<p>Yes there are. They are mainly based on what dominates the energy density of the universe at the time and they are known as epochs.</p>
<p>Thus we have the inflationary epoch in the first tiny fraction (<span class="math-container">$\sim 10^{-32}$</span>) of a second, when the energy density was dominated by an inflationary field.</p>
<p>Then we are in the electroweak epoch, when the weak nuclear and electromagnetic forces were united.</p>
<p>This is followed by the quark epoch when the electromagnetic and weak nuclear forces separate at about <span class="math-container">$10^{-12}$</span>s, which is followed by the hadron epoch between about a millionth of a second and 1 second, when quarks were able to be confined into multi-quark hadrons.</p>
<p>Then the lepton epoch between about 1 second and a minute when most of the hadrons have annihilated with each other and the energy density is dominated by electrons, positrons and neutrinos, although this also coincides with the &quot;epoch of primordial nucleosynthesis&quot; when the first multi-nucleon nuclei were built.</p>
<p>From there until about 300,000 years, we have the radiation epoch, when photons dominated the energy density of the universe.</p>
<p>After that, the universe entered the matter-dominated epoch for about 5 billion years and now we are in the epoch where the universe is dominated by dark energy.</p>
<p>There are other schemes and other nomenclatures depending on what physics is being focused on. For example, people interested in the formation of the first stars will talk about the &quot;epoch of reionization&quot;, which occurred some 100 million years after the big-bang. Those studying the cosmic microwave background talk about the &quot;epoch of recombination&quot;, which coincides roughly with the transition from a radiation to a matter-dominated universe.</p>

CC BY-SA 4.0
2021-01-25T16:13:35.910Z
Of course, it's a little bit hard to describe the early universe in terms of "seconds" or "fractions of seconds", since the flow of time depends on the expansion of space, and with all of space and matter compressed into a singularity at the moment of the Big Bang, time is basically infinite.  Or at least it's sort of nonsensical to even ask "What was there before the Big Bang?" since time itself can only be defined in terms of space-time expansion.  (I'm probably mangling this a bit - is there an astrophysicist in the house?)
Darrel Hoffman
CC BY-SA 4.0
2021-01-25T16:26:13.050Z
@DarrelHoffman Not sure what you are getting at. My usage of time (in seconds) is perfectly standard in cosmology. There is no discussion in my answer of time before the big bang.
ProfRob
CC BY-SA 4.0
2021-01-25T16:30:27.173Z
Right, it's just that time as you get close to the big bang (from this side) cannot be as easily measured using familiar terminology.  The math kind of breaks down the closer you get to singularity.  I'm not good at explaining it, I've just watched a lot of educational stuff on this, though it might just be one of those "different schools of thought" issues.
Darrel Hoffman
CC BY-SA 4.0
2021-01-25T17:34:23.557Z
@DarrelHoffman It is the proper time measured since  the scale factor was zero in a standard $\Lambda$CDM cosmology. See https://en.wikipedia.org/wiki/Cosmic_time . If you are talking about the possibility that anything could have happened prior to inflation then sure - that's why I started at that point.
ProfRob
CC BY-SA 4.0
2021-01-25T17:40:17.440Z
One solution to this is to use Plank, or natural units rather than seconds. Since one unit of time on the Plank units is 10^−44 seconds,  you get Inflation for the first trillion plank units, then the electroweak epoch ends at 10^32 and so on.  Of course **this doesn't change anything**, it just replaces unimaginably small fractions of a second with unimaginably huge multiples of Plank time.  But by using Plank units, you see that "inflation" was not a very short period of time, it's just that the rest of the history of the universe is unimaginably long.
James K
CC BY-SA 4.0
2021-01-25T17:59:42.397Z
@James They're Planck units. ;) The Wikipedia Big Bang graphical timeline nicely deals with the time "compression" issue by using logarithmic time.
PM 2Ring
CC BY-SA 4.0
2021-01-25T07:42:13.293Z
2021-01-25T16:29:17.247Z
2021-01-25T16:29:17.247Z
ProfRob
<p><a href="https://www.infoplease.com/math-science/earth-environment/table-of-geological-periods" rel="noreferrer">Geological periods</a> describe varying phases in the last few hundred million years on earth.</p>
<p>Are there any names for the periods on a timescale 1-2 orders of magnitude greater, that is, for the stages of a/the universe?</p>
<p>I found some bits and <a href="https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe" rel="noreferrer">pieces of information</a> but nothing as clear as I did for geological periods, possibly because of the conjecture involved.</p>

CC BY-SA 4.0
2021-01-25T05:01:54.490Z
There's also https://en.wikipedia.org/wiki/Graphical_timeline_of_the_Big_Bang for the early times.
PM 2Ring
CC BY-SA 4.0
2021-01-25T05:06:28.853Z
@PM2Ring extremely useful. I think that's all the stages in the first ~100m years of the universe from the big bang. I found [this](https://en.wikipedia.org/wiki/Graphical_timeline_from_Big_Bang_to_Heat_Death) on that page as well which speculatively shows periods beyond 100m years
stevec
CC BY-SA 4.0
2021-01-25T07:15:51.520Z
You have to know that the universe started very rapidly and made a lot of changes in the first second or so. Geology isn't so inequal. Of course Quaternary is shorter than Cambrian, for example, but these inequalities aren't so obvious. The line between geology and cosmology is nearly impossible to make. By the way, humans have developed three main points of the universe: start, now (Earth ...) and end. The periods are shorter and more detailed near these three points. But between them? There are just some long periods where almost nothing happens.
User123
CC BY-SA 4.0
2021-01-25T16:02:08.450Z
https://en.wikipedia.org/wiki/Chronology_of_the_universe
Barmar
CC BY-SA 4.0
2021-01-25T23:40:59.230Z
@User123 "...where almost nothing happens", *that we know of*. I'm sure there were plenty of planet destroying collisions, galaxy merging mayhem, and enough supernova to make those long periods quite interesting, if we can figure it out.
TCooper
CC BY-SA 4.0
2021-01-26T08:48:02.563Z
@MetinCelik In case your answer gets deleted as "link-only answer", here your link https://www.youtube.com/watch?v=uD4izuDMUQA
B--rian
CC BY-SA 4.0
2021-01-26T08:56:18.777Z
@B--rian good idea. Here is my comment from MetinCelik's answer: How farcically wrong I was to assume the universe's life would be "1-2 orders of magnitude greater (than the last few hundred million years)". According to [Brian Cox](https://www.youtube.com/watch?v=uD4izuDMUQA#t=13m15s): "as a fraction of the lifespan of the universe ... life as we know it is only possible for 1 thousandth of a billionth billionth billionth billionth billionth billionth billionth billionth billionth of a percent"
stevec
CC BY-SA 4.0
2021-01-26T10:52:22.373Z
@TCooper If there was no human, there would be just two main points: start (the universe and matter is made) and end (the hypothetical death of the universe). The most important things here are on the scale of the whole universe. But because there are humans, we made additional periods, specific to some random planet, called Earth (just because we are here). But collisions of galaxies and planets have nothing to do with stages in the life of a universe. They are too minor and unimportant. As I mentioned, the only exception is the Earth because it is special and we live on it.
User123
CC BY-SA 4.0
2021-01-26T18:13:11.423Z
@User123 That's the most narcissistic(as a species) viewpoint I've ever heard. To say that our living on this planet is more relevant to the life of the universe than the collision of entire galaxies inside of it... maybe I'm misunderstanding you? I won't arguing your point that the events I mentioned are trivial, but they're far more relevant to the life of a universe than the human species is. Just because we're the ones describing it, doesn't mean we need to make it entirely relative to ourselves.
TCooper
CC BY-SA 4.0
2021-01-26T18:55:56.240Z
@TCooper But these periods that are based at the idea of the Earth are geological or historical. We have them because they are more relevant to us than some exoplanets. We have to know when did the dinosaurs extinct, but we don't have to know that some exoplanet just collided with his moon. It is not narcissistic, it's just us. Take that analogy: how good do you know yourself and how good do you know some random guy. Is your knowledge about yourself narcissistic? Should you meet some random guy and forget most things about yourself? No, it is just you.
User123
CC BY-SA 4.0
2021-01-26T18:59:14.833Z
@Tcooper You have to note that galaxy collision isn't such dramatic event. There aren't some flashes - just new galaxy is made. But to make a period out of it? No. There are a lot of galaxies present in the universe. By the way, some extraterrestrial inteligence would prefer our planet for exploration in front of some random hot jupiter. Our planet is just special :)
User123
CC BY-SA 4.0
2021-01-26T19:46:49.610Z
@User123 describing the life of a universe from our perspective is far different than, and I'd argue inferior to, describing the life of a universe objectively. To use your analogy, if I were asked to describe the whole of two people, myself and a stranger, and I only provided the details of myself as a purported description of us both, that's very narcissistic. Absence of knowledge doesn't justify willingly excluding it in an answer.
TCooper
CC BY-SA 4.0
2021-01-26T19:54:21.117Z
@TCooper I think that we're not here at the same point. You argue that we are very narcissistic because we defined the geological and historical periods just for the Earth. But which geological or even historical periods would you put down for some random exoplanet? We don't know much about them. What about the planets in the Solar system? Even there we don't know much about their geology. First of all, there are Jovian planets that we're not interested in. Mercury is too far and pretty hot to explore. Even worse with Venus. Only Mars is left, but we don't have enough data to make conclusions.
User123
CC BY-SA 4.0
2021-01-27T00:54:53.700Z
@User123 I've said nothing about anything on earth, as I think it's entirely irrelevant to discussing the life of a universe in a practical manner ;)
TCooper
CC BY-SA 4.0
2021-01-27T07:15:41.930Z
Ok, let's stop with this argumenting. If you think that you are right, I'm fine. But I think that this conversation was entirely unuseful. Everything started when I wrote that in these periods almost nothing happens-I meant relevant to the universe. We added some periods around the present because we live here and Earth is very relevant to us. Also you haven't argumented your point of view or your arguments are false. For example, galaxies are very small at the scale of the universe but you give them very large meaning. Another analogy: let's make periods when the bubbles on the ocean collide!
User123
<universe><space-time><time>
What are the stages in the life of a universe?
stevec
# What are the stages in the life of a universe?

(Asked by: username_0 on 2021-01-25)

[Geological periods](https://www.infoplease.com/math-science/earth-environment/table-of-geological-periods) describe varying phases in the last few hundred million years on earth.

Are there any names for the periods on a timescale 1-2 orders of magnitude greater, that is, for the stages of a/the universe?

I found some bits and [pieces of information](https://en.wikipedia.org/wiki/Ultimate_fate_of_the_universe) but nothing as clear as I did for geological periods, possibly because of the conjecture involved.

**Tags:** universe, space-time, time
> **Comments:**
> **username_1**: There's also https://en.wikipedia.org/wiki/Graphical_timeline_of_the_Big_Bang for the early times.  
> **username_0**: @PM2Ring extremely useful. I think that's all the stages in the first ~100m years of the universe from the big bang. I found [this](https://en.wikipedia.org/wiki/Graphical_timeline_from_Big_Bang_to_Heat_Death) on that page as well which speculatively shows periods beyond 100m years  
> **username_2**: You have to know that the universe started very rapidly and made a lot of changes in the first second or so. Geology isn't so inequal. Of course Quaternary is shorter than Cambrian, for example, but these inequalities aren't so obvious. The line between geology and cosmology is nearly impossible to make. By the way, humans have developed three main points of the universe: start, now (Earth ...) and end. The periods are shorter and more detailed near these three points. But between them? There are just some long periods where almost nothing happens.  
> **username_3**: https://en.wikipedia.org/wiki/Chronology_of_the_universe  
> **username_4**: @User123 "...where almost nothing happens", *that we know of*. I'm sure there were plenty of planet destroying collisions, galaxy merging mayhem, and enough supernova to make those long periods quite interesting, if we can figure it out.  
> **username_5**: @MetinCelik In case your answer gets deleted as "link-only answer", here your link https://www.youtube.com/watch?v=uD4izuDMUQA  
> **username_0**: @B--rian good idea. Here is my comment from MetinCelik's answer: How farcically wrong I was to assume the universe's life would be "1-2 orders of magnitude greater (than the last few hundred million years)". According to [Brian Cox](https://www.youtube.com/watch?v=uD4izuDMUQA#t=13m15s): "as a fraction of the lifespan of the universe ... life as we know it is only possible for 1 thousandth of a billionth billionth billionth billionth billionth billionth billionth billionth billionth of a percent"  
> **username_2**: @TCooper If there was no human, there would be just two main points: start (the universe and matter is made) and end (the hypothetical death of the universe). The most important things here are on the scale of the whole universe. But because there are humans, we made additional periods, specific to some random planet, called Earth (just because we are here). But collisions of galaxies and planets have nothing to do with stages in the life of a universe. They are too minor and unimportant. As I mentioned, the only exception is the Earth because it is special and we live on it.  
> **username_4**: @User123 That's the most narcissistic(as a species) viewpoint I've ever heard. To say that our living on this planet is more relevant to the life of the universe than the collision of entire galaxies inside of it... maybe I'm misunderstanding you? I won't arguing your point that the events I mentioned are trivial, but they're far more relevant to the life of a universe than the human species is. Just because we're the ones describing it, doesn't mean we need to make it entirely relative to ourselves.  
> **username_2**: @TCooper But these periods that are based at the idea of the Earth are geological or historical. We have them because they are more relevant to us than some exoplanets. We have to know when did the dinosaurs extinct, but we don't have to know that some exoplanet just collided with his moon. It is not narcissistic, it's just us. Take that analogy: how good do you know yourself and how good do you know some random guy. Is your knowledge about yourself narcissistic? Should you meet some random guy and forget most things about yourself? No, it is just you.  
> **username_2**: @Tcooper You have to note that galaxy collision isn't such dramatic event. There aren't some flashes - just new galaxy is made. But to make a period out of it? No. There are a lot of galaxies present in the universe. By the way, some extraterrestrial inteligence would prefer our planet for exploration in front of some random hot jupiter. Our planet is just special :)  
> **username_4**: @User123 describing the life of a universe from our perspective is far different than, and I'd argue inferior to, describing the life of a universe objectively. To use your analogy, if I were asked to describe the whole of two people, myself and a stranger, and I only provided the details of myself as a purported description of us both, that's very narcissistic. Absence of knowledge doesn't justify willingly excluding it in an answer.  
> **username_2**: @TCooper I think that we're not here at the same point. You argue that we are very narcissistic because we defined the geological and historical periods just for the Earth. But which geological or even historical periods would you put down for some random exoplanet? We don't know much about them. What about the planets in the Solar system? Even there we don't know much about their geology. First of all, there are Jovian planets that we're not interested in. Mercury is too far and pretty hot to explore. Even worse with Venus. Only Mars is left, but we don't have enough data to make conclusions.  
> **username_4**: @User123 I've said nothing about anything on earth, as I think it's entirely irrelevant to discussing the life of a universe in a practical manner ;)  
> **username_2**: Ok, let's stop with this argumenting. If you think that you are right, I'm fine. But I think that this conversation was entirely unuseful. Everything started when I wrote that in these periods almost nothing happens-I meant relevant to the universe. We added some periods around the present because we live here and Earth is very relevant to us. Also you haven't argumented your point of view or your arguments are false. For example, galaxies are very small at the scale of the universe but you give them very large meaning. Another analogy: let's make periods when the bubbles on the ocean collide!  

---

## 1 answers

### Answer by username_6 on 2021-01-25. Score: 17

Yes there are. They are mainly based on what dominates the energy density of the universe at the time and they are known as epochs.

Thus we have the inflationary epoch in the first tiny fraction ($\sim 10^{-32}$) of a second, when the energy density was dominated by an inflationary field.

Then we are in the electroweak epoch, when the weak nuclear and electromagnetic forces were united.

This is followed by the quark epoch when the electromagnetic and weak nuclear forces separate at about $10^{-12}$s, which is followed by the hadron epoch between about a millionth of a second and 1 second, when quarks were able to be confined into multi-quark hadrons.

Then the lepton epoch between about 1 second and a minute when most of the hadrons have annihilated with each other and the energy density is dominated by electrons, positrons and neutrinos, although this also coincides with the "epoch of primordial nucleosynthesis" when the first multi-nucleon nuclei were built.

From there until about 300,000 years, we have the radiation epoch, when photons dominated the energy density of the universe.

After that, the universe entered the matter-dominated epoch for about 5 billion years and now we are in the epoch where the universe is dominated by dark energy.

There are other schemes and other nomenclatures depending on what physics is being focused on. For example, people interested in the formation of the first stars will talk about the "epoch of reionization", which occurred some 100 million years after the big-bang. Those studying the cosmic microwave background talk about the "epoch of recombination", which coincides roughly with the transition from a radiation to a matter-dominated universe.

> **Comments:**
> **username_7**: Of course, it's a little bit hard to describe the early universe in terms of "seconds" or "fractions of seconds", since the flow of time depends on the expansion of space, and with all of space and matter compressed into a singularity at the moment of the Big Bang, time is basically infinite.  Or at least it's sort of nonsensical to even ask "What was there before the Big Bang?" since time itself can only be defined in terms of space-time expansion.  (I'm probably mangling this a bit - is there an astrophysicist in the house?)  
> **username_6**: @DarrelHoffman Not sure what you are getting at. My usage of time (in seconds) is perfectly standard in cosmology. There is no discussion in my answer of time before the big bang.  
> **username_7**: Right, it's just that time as you get close to the big bang (from this side) cannot be as easily measured using familiar terminology.  The math kind of breaks down the closer you get to singularity.  I'm not good at explaining it, I've just watched a lot of educational stuff on this, though it might just be one of those "different schools of thought" issues.  
> **username_6**: @DarrelHoffman It is the proper time measured since  the scale factor was zero in a standard $\Lambda$CDM cosmology. See https://en.wikipedia.org/wiki/Cosmic_time . If you are talking about the possibility that anything could have happened prior to inflation then sure - that's why I started at that point.  
> **username_8**: One solution to this is to use Plank, or natural units rather than seconds. Since one unit of time on the Plank units is 10^−44 seconds,  you get Inflation for the first trillion plank units, then the electroweak epoch ends at 10^32 and so on.  Of course **this doesn't change anything**, it just replaces unimaginably small fractions of a second with unimaginably huge multiples of Plank time.  But by using Plank units, you see that "inflation" was not a very short period of time, it's just that the rest of the history of the universe is unimaginably long.  
> **username_1**: @James They're Planck units. ;) The Wikipedia Big Bang graphical timeline nicely deals with the time "compression" issue by using logarithmic time.  

---

