The Beautiful Thing About Waves

As pseudoscientific woomongers will never cease to remind you, waves are everywhere.

For once, they're right.

Fundamentally, a wave can be defined as a disturbance that travels at some velocity v. These can be travelling waves (which are self-explanatory because, you know, they propagate from one place to another), standing waves (the usual example is a plucked guitar string - the string is fixed at 2 points and so the wave produced ends up interfering with itself), transverse waves (the wave oscillates perpendicular to the axis of propagation, as in a light wave), longitudinal waves (the wave oscillates along the axis of propagation, as in a sound wave), mechanical waves (the wave travels through a medium, as in ripples on a pond) and nonmechanical waves (for example, light again - it doesn't need a medium to travel through).

In other words, waves are all around us, from light to sound to pressure waves to ripples on a pond. I might sound like a five-year-old at this point, but I find that pretty awe-inspiring, that one phenomenon makes up so much of our daily experience.

What I find even more amazing is that all these seemingly disparate phenomena can all be described by the same equation:

For the non-mathematical among us, this is equivalent to saying that on a fundamental level all these phenomena can be treated in the same way. They are different manifestations of the same thing.

I have to confess that I never really liked waves before coming to university. I found them unintuitive and the equations I worked with seemed just about completely arbitrary. Having now derived them, and knowing that I'm going to derive a world-changing equation (I know every first year does it but I still just find it so damn awesome), I have so much more love and appreciation for them.

This links into why I like physics: in my friend's words, eventually everything connects. The phenomena around us might seem disparate and disconnected. Galaxies are different from stars, which are different from planets, which are different from the things you find on planets like projectiles, semiconductors and people, which are different from atoms, which are different from the bizarre world of subatomic particles. This is just common sense. Yet somehow it's turned out that we can describe trillions of objects with relatively few mathematical approximations. Keep in mind that there is no reason why this should actually be the case; the universe is under no obligation to make sense to us. It is perfectly possible to imagine a universe where every object is described by several unique equations, or one where the laws of physics change unpredictably. (Hey, I never said they had to be realistic universes.) It is so very beautiful and elegant, and at every turn of physics we've been able to unify more and more concepts, to describe more and more things with just a few mathematical statements. It gives me hope that one day we can unify them all, that there will be one thing to explain everything in our observable universe.

If I ever live to see it, it'll be the most beautiful thing I've ever laid eyes upon.