and either everything becomes unbelievably heavy and collapses, or everything stays unreasonably light and we never get past hydrogen and helium.
Fun fact: it's very easy to rule out a multiverse theory where travel between universes is possible.
If the multiverse theory is correct, every possible combination of universe is out there. This means there is a universe which formed in exactly the right way such that the citizens all decided to leave their universe and invade our specific one. They formed 10 billion years ago and completely annihilated all matter in our universe.
Since we are still here, either the multiverse is false, or travel between universes is impossible.
You're assuming that that particular set of universes is possible. Maybe it hasn't happened because getting them to agree is not scientifically possible.
This reminds me of Stephen Hawking telling John Oliver that the latter dating Charlize Theron is beyond the bounds of scientific possibility in any of the infinite parallel universes.
That’s not really what ‘infinite’ means.
Wouldn't that be infinite universe theory?
> If the multiverse theory is correct, every possible combination of universe is out there.
Says who? There are an infinite number of real numbers that have only 1s and 0s in their decimal expansion.
If you define "our" universe as a particular set of states aren't there more than one of "ours" or in fact an infinite number of them which are either identical or indistinguishable some of which got invaded and more which didn't?
Only the ones in which we all didn't get murdered are having this conversation.
There'd be infinite universes where that happened and infinite universes where it did not.
In 1867, Lord Kelvin imagined atoms as knots in the aether.
I had never heard of this before, and I find the idea absolutely delightful. As I understand it, the "knots" are stable vortices in the aether. It was popular from 1870 - 1890, and it blows my mind that only a few years later the electron was discovered (1897), and less than 50 years later (1938), the scanning electron microscope was invented! 1955 was when the atom was first imaged.
https://en.wikipedia.org/wiki/Vortex_theory_of_the_atom
I was literally just reading about this (see in particular "arguments in favor of")
https://webhomes.maths.ed.ac.uk/~v1ranick/papers/mfaknot.pdf ("Geometry and Physics of Knots" by Atiyah)
It's interesting that the mathematical theory of knots was initially developed in response to Kelvin's proposal (i.e. Tait's work), because people were motivated trying to work out its implications for atomic theory. A branch of mathematics created by wrong physics.
I think the idea of knots as a basis for everything has come and gone several times. One of those were in the 90s, which is when I became aware thanks to the excellent "Gauge Fields, Knots and Gravity" by John Baez and Javier P Muniain, that was part of the "Series on Knots and Everything" [1]. Those are really intriguing ideas.
[1] https://www.worldscientific.com/series/skae
Oddly close to to the QFT view while missing the fundamental nature of fields.
My personal theory is that universes are born from black holes (or rather, the exit end of the black hole). There are more than one such universe. Big bang theory isn't exactly correct -- our universe expanded from the tail end of a collapsing black hole. I think various "universes" share the same overall laws of physics, but can have different arrangements. Knots certainly fits in this and could explain some of the things.
I think the title removed the wrong words to make it fit into 80 characters. The actual title is “The key to why the universe exists may lie in an 1800s knot idea science once dismissed”. Removing “why the” makes the title ungrammatical. Removing just “science once dismissed” from the end would work better.
The article's title is too baity for HN so I lifted a phrase from the paper itself. More at https://news.ycombinator.com/item?id=45696368
For convenience @dang, the new suggested title is
The key to why the universe exists may lie in an 1800s knot idea
When I first read the existing title I was also very confused
I agree that that would be a good way to shorten it, but the title itself needs to be changed ("Please use the original title, unless it is misleading or linkbait" - https://news.ycombinator.com/newsguidelines.html). "Key to why the universe exists" is linkbaity, and "1800s knot idea" appears misleading, since the intersection between what Kelvin said and what these researchers are saying appears to be just "knots".
Edit: The mention of Kelvin's original idea does make the article more interesting though!
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