Hello and good morning. As usual, it’s Thursday—well, that’s only usual on one day of the week, but since this is that day of the week, it’s usual on this day—and so it’s time for my weekly blog post.
I’m feeling pretty exhausted today, partly because of a temporary change in work schedule that’s throwing my mental functions into a minor tailspin, and partly because of frustration associated with trying to get feedback and do useful research about my neurophysiology through the advice or input of people with expertise in the matter. Some of the fault is mine—I have a hard time forcing myself to initiate or undertake most interactions, including contacting and setting up some form of new relationship with a new therapist…or doing therapy at all.
I also get distracted—and I suspect that some of the people I’ve tried to contact have done so as well—by the ongoing issue of my dysthymia/depression, which is certainly troubling, but which is an old companions of mine and unlikely to improve. But there’s only so much one can get from YouTube videos and reading, whether it’s technical literature or works aimed at laypeople. And I have a terribly difficult time even contemplating joining online support or discussion groups (or “in person” ones, which seem even more intimidating and disruptive). I may be stuck. I feel stuck. I could really use some help—of various kinds—but the very prospect of seeking it is too daunting and confusing, and it is further hindered by the fact that I feel, deep down, that I don’t really deserve any help of any kind.
On the other hand, work on In the Shade is proceeding reasonably well, as it has been for some time. I’m doing a nice job trimming it down, at least as far as raw numbers go. I hope it improves the story; it would be a shame if it made it worse. In any case, though, I’m more than halfway through the overall editing process, and that’s a good thing.
A thought popped into my head this morning that has popped in many times before, and I’m tempted to send emails or similar to the likes of Brian Greene just to see if he can clarify anything about it. But I would feel quite cheeky and rather obnoxious to trouble him, even if I could find a way to send him a query.
Roughly and briefly, the thought is related to the ideas of “M Theory”*—which encompasses more “traditional” string theory as I understand it—and the notion that our entire three-dimensional universe might be a “brane” embedded in a higher-dimensional “bulk”, and that we can only experience the three dimensional universe in which we live because we—all the force-carrying particles and matter particles of which we are made—are trapped within the brane, possibly because they are composed of open-ended “strings”. However—again, if I understand correctly based on the reading I’ve done—the graviton, the hypothetical force-carrying boson of the gravitational force, would be a closed string, and could, if there are branes and a bulk and so on, travel between branes. The hypothesis has been put forward that this might be part of the reason gravity seems so weak; it is not as narrowly confined dimensionally as the other forces, and so spreads out to a greater degree.
I played with some of these ideas very indirectly in The Chasm and the Collision.
Anyway, my thought was that, perhaps, this could provide the explanation for the apparent existence of “dark matter” which is proposed as the presence of a large amount of mass in the universe that doesn’t interact much with “normal” matter, or with light, but which has gravitational effects measurable in the speed of rotation of galaxies and of the interactions of galactic clusters and so on, and which, based on those various measures, would be about five times as abundant as “normal” matter. But no one has been able, so far, to detect the presence of any such dark matter particles, which would be presumed to interact at least occasionally with normal matter in some way.
It’s proposed as possible in M Theory that there could be other parallel “three-branes” in the bulk, “next to” ours in higher-dimensional space, analogous to planes or pages that float, aligned but not touching, in three-dimensional space. If most fermions and bosons are stuck in their branes but gravitons can more or less freely pass between them, and if parallel branes came into existence—in their current states, anyway—roughly at the same time, so to speak, then as those universes expanded and evolved, with initial quantum fluctuations leading to increasing clumping of matter, leading to galaxies, stars, etc., they would have influenced each other’s clumping, and so a galaxy in one brane might well tend to be “near” or roughly lined up with, a galaxy in nearby branes, and so on. If so, and if gravity can, at least to some degree, pass between branes, then the vector components of such gravity that happens to align with the nearby branes’ dimensions might well be felt as an “extra” gravitational force without any source in detectable matter.
If there are multiple branes in parallel to each other—or perhaps even a limitless stack of them, so to speak—depending on their separation and the degree to which gravity can pass between them, the net effect might well be enough to generate the phenomena we measure as evidence of “dark matter”. If one were only thinking of, say, a four-dimensional space between the three-branes (with other dimensions curled up small), the force of gravity between matter in them would presumably fall off at a rate of one over the distance cubed, but if there were multiple branes in parallel, and again, if the distance were right and the properties correct, then I don’t see why it couldn’t accumulate to give a net effect greater, on large enough scales, than the apparent impact of gravitating mass within a given brane.
Unfortunately, my math skills are not presently up to the task of even doing a “back of the envelope” calculation about how that might work, though I have tried from time to time. I also don’t know much of the technical details about string theory/M Theory. And, of course, the whole theoretical framework is troubled by difficulty creating measurable predictions, at least with current technology. But…if such parallel branes could in fact account for “dark matter”, they would, if correct, predict that there would be no measurable dark matter particles. Ever. And so, of course, the longer we go without being able to find one, the more our Bayesian probability might edge toward the correctness of at least some version of M Theory. Of course, if dark matter particles are found and have characteristics that explain the phenomena we see, then that would at least disprove my notion, if not all of M Theory.
It’s likely that such a notion is already ruled out by some specifics details that I just don’t know—which must of course be almost all the specifics of M Theory.
Maybe some day I’ll work up the courage to forward some version of this to someone like Brian Greene, or maybe Lisa Randall or Leonard Susskind**. But probably not. I have a hard enough time mustering the nerve to talk to anyone regarding my own neurological and psychological health. And, in any case, those people have enough on their minds. And I have books to write. And—unfortunately—miles to go before I sleep.
In the meantime, I hope you all stay well and do your best to take care of yourselves and of those who matter to you—and also, while you’re at it, do your best to avoid causing problems for other people.
*Which is, of course, speculative to say the least, but which is certainly intellectually interesting, and which could, in principle, be a description of the deeper physics of our universe.
**These are the three physicists from whose popular works I’ve learned most of what I “know” about such matters. I first encountered string theory and M Theory in Stephen Hawking’s book, The Universe in a Nutshell, but alas, no one can get any messages to him anymore—or, at least, we can’t get any messages back.