Discoveries

Theoretical physicists “discover” the laws of nature.

What I mean by this is that the laws of nature can’t just be made up. Sure, a physicist can make up any theory that strikes her fancy; however, it doesn’t become a law of nature without rigorous experimental testing.

Suppose I make up a mathematical model that describes how objects move when you let go of them near the surface of Earth. I could “predict” that any object I let go of is going to stay more or less where I leave it. This is what happens when I let go of a glass of water on a desk, for example.

However, I would immediately find simple experiments that contradict the predictions of this model. Without a desk in the way, my glass of water would fall to the ground and probably shatter!

My made up model is WRONG. Objects you let go of tend to fall down to the ground.

As an aside, my model may not be entirely wrong for the special case of astronauts letting go of objects while in free-fall, perhaps aboard the International Space Station. But we already have a good explanation for how this happens!

Because experiments determine what can be a valid law of nature, it’s worth asking the following. How many laws of nature exist? And if it’s a finite number, what are theoretical physicists going to do when all the laws of nature have been discovered?

While I’m happy to say that it’s unlikely we’ve already discovered every law of nature, I’m intrigued by the fact that each law of nature is only discovered once.

Isaac Newton came up with his law of universal gravitation. Nobody else can discover that one. It’s already known.

Of course, it has limitations. It doesn’t work so well for very massive objects. This provides Einstein with an opportunity to discover his general theory of relativity.

And any limitations of Einstein’s work may lead others to discover new laws of nature.

While it’s possible for two physicists to discover a single law of nature independently, once it’s known, it’s known. No other physicists can later claim to make that discovery. They can find better ways to express it. They can work out new consequences. But they can no longer discover it.

The history of science includes a lot of discoveries. It’s definitely worth celebrating who manages to make the more significant ones!