It’s Tuesday now, and I’m writing this post on my smartphone, because I couldn’t be arsed to bring my laptop back from work with me last night. Perhaps this entry will therefore be more concise than usual, but I wouldn’t lay heavy money on it. It’s more likely than winning the $1.9 billion Powerball Con Game, but that’s not saying much. Getting struck by lightning during a shark attack is probably more likely than that.
There’s a full lunar eclipse in progress as I write this, and the umbra has about halfway covered the moon. I took a snap with my smartphone as I left the house and then more when I got here to the train platform. I’ll share some of them below. They are not of very good quality‒and the first one is just streaks of light, because apparently I was too excited to keep my phone still while taking the picture‒but then again, in the days before smartphones, I wouldn’t have been able to take such a picture at all.
The last time I recall watching a lunar eclipse with any degree of attention was back when I was in either junior high or high school, and I had a very cheap telescope on our back deck (This was quite a bit later than the reminiscence I described yesterday). I have to say, the one happening now is quite a bit more impressive than the one I remember. The shadowed portion of the moon is almost completely black, and the encroaching edge of the Earth’s shadow is quite, quite different than the usual arc of the moon’s own phases. It’s fascinating.
I forgot again to work on editing my audio recording of thoughts about time yesterday. I feel like I want to make some excuse, and there are surely reasons, or at least causes, but it doesn’t really matter what they are. So, now I’m going to try to rehash those verbal thoughts to give you all either a preview or‒more likely‒a replacement for the posting of those spoken words.
I was triggered to talk about time when watching a science video in which someone pointed out, as people often do, that we are able to travel rather freely in any of the three dimensions of space, but that our direction in time seems entirely one dimensional, and we don’t seem able to choose our direction or speed through it. But this is a slightly misleading characterization of the situation, I thought, and that thought is not entirely original nor unique to me, but this is my way of thinking about it.
It’s true that, if we were in deep space, especially in one of the gargantuan intergalactic voids (where light from all the surrounding galaxies would be too faint to be visible), there would literally be nothing to differentiate up from down, left from right, forward from backward, or indeed, any of these axes of motion from the others. But that’s not the situation in which we find ourselves. We are on the surface of a planet, in the presence of a rather strong gravity “well”, and that changes very much the way we experience the three dimensions of space.
Ignoring the facts of terrain, and thinking back to before we had modern technology, it’s clear that, while we are basically free to move forward and back and left and right‒and indeed, we can swap those axes out arbitrarily‒we are not free to move up and down at will.
Even birds and insects and bats cannot freely move through the up-down dimension, not in the way they can move along the curved plane of the surface of the Earth. It requires great effort for them to change their height, and they are limited by that effort and by the density of the air through which they swim. Because we are near a source of strong gravity, there is a clear directionality to one of the dimensions of space, and the only reason we don’t keep falling down is that there’s a planet in the way, but if it weren’t there would be nothing pulling us in one direction.
In a somewhat analogous sense, the only reason there seems to be a directionality to time is that we are near (in time) the presence of a region of very low entropy: The Big Bang. Since that time, about 13.8 billion years ago, entropy has been steadily increasing, as is its tendency, for fairly simple, mathematical reasons that make the 2nd law of thermodynamics among the most unassailable of all principles of physics.
All the processes that cause us to experience a directionality to time are driven by the tendency for entropy to increase, and that includes the clumping of matter under gravity, the growth of biological organisms, the accumulation of memory, and the development of technology. Increasing entropy‒on the largest scales‒is all that allows temporary decreases of entropy locally. Put poetically, it is only the inevitability of death that allows life to exist at all.
But of course, in the future, as entropy increases, life and local order will be no more possible than they would be in intergalactic space. Once entropy increases enough‒and the vast majority of the existence of our universe will be in such a state, just as most of space is not near the surface of a planet‒there will be no way even to know which direction of time would have corresponded to what we now think of as past and future, because the laws of physics are locally time-reversible. Time in that epoch would be no more uni-directional than space is in the vastness of an intergalactic void.
What’s more, it’s clear based on special and general relativity that time is not purely one dimensional. Time and space bleed into each other depending on relative motion and local spacetime curvature. That which can curve is not, strictly speaking, entirely one-dimensional in a Euclidean sense.
All this makes me wonder if, perhaps, the Big Bang era is not strictly a “plane” orthogonal to the time dimension, but might in fact be the surface of a sphere…or, well, some manner of hypersphere in space time, the surface of which is all at one “moment” just as the surface of a planet is all‒more or less‒the same distance from its center.
If so, then the Big Bang need not have happened merely in one direction in time. Others have toyed with ideas like this*, with the thought that there might be a sort of mirror image universe to ours, extending the other direction in time from us, its future analogous to our past. I’ve even occasionally wondered if the (very slight) relative abundance of matter over antimatter in our direction of time would be mirrored by a relative abundance of antimatter in that universe**.
But on further thought, I’m led to wonder if there need be merely two mirror universes, delineated by the Big Bang, heading in opposite directions. Perhaps there is a continuum of such directions, just as there is a continuum of “up” directions from the surface of the Earth. Perhaps our expanding universe has more in common with the expanding size of a sphere around the Earth’s center, which gets larger and larger as one moves away from it, and the Big Bang is not so much a beginning of time or the universe as it is a local area of low entropy in time, allowing the existence of phenomena‒including life‒near its surface that experience a difference locally between past and future only because they exist in an entropy gradient.
Perhaps, far out in the “future” of the universe, there might exist other local entropy minima, in any direction in time from us‒directly ahead or even at right angles in time to us, or any combination thereof. Of course, “reaching” them would be harder than traveling out into intergalactic space, given that they would probably exist across unguessable gulfs of timeless “time”***.
How would we even measure or pass through time in a region in which entropy was near-maximal and time was without any inherent direction? Perhaps if it were possible to accelerate continuously to near enough the speed of light that one’s personal time slowed ever more and more, one could survive to arrive at a place where entropy would begin to decrease. But what would that even be like? Would one enter such a realm as if a traveler from its future, moving‒to any local residents‒backward through time?
I could go on and on about these ideas, and maybe I’ll explore them more in future (ha) posts, but for now, I’ve taken enough time (ha ha). This was certainly not a concise blog post, but I hope it was at least intriguing. I’d be interested to hear your own thoughts on such matters.
In closing, I’ll just ask the following thoroughly fanciful question that just popped into my head: What would happen to a werewolf during a lunar eclipse?
*For instance, The Janus Point by Julian Barbour, deals with some similar concepts. I haven’t finished reading the book, but I thought of the ideas I’m discussing before I’d encountered it, and my ideas are somewhat different, though far less expert than his.
**Though they would surely switch the terms, calling our antimatter their matter.
***And reaching the portion of our universe that heads in the opposite direction in time would seem to require exceeding the speed of light, which appears to be impossible‒though perhaps wormholes might lead to such places, if they in fact exist.
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