Category: symmetry

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.

This One Award Was The Biggest Injustice In Nobel Prize History

“Every October, the Nobel foundation awards prizes celebrating the greatest advances in numerous scientific fields. With a maximum of three winners per prize, many of history’s most deserving candidates have gone unrewarded. However, the greatest injustices occurred when the scientists behind the most worthy contributions were snubbed.”

Imagine this scenario: you work hard all your life investigating some aspect of reality with as much scientific rigor as anyone ever has. You make a great breakthrough working on a very hard problem, and you push your scientific field forward in a novel, important, and unprecedented way. And then, when the time comes to evaluate the quality and impact of your work, it’s chosen as being Nobel-worthy. 

Only, when they announce the winners of the Nobel Prize, your name isn’t called at all. Instead, other scientists are awarded the prize, while both your name and your decisive work are omitted from every aspect of the award. Sounds like a pretty big injustice, yes? 

Well, it’s happened to many people over the years, including Chien-Shiung Wu in perhaps the greatest injustice of them all. Come get the full story on the eve of the 2019 Nobel Prize in physics being awarded!

Ask Ethan: What Does It Mean That Quantum Gravity Has No Symmetry?

“What does it mean that quantum gravity doesn’t have symmetry?“

Last month, a scientific paper was published in a prestigious journal, entitled: Constraints on Symmetries from Holography. It states that three long-standing conjectures about quantum gravity, including one stating that quantum gravity does not allow global symmetries of any type, have just been proven if the holographic principle, and by extension the AdS/CFT correspondence that’s fundamental to string theory, is correct.

This is really, really big news. If there are no global symmetries, then there are no absolute conservation laws. Energy is not conserved, momentum and charge are not conserved, and additionally all sorts of things that are not forbidden but not observed, like magnetic monopoles, must necessarily exist. 

Paradoxically, if string theory is right, our expectations about hidden symmetries revealing themselves at a more fundamental level are not only wrong, but that nature has no global symmetries at all.

Come get the full, fascinating story, with all the deep implications that come along with it, today.