Category: lorentz

This Is The One Symmetry That The Universe Must Never Violate

“In physics, we have to be willing to challenge our assumptions, and to probe all possibilities, no matter how unlikely they seem. But our default should be that the laws of physics that have stood up to every experimental test, that compose a self-consistent theoretical framework, and that accurately describe our reality, are indeed correct until proven otherwise. In this case, it means that the laws of physics are the same everywhere and for all observers until proven otherwise.

Sometimes, particles behave differently than antiparticles, and that’s okay. Sometimes, physical systems behave differently than their mirror-image reflections, and that’s also okay. And sometimes, physical systems behave differently depending on whether the clock runs forwards or backwards. But particles moving forwards in time must behave the same as antiparticles reflected in a mirror moving backwards in time; that’s a consequence of the CPT theorem. That’s the one symmetry, as long as the physical laws that we know of are correct, that must never be broken.”

Are the laws of physics the same, here and now, as they are at all other times and places in the Universe? If they are, then that means a certain symmetry exists. It appears, to up to 18 orders of magnitude in some experimental cases, that specific symmetry is good and respected by our Universe. If a theory demands its violation, that theory is presently unsupported by all of the evidence. The reason? 

One particular symmetry, known as CPT, that the Universe forbids us from violating.

How To Prove Einstein’s Relativity For Less Than $100

“But the fact that you can see cosmic ray muons at all is enough to prove that relativity is real. Think about where these muons are created: high in the upper atmosphere, about 30-to-100 kilometers above Earth’s surface. Think about how long a muon lives: about 2.2 microseconds on average. And think about the speed limit of the Universe: the speed of light, or about 300,000 kilometers per second. If you have something moving at the speed of light that only lives 2.2 microseconds, it should make it only 0.66 kilometers before decaying away. With that mean lifetime, less than 1-in-10^50 muons should reach the surface. But in reality, almost all of them make it down.”

Relativity, or the idea that space and time are not absolute, was one of the most revolutionary and counterintuitive scientific theories to come out of the 20th century. It was also one of the most disputed, with hundreds of scientists refusing to accept it. Yet with less than $100 and a single day’s worth of labor, there’s a way you can prove it to yourself: by building a cloud chamber. An old fishtank, some 100% ethyl or isopropyl alcohol, a metal base with dry ice beneath it and only a few other steps (see the full article for instructions) will allow you to construct a detector capable of seeing unstable cosmic particles. Yet these particles – and you’ll see about 1-per-second – would never reach Earth’s surface if it weren’t for relativity!

Come learn how you can validate Einstein’s first great revolution all for yourself, and silence the doubts in your mind. Nature really is this weird!