Friday, February 15, 2008


I love xtcd.

I spend a lot of time thinking about chemistry and physics. I have had lots and lots of school and lab time, and I'm lucky to do science for a living.

But there are lots of things that I still find mysterious and weird. Magnets and gyroscope do things that seem completely magical to me. Yes, I've done the math. I barely apprehend the fact that conservation of angular momentum stems from the rotational symmetry of space, and I have worked through the basic relativity to see that magnetism is sort of a consequence of this. I know lanthanides are contracted due to relativistic effects.


Somehow, a magnet rotating downtown makes my lights shine and my computer run. Yes, yes, magnetic induction, Maxwell's equations. Very nice. So why? Why do the electrons in my lamp give a shit what the big magnet downtown is doing? Knowing the math is not the same as knowing the reason. It's deep, and mysterious, and yet so ubiquitous that it is easy to ignore. My lamp ignores the movements of paired electrons. But not those that are unpaired and aligned. I am happy to use electricity, and I feel especially fortunate to have been schooled in physics as an undergraduate. But I am still not satisfied. I don't care if the universe has 3 dimensions or 21. I want to really, really know why my gyroscope doesn't fall over, and why magnets stick to my refrigerator. So I keep poking at physics and mathematics long after my mental prime, hoping I'll get it someday.

Lately I've been playing around with symmetry and Lie (pronounced 'Lee') groups. Symmetry has deep connections with physics, as I alluded to above. Chemists get just a little taste of symmetry and group theory, when they learn how to use point groups to predict the bonding and spectral characteristics of molecules, usually in an inorganic chemistry course. The presentation is usually abysmal, with no foundational theory, and very little motivation. You learn to 'do' group theory without really understanding it. In fairness, it is usually shoehorned into an already filled-to-the-brim survey of all the chemistry not covered in organic, which is, by virtue of the peculiar properties of carbon, pretty unique. If you know only organic chemistry, you still know a lot of what is done in the chemical world.

What I am fiddling with now has little direct connection to chemistry, or at least not that I am able to see. I am looking at it as more of a means of retaining and rebuilding my abstract mathematical skills (since I have forgotten a lot of the analysis and topology I once knew.) What I am interested in doing is tying together a functioning understanding some of the more modern methods of mechanics and field theories (which tend to center a lot on differential geometry). At some level, deep topological symmetry and fields reconnect with statistical mechanics and hence condensed matter physics and chemistry, but I am not sure I'll ever get good enough to see this clearly. I'll be happy to know some of the basic ideas. Every time I've put in serious effort to understand stuff over my head, I get at least something that helps me understand more prosaic stuff, like chemistry...


At Saturday, February 16, 2008, Blogger Ψ*Ψ said...

XKCD rocks my world.
Undergrad physics almost killed the subject for me. I still find it interesting and useful on a more conceptual level, but...since the spatial part of my brain is apparently dead, a lot of it will remain a mystery.

At Saturday, February 16, 2008, Blogger David Eaton said...

I wish I had worked harder as a physics undergrad, mainly. I squandered the period when my mind was at its most nimble, and when I had so much more time than I do now.

My wife used to complain about spatial perception being hard for her. She got involved in carpentry through Habitat for Humanity, and says that it gets easier the more she does.

From what I can tell, she still thinks non-spatially, but doing stuff in 3 dimensions has provided her with other ways of processing the info.

At Saturday, February 16, 2008, Anonymous Killer_Acenes said...

I spend a lot of time wishing I was smart. I've been listening to the Feynman lectures on physics, particularly the parts on special relativity. I keep getting this horrible, nagging feeling that it's all just WRONG. When things move fast, they get shorter. And heavier. Hmmm? Yeah, a lot of this has ben verified experimentally - sure. But I've been chasing a lot of problems, and thought I had things nailed down, when an even simpler explanation popped up, that both fit the current data and made sense of some annoying unknowns. What if we've got it all wrong? How horribly are we held back in energy, propulsion, space travel just because we have a theory that more or less makes sense of what we can observe? Wish I were smart enough to figure it out - I guess that's a problem left to the next generation. Is Sam reading Griffith's book on E&M yet?


At Saturday, February 16, 2008, Blogger David Eaton said...

I've been right on the verge of concluding that relativity is essentially an optical illusion, that it has something to do with our inability to use light to measure things that are going really fast. I think that there's more to it, but I doubt it's exactly what is current dogma.

I think that, maybe, particles move through space through an interaction with space, and the trying to go faster than light gets close to 'breaking' space. Mass and energy being the same thing is a reflection of this. Space isn't nothing, it's either a separate thing, or it is interactions between particles. I guess. I think you are right about the fact that we damned well might just be wrong. So much of science is dominated by brilliant technicians who hew to orthodoxy. The more mathematical, the more beguiling it gets. I'd bet money that some of the current cutting edge is unmitigated bullshit, especially some particle physics. Particle physics is particularly degenerate because it has dislodged from experiment.

Sam likes math, and I seem him staring at stuff like my physics books like they are hieroglyphics, as if he were just itching to know what they mean. He'll get there- he resents not understanding things.


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