A prominent mythological theme is that of time being cyclical. For instance, in Hinduism there is a detailed chronology which repeats endlessly. Bearing in mind that the numbers used in mythological contexts are often mainly there to indicate enormity or tininess, there is the kalpa, which lasts 4 320 million years and is equivalent to a day in Brahma’s life. There are three hundred and sixty of these days in a Brahman year, and a hundred Brahman years in a Brahman lifetime, after which the cycle repeats. Within a Brahman Day, human history also repeats a cycle known as the Yuga Cycle, which consists of four ages, Satya, Treta, Dvapara and Kali. The names refer to the proportion of virtue and vice characterising each age, so Satya is perfect, life is long, everyone is kind to each other, wise, healthy and so on, satya meaning “truth” or “sincerity”, Treta is “third” in the sense of being three quarters virtue and one quarter vice, Dvapara is two quarters of each and Kali, unsurprisingly the current age, is the age of evil and destruction. Humans start off as giants and end as dwarfs. Then the cycle repeats. Thus there are cycles within cycles in Hindu cosmology.
The Maya also have a cyclical chronology, including the Long Count, in a cycle lasting 63 million years. Probably the most important cycle in Mesoamerican calendars is the fifty-two year one, during which the two different calendars cycle in and out of sync with each other. The Aztecs used to give away all their possessions at the end of that period in the expectation that the world might come to an end.
The Jewish tradition has a few similar features as well. Firstly, it appears to use the ages of people to indicate their health and the decline of virtue. The patriarchs named in the Book of Genesis tend to have shorter and shorter lives leading up to the Flood, which ends the lives of the last few generations before it, including the 969-year old Methuselah. Giants are also mentioned in the form of the Nephilim, although they are seen as evil. I wonder if this reflects the inversion of good and evil which took place when Zoroastrianism began, where previously lauded deities were demonised. There is also a cycle in the practice of the Jubilee, consisting of a forty-nine year Golden Jubilee and a shorter seven year Jubilee, and obviously there are the seven-day weeks, which we still have in the West.
The Hindu series of Yugas also reflects the Greek tradition of Golden, Silver, Bronze and Iron Ages, which was ultimately adopted into modern archæology in modified form as the Three-Age System of Stone, Bronze and Iron. The crucial difference between the Hindu and Greek age system and our own ideas of history is that they both believed in steady decline whereas we tend to be more mixed. We tend to believe in progress, although our ideas of what constitutes that do vary quite a lot. In a way, it makes more sense to suppose that everything will get worse, although since history is meant to be cyclical it can also be expected to get better, because of the operation of entropy. Things age, wear out, run down, burn out and so on, and this is the regular experience for everyone, no matter when they’re living in history, and it makes sense that the world might be going in the same direction. On the longest timescale of course it is, because the Sun will burn out, followed by all other stars and so on.
Twentieth century cosmology included a similar theory, that of the oscillating Universe. It was considered possible that the quantity of mass in the Universe was sufficient that once it got past a certain age, gravity acting between all the masses in existence would start to pull everything back together again until it collapsed into the same hot, dense state which started the Universe in the first place. There then emerge a couple of issues. Would the Universe then bounce back and be reborn, only to do it again in an endless cycle? If each cycle is an exact repetition, does it even mean anything to say it’s a different Universe, or is it just the same Universe with time passing in a loop?
This is not currently a popular idea because it turns out that there isn’t enough mass in the Universe to cause it to collapse against the Dark Energy which is pushing everything apart, so ultimately the objects in the Universe are expected to become increasingly isolated until there is only one galaxy visible in each region of the Universe where space is expanding relatively more slowly than the speed of light. This has a significant consequence. A species living in a galaxy at that time would be unaware that things had ever been different. There would be no evidence available to suggest that it was because we can currently see the galaxies receding, and therefore we can know that things will be like that one day, but they would have no way to discover that they hadn’t always been like this. This raises the question of what we might have lost. We reconstruct the history of the Universe based on the data available to us, and we’re aware that we’re surrounded by galaxies which, on the very large scale, are receding from each other, so we can imagine the film rewinding and all the stars and galaxies, or what will become them, starting off in the same place. But at that time, how do we know there wasn’t evidence of something we can no longer recover which is crucial to our own understanding of the Universe?
Physics has been in a bit of a strange state in recent decades. Because the levels of energy required cannot be achieved using current technology, the likes of the Large Hadron Collider are not powerful enough to provide more than a glimpse of the fundamental nature of physical reality. Consequently, physicists are having to engage in guesswork without much feedback, and this applies also to their conception of the entire Universe. I’ve long been very suspicious about the very existence of non-baryonic dark matter. Dark matter was originally proposed as a way to explain why galaxies rotate as if they have much more gravity than their visible matter, i.e. stars, is exerting. In fact, if gravity operates over a long range in the same way as it does over short distances, such as within this solar system or between binary stars, something like nine-tenths of the mass is invisible. To some extent this can be explained by ordinary matter such as dust, planets or very dim stars, and there are also known subatomic particles such as the neutrinos which are very common but virtually undetectable. The issue I have with non-baryonic dark matter, and I’ve been into this before on here, is that it seems to be a specially invented kind of matter to fill the gap in the model which, however, is practically undetectable. There’s another possible solution. What makes this worse is that dark matter is now being used to argue for flaws in the general theory of relativity, when it seems very clear that the problem is actually that physicists have proposed the existence of a kind of substance which is basically magic.
If you go back to the first moment of the Universe, there is a similar issue. Just after the grand unification epoch, a sextillionth (long scale) of a second after the Big Bang, an event is supposed to have taken place which increased each of the three extensive dimensions of the Universe by a factor of the order of one hundred quintillion in a millionth of a yoctosecond. If you don’t recognise these words, the reason is that these are unusually large and small quantities, so their values aren’t that important. Some physicists think this is fishy, because again something seems to have been simply invented to account for what happened in those circumstances without there being other reasons for supposing it to be so. They therefore decided to see what would happen if they used established principles to recreate the early Universe, and in particular they focussed on CPT symmetry
CPT symmetry is Charge, Parity and Temporal symmetry, and can be explained thus, starting with time. Imagine a video of two billiard balls hitting and bouncing off each other out of context. It would be difficult to tell whether that video was being played forwards or backwards. This works well on a small scale, perhaps with two neutrons colliding at about the speed of sound at an angle to each other, or a laser beam reflecting off a mirror. Charge symmetry means that if you observe two equally positively and negatively charged objects interacting, you could swap the charges and still observe the same thing, or for that matter two objects with the same charge could have the opposite charges and still do the same thing. Finally, parity symmetry is the fact that you can’t tell whether what you’re seeing is the right way up or upside down, or reflected. All of these things don’t work in the complicated situations we tend to observe because of pesky things like gravity and accidentally burning things out by sticking batteries in the wrong way round or miswiring plugs, but in sufficiently simple situations all of these things are symmetrical.
But there is a problem. The Universe as a whole doesn’t seem to obey these laws of symmetry. For instance, almost everything we come across seems to be made of matter even though there doesn’t seem to be any reason why there should be more matter than antimatter or the other way round, and time tends to go forwards rather than backwards on the whole. One attempt to explain why matter seems to dominate the Universe is that for some reason in the early Universe more matter was created than antimatter, and since matter meeting antimatter annihilates both, matter is all that’s left. Of course antimatter does crop up from time to time, for instance in bananas and thunderstorms, but it doesn’t last long because it pretty soon comes across an antiparticle in the form of, say, an electron, and the two wipe each other off the map in a burst of energy.
These physicists proposed a solution which does respect this symmetry and allows time to move both forwards and backwards. They propose that the Big Bang created not one but two universes, one where time runs forwards and mainly made of matter and the other where time goes backwards and is mainly made of antimatter, and also either of these universes is geometrically speaking a reflection of the other, such as all the left-handed people in one being right-handed in the other. This explains away the supposèd excess of matter. There’s actually just as much antimatter as matter, but it swapped over at the Big Bang. Before the Big Bang, time was running backwards and the Universe was collapsing.
In a manner rather similar to the thought that an oscillating Universe could be practically the same as time running in a circle because each cycle might be identical and there’s no outside to see it from, the reversed, mirror image antimatter Universe is simply this one running backwards with, again, nothing on the outside to observe it with, and therefore for all intents and purposes there just is this one Universe running forwards after the Big Bang, because it’s indistinguishable from the antimatter one running backwards. On the other hand, the time dimension involved is the same as this one, and therefore it could just be seen as the distant past, which answers the question of what there was before the Big Bang: there was another universe, or rather there was this universe. It also means everything has already happened.
But a further question arises in my head too, and this is by no means what these physicists are claiming. As mentioned above, one model of the Universe is that it repeats itself in a cycle. What we may have here is theoretical support for the idea of a Universe collapsing in on itself before expanding again. That’s the bit we can see or deduce given currently available evidence. However, in the future, certain evidence will be lost because there will only be one visible galaxy observable, and the idea of space expanding will be impossible to support even though it is. What if one of the bits of evidence we’ve already lost is of time looping? Or, what if time just does loop anyway? What if time runs forwards until the Universe reaches a maximum size and then runs backwards again as it contracts? There is an issue with this. There isn’t enough mass in the Universe for it to collapse given the strength of dark energy pushing it apart, but of course elsewhere in the Multiverse there could be looping universes due to different physical constants such as the strength of dark energy or the increased quantity of matter in them, because in fact as has been mentioned before there are possible worlds where this does take place. Another question then arises: how does time work between universes? Are these looping universes doing so now in endless cycles, or are they repeating the same stretch of time? Does time even work that way in the Multiverse, or is it like in Narnia, where time runs at different speeds relative to our world?
It may seem like I’ve become highly speculative. In my defence, I’d say this. I have taken pains to ignore my intuition in the past because I believed it was misleading. However, there appears to be an intuition among many cultures that time does run in a cycle, and the numbers these cultures produce are oddly similar. The Mayan calendar’s longest time period is the Alautun, which lasts 63 081 429 years, close to the number of years it’s been since the Chicxulub Impact, which coincidentally was nearby and wiped out the non-avian dinosaurs. The Indian kalpa is 4 320 million years in length, which is again quite close to the age of this planet. Earth is 4 543 million years old and the Cretaceous ended 66 million years ago, so these figures are 4.6% out in the case of the Maya and 5% for the kalpa. Of course it may be coincidence, and the idea of time being cyclical may simply be based on something like the cycle of the day and night or the seasons through the year, but since I believe intuitive truths are available in Torah and the rest of the Tanakh, I don’t necessarily have a problem with other sources. Parallels have of course been made between ancient philosophies and today’s physics before, for example by Fritjof Capra in his ‘The Tao [sic] Of Physics’. Although much of what he says has been rubbished by physicists since, there is a statue of Dancing Shiva in the lobby at CERN and one quote from Capra is widely accepted:
“Science does not need mysticism and mysticism does not need science. But man needs both.”
A Box Of Chocolates 