Many, but not all, laws of physics have been broken over the centuries. Some are actively being broken right now, which is a good thing, because that means there’s more to learn about the universe.
First off, the word “law” when it comes to physics has a bit of a loose definition, even among physicists. Sometimes the term applies to properties of the natural world that we have consistently observed to be true for a very long time. Sometimes the word is attached to fundamental ideas that form the bedrock of large, sprawling, complex theories of the cosmos. And sometimes it’s just a throwback term that doesn’t even apply anymore.
But no matter what, keep this important fact in mind: all knowledge in science, up to and including the most important laws, is provisional. It’s all based on the evidence. If the evidence changes, then we update our knowledge of physics, tearing down laws if we have to, and move on. That’s how we progress in our knowledge and become ever more sophisticated in our understanding of nature. That’s the most fun part of physics: We always get to learn new things.
With that said, there are some laws that are so central, so deeply studied and experimented, that it would take a lot of work to overturn them. The laws of the conservation of momentum, for example, finds utility in almost every single corner of physics.
Indeed, almost every theory of physics is basically a retelling of momentum of conversation but in different applications. It forms the foundation for basic mechanics (Newton’s F=ma is just another way to phrase it), gravitation, the theories of relativity, fluid mechanics, electromagnetism, and more.
In principle, we could be wrong about that law, and we as scientists must always stand ready to toss it aside, if need be, but in centuries of studying momentum conservation we’ve never, ever observed a violation of it, so it doesn’t exactly keep us up at night.
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Other laws, especially the ones that got that name historically but didn’t deserve the name, were overturned almost as soon as they were stated. One example is Bode’s law, proposed in 1715, which states that each planet should be roughly twice as far away from the Sun as the next planet inwards. The law works for Ceres, which predicted that there should be something in the region of the asteroid belt but failed after the discovery of Neptune. Nobody talks about Bode’s law anymore.
Then there are a bunch of in-between laws, and these are the most interesting. These are the laws that hold true, but as we discover more about the universe, we find that they are just a subset of a larger understanding of the cosmos.
For example, there’s Newton’s law of universal gravitation, which was a major revolutionary step in our understanding not just of gravity, but of the physics of the wider universe. He realized that every single object participates in the force of gravity, and that this connection could explain an apple falling from a tree (Earth is pulling on it) to the orbit of the moon (Earth is also pulling on it), to the tides (the moon is pulling back on Earth).
Newton’s formulation of the law of gravity is relatively straightforward. The amount of gravitational attraction between two objects is proportional to the masses of those objects, and inversely proportional to the square of the distance between them. Done. Newton’s law of gravity is so powerful that we can use it to calculate artillery ranges and send people to the moon.
But it’s also incomplete. Mere decades after Newton formulated his theory, physicists discovered shortcomings, like its inability to completely describe the orbit of Mercury. It would take the work of Einstein to extend our understanding of gravity and provide a more universal (and much more complicated) description in the form of general relativity.
Newton’s gravity still works in most of the universe, but in more intense scenarios, like around a black hole, or when more precision is needed, like when calculating GPS coordinates, you need to “break” Newton’s law and upgrade to relativity.
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Mysteries abound in the universe. We do now understand the nature of dark matter or dark energy. We do now know why the neutrinos have mass. We do now know what happened in the earliest moments of the big bang.
But we don’t understand what happens at the center of a black hole. Answers to some of these mysteries may lay within the bounds of the known laws of physics, in some form of that we currently can’t discern. Or maybe we need to overturn even our most closely cherished, most fundamental laws to explain these mysteries.
Either way, we get to learn something new.