Warning: Self-Indulgence Ahead

This week is my birthday (a multiple of 5, so I suppose it’s a landmark by some people’s measures). As a result, I’m going to be even more self-indulgent this week than usual and talk about some slightly esoteric stuff that interests me; hopefully it might interest some of you too. My first bit of self-indulgence, however, is something more or less birthday inspired.

Recently, I’ve been seeing a lot of people talking about how important it is for scientists to tell stories, to inspire, to provide a narrative for the work we do. Alan Alda, who has made science advocacy a large part of his life, recently called out for scientists to inspire non-scientists to the same level of passion they themselves experience. (I have more to say about the kind of advocacy Alda does later.) I don’t know if my mere blog is good enough for that, but I thought (inspired by this blog post) I’d try my hand at telling my personal story in brief.

I’ve already told part of the story through my interactions with the third-grader who wrote to me (part 1 and part 2). The short version is that when I was young, I was fascinated by the pictures taken by the Voyager spacecraft exploring the giant planets in the outer Solar System. That was certainly the time I started recognizing the universe is large (though nowhere close to grasping the full size!).

As I got older, I started reading science fiction and books about some of the crazier astrophysical objects out there: black holes, neutron stars, and white dwarfs. (Some books whose titles I remember: Our Universe by Roy A. Gallant, Frozen Star by George Greenstein, and About Black Holes by Isaac Asimov.) Looking back, I’m not sure how much I actually comprehended from these books, but I was fascinated by the subject and thought about it a lot. However, space flight was still more interesting to me, and I thought I’d rather be an aerospace engineer than an astrophysicist; I think I had some idea that I wouldn’t like the math involved in pure physics. (Those who know me are laughing right now.)

By the time I got to college, I had chosen to major in physics, since that was the obvious choice at the small liberal arts college I was attending. (Funny how they didn’t have a full aerospace engineering lab at a school with 1500 students….) I struggled in introductory physics, though certain topics intrigued me towards the end of the third term (we were on a trimester system): relativity and quantum physics. My second year began with an intensive modern physics course, similar to the one I’m teaching now, and as I started learning quantum mechanics in earnest, I realized that theoretical physics might be a real possibility for me. My math classes got more interesting the more complicated they grew, so that calculus, linear algebra, and differential equations, difficult as they are, inspired and challenged me rather than made me want to turn back. By my third year of college, with the upper-level theoretical physics courses in my schedule, I was truly hooked.

The things that fascinated me then aren’t exactly the same things as now. Then I was obsessed with an esoteric corner of physics known as quantum measurement theory, which was (not coincidentally) my advisor’s area of interest. Quantum measurement theory grapples directly with the weirdest aspects of quantum mechanics, which are often illustrated with thought experiments like “Schrödinger’s cat”. One example (which I’m likely to elaborate on later when it comes up in my quantum mechanics class this term): if you have a system of linked particles, then you break the link so that the two particles are travelling in different directions, measurements on one particle determine what the measurements will find on the other particle—even though no communication can pass between them. This kind of thing bugged Einstein no end—he called it “spooky action at a distance”; it certainly bugged me, and it might understandably bother you too.

I would say most students learn to live with the weirdness, since quantum theory is so successful, and the weirdness doesn’t intrude itself on most of what ordinary physicists do on a day-to-day basis. As for me, I started studying general relativity and the many attempts to reconcile it with quantum theory (attempts which are still incomplete after all this time). About that time, dark energy was discovered—the mysterious property that is causing the expansion of the universe to accelerate. I guess given my penchant to think about the “big questions” and my interest in gravitation, cosmology was the obvious end point for me. So, off to graduate school, and work in gravitation and some pretty obscure corners of mathematical physics in the name of understanding how general relativity might be modified to solve the dark energy problem. Despite my dislike of MOND, I’m sympathetic to attempts to modify gravity. (I’ve mostly avoided advocating for one alternative over another, since advocacy isn’t a good approach to finding out whether a theory is correct or not.) My work in cosmology has always come back to that question: is general relativity the “correct” theory of gravity, and how can we test it and its competitors?

If I may be allowed a moment of self-reflection, I worry sometimes that others might perceive that kind of work as being a bit crackpot. It’s not particularly mainstream, certainly not easily explained to others. I don’t think I’m a crackpot (what crackpot ever does?); after all, I’m not someone who thinks he’s got it all figured out and all he needs to do is convince others. I don’t have it figured out; I don’t know the right answers to the problems. Maybe if I’d picked a different set of questions to try to answer, I’d be in a different place doing something completely different. It’s a hard thing to know. As I face a probable major change in my career path, I still think those questions are worth answering.

I also think it’s wonderful to keep learning, and to share what I’ve learned with others. So, along with my diatribes against creationism, expect me to keep talking about stuff like MOND, quantum measurement theory, and (coming up soon!) a way of studying the structure of the universe using galaxy clusters that was pioneered by a Russian physicist who shares my birthday. I hope I can make these subjects interesting for enough of you.

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