Theories of everythings

[cosmolinguist]

On Monday I saw Martin Rees, astronomer royal, president of the Royal Society, etc.etc. give a general-audience lecture at the University of Manchester. This picture is by far my favorite of the slides he used to illustrate his talk.

When I was younger I couldn’t understand why the two specialties of physics that most interested me were the very big -- as documented in entries passim, I have liked astronomy for as long as I can remember liking anything -- and the very small -- I liked the LHC before it was cool, man! I didn’t know then what this pcture depicts so well: the biggest and smallest things in the universe are intimately connected.

Lord Rees pointed out a few interesting things about this image. If I’d been able to find a higher-resolution version on the internet it’d be easier to see that the numbers around the circle go from 10^-20 cm, (a decimal point, 19 zeros, and then a 1) the region of quarks and other smallest-things-we-know type things, up to 10²⁵ (a 1 followed by 25 zeros) cm, the size of galaxies.

For one thing, humans, down at the bottom of the picture there, are precisely located between these two extremes. There are as many atoms in a human body as the number of bodies it would take to equal the volume of a star like our Sun. We can appreciate the universe on both the very small and very large scales.

For another, if you look horizontally across this picture, there are connections in what you find there. Atoms and stars are related because it is through fusing atoms of one kind (hydrogen) into another (helium) that stars emit the heat and light they do. And those aforementioned galaxies and tiny subatomic particles are connected because it is through the motion of entire galaxies that we’ve had to admit dark matter, made of such tiny but as-yet myseterious particles, to the standard model.

My favorite, though, was when Lord Rees talked about the possibility of physics coming up with a “theory of everything” in the future, something that reconciles the differences we currently can’t ignore between the small, quantum-level universe and the huge cosmological-scale universe: the head and the tail of this Ouroboros snake. The rules we currently have for one don’t work for the other, though people have been trying to figure out how to merge them ever since Einstein first came up with our current best understanding of them. Einstein himself spent much of his life in the unsuccessful attempt to fit the two together, and no one since then has had more luck than he did. Thus this has become so much the holy grail of physics that even hipsters are aware of it.

But Lord Rees pointed out that it’s a misleading name, theory of everything. It’s hardly everything, he said. It’d be a theory unifying the fundamental forces, but it would mean nothing to, say, biology. Biologists would go on just as they are now, no better or worse off, because they’re worried about entirely different things anyway.

And this was the point I really liked; he said this Ouroboros image contains not two extremes, but three. Small (he indicated the subatomic particles), big (galaxies)... and complex. Here he circled the humans at the bottom of the picture. More than once during his lecture he said that physics is simple and biology is complex. I wouldn’t have argued with this thought, but I’d never thought about it this way before and being introduced to the idea like this was really delightful and really powerful.

Perhaps because biology has never been my strong point, never as captivating for me as particle physics or cosmology, so it’s easy for my eyes to glaze over when faced with anything less than David Attenborough explaining to me all creatures great and squishy. This seems to me, if only because of my biases in what I read and listen to, a rare case of giving biology its due in a physics-centered context, reminding us that despite there being so much that humans need to specialize, there’s nothing inherently separating these disciplines.

As a species with one foot in the quantum world and one in the stars, it can be easy to forget how marvelous those feet are, and it’s good to be reminded. So wiggle your toes, and remember to enjoy that delightful, delicious biology.

Comments

[tyrell.livejournal.com]

"The creator of the universe works in mysterious ways. But he uses a base ten counting system and likes round numbers."
- Scott Adams

[rocketeddy.livejournal.com]

Nice post. :)

I have a minor quibble with Lord Rees' stance - physics isn't about "simple" things, but rather physicists do their work by deliberately simplifying them in a way that isn't always possible with Biology.

For example, determining orbits of the planets and their moons in our Solar System is astonishingly complex if you want to take into account the truly accurate gravitational interactions between all the bodies involved (see the N-body problem (http://en.wikipedia.org/wiki/N-body_problem) and N-body simulation (http://en.wikipedia.org/wiki/N-body_simulation) on wikipedia if you're interested) but because of the nature of the system we can simplify it by simply ignoring the smaller interactions - it's not entirely accurate when we do this, but it's a close enough approximation for what we need.

Biologists do the same thing in some situations (such as modeling large populations) but the technique is less generally applicable.

Btw: 10^-20 has just 19 zeros after the decimal point >;-)

[cosmolinguist]

Of course it does! Quite right. This is what I get for trying to write when I'm too tired... Amended now, thanks!

[haggis.livejournal.com]

I think the middle ground, between the very large and the very small is more the region of engineering and materials science. It's useful stuff but doesn't spark the imagination in the way that particles and galaxies do.

My dad used to have a reductive saying that biology was basically chemistry, chemistry was basically physics and physics was basically maths. That's true in a reductive sense - the underlying principles of biology are chemical interactions and so on, but it's also true that as you move up that list from maths to biology, how the basic principles result in more complex and varied phenomena.

[wehmuth.livejournal.com]

Dunno if you've seen this, but it seems appropriate:
http://www.forkparty.com/the-scale-of-the-universe-interactive-flash/