Doug's Darkworld

Ah,  cosmology, the study of the origins and the nature of the Universe. The perfect topic for tying ones brain up into little crying knots, because frankly there’s all sorts of aspects of it that defy credulity, reason, and visualization. The perfect topic the end the week with then, because if one tries to understand cosmology hard enough, the brain will simply shut down in dismay … and you’re ready for a truly relaxing weekend.

Firstly, I’m not a cosmologist, so my understanding of this topic is pretty superficial and may even be entirely wrong in some respects. Still, I’ve been reading and thinking about it for a long time, and I think I have the gist of it down, or at least enough to explain it in a way that others can at least glean some understanding of my understanding of the topic. The second thing to understand is that this is a very wide open field and cosmologists themselves have very different ideas about what is going on here, so saying “debate continues” is an understatement.

I have covered some of these topics before, or at least the basics of them by discussing the Big Bang theory, Strange Lodgings, The Axis of Evil, and Dark Flow. And now that everyone understands the Big Bang theory … they can explain it to me. OK, that was a cosmology joke, and like cosmology, it’s hard to see the humour in it. Today I am going to try and explain what is “outside” the Universe and what is “before” the Universe. Or at least a  rough idea of some of the current thinking about these things as I currently understand them.

OK, first, the background. We are very used to thinking of things in a conventional four dimensional way, time being the fourth dimension. So much so that people often conceptualize the Universe as having come into existence into some infinite void, and that before the Big Bang there was this infinite void going back in time forever until the Universe appeared. This is because we are so enamoured of our view that the four dimensions we experience are simply the fabric of reality that we can’t imagine anything else. Well, this isn’t the case. There is no infinite void, there is no “outside” the Universe in any conventional sense, and there is no “before” the Universe. It’s not that there’s nothing, it’s just that whatever is “there” isn’t “there” in any sense that we can intuitively visualize.

In other words, time and space are part of the integral fabric of our Universe, but they aren’t part of the integral fabric of reality. They are embedded in reality, but reality itself appears to have at least ten dimensions. The best example I can think of is an MRI and how it shows a two dimensional slice of a three dimensional object. Well, the Universe is a four dimensional slice of a multi-dimensional reality. See, this is easy. Yes, the Universe is a cosmic MRI of reality itself in a  way. What cosmologists call our Universe as it exists in this multi-dimensional state is a brane. Well, sort of, it’s kind of an inflated brane, but remember that word.

OK, so we have this multi-dimensional reality, ten as I currently understand it. Fortunately five of those are “folded up” and never fully expanded. This means that besides up, and down, and sideways, our universe has five other directions perpendicular the the three we are used to. However in these five dimensions, the entire breadth of the Universe is some minuscule sub-atomic distance. Which obviously limits how far one can travel in those directions. Phew. Think what blueprints would look like if buildings had to have eight dimensions instead of three. Yerp, I can’t imagine that either, but I suppose if we had eight dimensional brains, it would be easy to imagine a seven dimensional blueprint of an eight dimensional structure.

So anyhow, in our five dimensional reality we don’t have space or a void, but what we do have cosmologists call the “bulk.” And “travelling” through this multidimensional reality we have at least two branes. It’s like a planet travelling through space, except the planet and space itself have extra dimensions so that visualizing this with our pathetic three dimensional brains is, well, impossible. And every once and awhile, like hundreds of billions of years in our time, though not necessarily in bulk time if there even is such a thing, these two branes collide. And when that happens we get … a Big Bang … and a universe such as ours “explodes” into existence with the release of unimaginable amounts of energy that this brane collision releases. Some cosmologists then have called this collision and subsequent Big Bang a, ahem, “brane storm.” See previous note about cosmology and humour, jokes like this are why few cosmologists ever successfully become stand up comics.

This then, in a horribly simplified nutshell, is what is called the Ekpyrotic Theory. Some physicists and cosmologists really like it because it does away with two of the problems with the basic Big Bang theory. It eliminates the need for the inflationary epoch, that was when in the first moments of our Universe it expanded much faster than the speed of light. I’ll do another post on the inflationary epoch sometime soon, but trust me, it’s one of the problems with the Big Bang theory. Secondly, apparently the Ekpyrotic Theory allow for a cyclic reality. That is, and I’m not sure I understand correctly, at some point in our distant future the Universe and energy is spread so thin that is “dissolves” back into the bulk somehow and becomes a pure brane again … which eventually collides with another brane … and another universe is created.

And the debate continues. Yes, the Ekpyrotic Theory does imply that there may be other Universes “out there” somehow, but they aren’t required. And while we can never actually confirm any of this with direct observation, apparently gravity crosses some of the “boundaries” between dimensions, at least on very tiny scales, like in our five folded up dimensions. This then is one of the things that the LHC (The giant atom smasher scientists are firing up in Europe) will be testing, the effect of gravity on tiny particles to see if something outside our Universe is influencing them. More on the LHC at some point too, but at least my gentle readers can finally get some sleep at night knowing that yes, there is indeed an answer to “What created the Universe?” aside from the logically and scientifically unsatisfying: “God did it.”

Have a great weekend everyone.

(The above image is a coloured version of the Flammarion Woodcut, an anonymous image from the nineteenth century. I’m claiming it as Fair Use under US copyright law. It’s not being used for profit, its central to illustrating the post, and its use here in no way interferes with the copyright holder’s commercial use of the image. I don’t know who to attribute this coloured version too, if I did I would link to therm and laud their fine work. And yes, my explanations above may have garbled or completely misstated some elements of cosmology, that’s what the comment section is for clearing up.)