## Space – the Final Front Ear

Sorry about the fabricated mondegreen, which obviously references the Star Trek series of films and TV shows. Captain Kirk saw space, or more correctly distance, as a barrier, but it really is one of the factors that determines the structure or shape of our Universe.

It is interesting to me, that, although the Universe is finite, if it derived from a Big Bang, there is a human urge to explore outwards, as if it were infinite. That is probably one of the factors that led scientists such as Fred Hoyle and others to support a Steady State Theory of the Universe.

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Personally, I believe that there is no such thing as a steady state in anything. When we see something which appears to be in a steady state or equilibrium state we should look for the feedback factors that are keeping it that way. For example a pendulum hangs straight down when at rest because any deviation from that position results in gravitation forces pulling it back to the rest position.

If friction is low the pendulum will actually pass through the equilibrium position and swing to the other side, whereupon gravity will slow it and draw it back towards the equilibrium position again. Eventually friction will slow the pendulum down and the pendulum will again hang vertically.

So we have two forces, gravity and friction, resulting in the pendulum returning to the equilibrium position. No pendulum lasts for ever, as the pivot will wear out or an elephant may step on the thing, so the equilibrium will only exist for a finite time, but it will last long enough for us to use in clocks or in scientific experiments.

Space is itself expanding as I understand the theories and some of it is out of our sight, over an event horizon, which is a locus where everything is moving away from us at the speed of light. That doesn’t much our location special – it is true of any point in the Universe. LGM on a planet around a star that is over the event horizon from us have their own event horizon, and while they may be able to see a star inside our event horizon and we in theirs, we cannot see each other.

Space separates us form the LGM, but it also separates from things local to us. Ben, our dog, is over there, about 3 metres away. My cup is mere centimetres away. It is fair to say, I think, that this is the essence of space – it is hard to conceive a universe which doesn’t incorporate a spacial concept. Or rather, a separation concept to allow things to be different from one another.

Space is not the only “separation concept” that I can think of. Things can also be separated in time, so two different bodies can exist in the same spacial position, but just not at the same time. Time is so connected to space that Einstein and others were able to link time and space into a complex space/time concept.

The similarity between the space dimension and the time dimension is striking. You can even measure distance in time units as astronomers do when they talk about light years. We also do it when we say that a distant town is three hours away.

We less frequently talk of time in distance units, for example, when we say things like “six laps later”, to describe the time between two events in a car race. At some level we acknowledge that time and the space dimension have a lot in common.

Space in the sort of concept that everyone knows and experiences but no one thinks deeply about. There’s no doubt that space separates events from one another. You can’t have two solid objects occupying the same space at the same time, without catastrophe ensuing. Scientists have been trying to achieve this for years, with the aim of harvesting the energy generated from the ensuring nuclear fusion.

Space appears on the macro (normal) level to be continuous. We appear to move smoothly from one location to another when we walk, incidentally forcing the air out of way as we do so. There is no sudden jumps that we notice, we don’t hop from point to point like a chess piece on a board.

The philosopher Zeno came up with a number of paradoxes related to movement, that is getting from point A to point B. For instance, the athlete Achilles could not overtake a tortoise in a foot race, because Achilles would need first to reach the tortoise’s starting point, by which time the tortoise would have moved on. Achilles would then have reach the point that the tortoise had reached now, by which time the tortoise would have moved on. And so on, ad infinitum.

Of course Achilles does overtake the tortoise, and I believe the main issue in this case is related to the summation of an infinite number of decreasing distances, which intuitively one might this would sum to an infinite distance. In fact the sum of the distances is a finite number. If Achilles runs 10 times as fast as the tortoise and they start 10 feet apart then Achilles overtakes the tortoise after he has travelled 11 and 1/9 feet exactly.

Zeno’s paradoxes still inspire debate, but his conclusion was that movement, the smooth transition of something from one place to another is an illusion. One of the assumptions used is that distance is a continuously varying property, but it may be that it is not, and there are hints of that at the quantum level. The Planck length is the smallest distance about which statements can usefully be made and it is impossible to determine the difference between two locations less than one Planck length apart. Perhaps we do hop from place to place like chess pieces, or at least our atoms and their constituent particles do.

Space and time enable events to happen uniquely, and without collisions. Events may happen in the same place as long as they happen at different times. It may be that events of different probabilities happen at the same place and time, so long as the sum of the probabilities of all events is one. It may therefore be that probability is a dimension with the same sort of status as the space and time dimensions. This would require that our view of probability, of one event out of many being the one that actually happens is an illusion and that events of all probabilities happen in a sense.

## Considering the Universe

(Once again I wrote this on Sunday, but forgot to post it on Monday)

When we are considering the Universe we are considering something that we are part of, and of which we share the characteristics, such as, for example, existence. We can exist only because the Universe exists and the Universe exists, at least in part, because we exist. It is conceivable that in some way a universe could exist with nothing in it, much like a mathematical empty set but it would be pretty boring.

Or would it? Maybe I’m applying some anthropocentric reasoning to that statement. After all, the concept of a mathematical empty set is very useful in mathematics, and but then again, “useful” is a human concept.

A universe may be non-empty, but have no life in it. We, from another universe can conceive of such a universe, but there can be no perceiving of that universe if we rule out the possibility of visiting it from our Universe. We can’t even tell if such a universe exists, so some would argue that the question of its existence is meaningless.

That’s a valid argument, but then again, out Universe was not perceived by any entity in the billions of years prior to the evolution of life. Of course the question of the early  existence of our Universe before the coming of life, is not meaningless to us – we know that it must have existed for us to exist.

Of course, we can conceive of other universes other than our own, but do other universes exist in any real sense, apart from our own. A universe is self contained in the sense that there is no logical reason to conceive of anything outside of it. It is all of physics, all of existence.

One definition of universe is:

a distinct field or province of thought or reality that forms a closed system or self-inclusive and independent organization

This is a pretty good description of what I am writing about I’d say. The key word for me is “closed”. If something is closed it contains whatever it contains and the outside is irrelevant so far the contents are concerned.

Though now I come to think of it, maybe that is not true. If we have a can of beans, we know what is inside it by the label, and we can open the can with a can opener. Maybe the contents of our Universe are visible on the outside, on the label as it were.

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Our Universe has laws, or appears to have laws. The laws appear to be universal – that is, they apply everywhere in our Universe without exception. An atom here behaves the same as a similar atom here would and conceptually swapping them would make zero difference.

We do not know all the laws but we humans believe that we can know all the laws and I believe this to be true, even if it might take longer than the life of the Universe for use to discover and understand them all. By laws, I mean “how stuff works” and even if the ultimate answer is “because that’s the way the Universe works” and there is no deeper meaning than that, I’d still consider them laws.

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One bizarre possibility though, is that there is no order and the Universe is totally random, and only appears to have order. When we look at an expansion of the number Π we mostly find what seems to be random digits. Occasionally however we find runs of digits which look like they are non random, such as a lengthy series of the digit “3”, but eventually the random appearance returns.

This feature of the number Π can be used for amusement, such finding one’s own name “encoded” in Π, or any other string. Maybe our Universe is like a very long encoded string in the number Π, which seems to be ordered but actually isn’t. Maybe at some future instant things will revert to the real random state that the Universe is its real state.

Some physicists and cosmologists postulate alternate universes to account for some of the weirder facets of Quantum Physics, but in the broader sense we can consider universes which are similar but different and unrelated to ours. Would we want to visit such universes? Could we conceivably do so?

It seems to me to be unlikely that we could visit other universes, as the only methods that we could use are physical ones and our Universe encapsulates its physicality. That is, the physical laws pretty much define it. A frog can leap from a pond, since frog, pond, the air and the surroundings of the pond are physical, but simple leaping cannot take the frog to another universe, no matter how hard he jumps. A human can use physics to travel the Universe, but using physical means it doesn’t appear possible for us to jump out of our pond.

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Would we really want to visit other physics-based universes? The other universes would have to be pretty much the same physically, our physical bodies would suffer – imagine for an example a universe where protons decay in minutes instead of in aeons. We would die in seconds.

Our best prospects for universe-hopping would be those universe which are probability neighbours. That is, they share the same physics as our Universe, but some events happened differently. For example, one can contemplate a universe where slaving never happened or where France’s hegemony dominated the early USA and French language and culture dominate in the North Americas.

Of course, we are used to a physical Universe, but it is conceivable that other universes may be not physically based. It’s extremely difficult to even talk about such universes, should they (in some sense) exist, and my mind keeps trying to populate such conceptual universes with things, and things are presumably physical entities, and would not be able to exist in a non physical universe. Probably!

Perhaps our physical nature hampers us in understanding the real nature of things. Perhaps we can only conceptualise things based on our nature. After all our thoughts are the end result of physical processes evolving over billions of years and are implicit in the history of our Universe and encoded in a way in the Big Bang.