Heads up: Garrett Lisi Ted Talk

Well, looks like this will be my first embedded video.

If you haven’t heard of Garrett Lisi, behold! He’s a surfer with a PhD who gained a tremendous amount of popularity over the past year with his “Remarkably Simple Theory of Everything” that he came up with while living in his van with no steady job. He has come up with a way to use a mathematical shape to categorize fundamental particles.

As a little precursor, let me just give you an idea of what he’s actually showing in the videos on his slides. Imagine taking a soccer ball, and a sack full of coins of many currencies (dollar, pound, yen, etc.). You could try to categorize the coins based on similarities between them by placing them on different hexagons on the soccer ball. You could start with the Canadian coins and lay them on the hexagons in increasing denomination. Then do the same with the American coins and so on. Each time you would make sure that the similar coins of different currency — for example Canadian vs. American nickles — are next to each other.

A remarkably inexpensive soccer ball

This is an analogy (that should be taken with a big pinch of salt) of what particle physicists have been able to do with particles and higher dimensional mathematical shapes instead of coins and soccer balls. Garrett Lisi is suggesting that he has found a better “soccer ball” to put the particles on. The difference between his soccer ball and the one shown in the picture shown above is that his soccer ball extends into more than three dimensions, so the only way he can show it on a screen is to “project” it into two dimensions. In a way he’s showing you the shadow of his soccer ball and then rotating it to show you the different ways the particles are grouped. Hopefully that will at least give you an idea of what you’re looking at.

I should also at this point mention that this is not yet an accepted scientific theory. It still needs to be proven and fleshed out. There are several problems with it that Bee pointed out about a year ago:

To make predictions with this model, one first needs to find a mechanism for symmetry breaking which is likely to become very involved. I think these two points, the cosmological constant and the symmetry breaking, are the biggest obstacles on the way to making actual predictions.

[...] I’ve complained repeatedly, and fruitlessly, about the absence of coupling constants throughout the paper, and want to use the opportunity to complain one more time.

Hopefully the data that will eventually come from the LHC will have something to say about the correctness of this theory and many others like it. Despite its downfalls, it really is quite pretty.

Update: A great “theory of everything” joke via Telescoper:

A string theorist arrives home one evening. When he goes into his house, his wife tells him that she’s hired a private detective who has been following him for the past week and she now knows he’s having an affair with another woman.

“But darling…” says the string theorist. “I can explain everything.”

Dragons at the LHC? (a spoof)

There’s a nice summary of what the LHC might find over at Resonaances. Maybe you won’t find the last two items as funny as I do, but, I find them hilarious. Here’s a taste:

Dragons. Probability $e^{-S_{dragon}}$
This possibility was recently pointed out by Nima Arkani-Hamed. The laws of quantum mechanics allow anything to happen, albeit the probability may be exponentially suppressed for complicated (large entropy) objects. CERN officials maintain there is no imminent danger since the putative LHC dragons will be microscopic (small dragons have the smallest entropy, hence the largest probability to appear in particle collisions) and anyway they will quickly suffocate in the vacuum of the beam pipe. Some researchers, however, have expressed concerns that the dragons might survive, grow, burn ATLAS, kidnap ALICE and lock her in a tower. A more comprehensive study of the potential risks is underway.

Black Holes. Probability $0.1*e^{-S_{dragon}}$
Although microscopic black holes have smaller entropy than typical dragons, the advantage of the latter is that they are consistent with the established laws of physics, whereas TeV-scale black holes are not. There are many indirect arguments against TeV scale gravity, from precision tests, through flavor physics, to cosmology. Certainly, dragons are a bit safer bet.

Ok people, place your bets before the first beam…

Everybody’s talking about it…

The LHC is sending its first beam through the coils of supercooled magnets that run through a giant underground tunnel of 27 kilometer circumference. It all happens September 10th (tomorrow). Physicists and fans around the world will be crossing their fingers hoping for a flawless start up. Although there won’t be any collisions today, tomorrow is symbolic of an 8 billion dollar, 11 year excursion that has finally come to an end. Now, the physics starts. If we’re lucky, we won’t just find what we’re looking for… we’ll find even more.

The wonderful blog, Cosmic Variance, is doing a live blog post of the events leading up to the first beam injection. Some of the readers are also placing their bets on what it will find.

A limit to our knowledge?

Over at backreaction, Bee posted some nice questions about the present and future of physics and askes whether there will be a limit to our knowledge. There are a hoard of responses to that post as well.

“Phenomenology” is the word of the day, and sometimes I can’t but wonder what if that fundamental theory – should it exist – indeed does not make any testable predictions. Just consider it for a moment: There is a fundamental theory, but it makes predictions only in ranges far outside what we can measure. With the focus on phenomenology, aren’t we then potentially discarding the path to go? It is not even that I believe it to be the case that a theory of quantum gravity would not have observable effects, but that possibility certainly exists (and who cares what I believe). So then what? What can we know? Can we know what we can know? What will happen to physics? Would the pursuit of such a theory still count as science?

For those who aren’t aware as to what she is referring, Bee is talking about a Theory of Everything (TOE) that physicists are spending much of their time searching for nowadays. A TOE would be a theory that simultaneously describes all particles and interactions between them via the four fundamental forces (Electromagnetism, Gravity, Strong Force, Weak Force). So far, gravity is the renegade force that is causing us problems. It just doesn’t like to play nicely with the others. When we try to combine it in the same way that was used to combine the other forces, we get gobbledygook results and infinities that can’t be swept under the rug. So far, String Theory has been the popular candidate for a TOE, but so far it hasn’t made any testable predictions, which is a major criticism of the theory.

I personally don’t think that there should be any need to worry about a TOEs predictions being permanently outside the range of what we can measure. Certainly there will be a limit to how big we can build a supercollider, but eventually, I think we will be able to test predictions simply by looking into the sky and studying the remnants of the Big Bang, which is surely the largest explosion we could possibly study. Let me explain. The deeper into space one looks, the farther back in time one looks also (since the light takes some time to get here). So looking deep into space we eventually see what is now called the Cosmic Microwave Background (CMB). This is the light from the stage in the universe’s evolution when the dense “soup” of particles quickly became transparent and allowed light to freely move through it, some of that light is now arriving at earth. The appearance of this CMB can give us information about how the universe formed. A Theory of Everything should be able to explain certain features of the CMB, and so we can indirectly check the validity of the theory. There may be certain predictions of any Theory of Everything that cannot be directly verified, however, I think many aspects of a TOE will have certain consequences for the evolution of the universe which can give indirect evidence for the validity of the theory. But, as always, I reserve the right to change my mind in the future…

Another interesting hypothetical Bee asked about was the following: Suppose there are two TOEs. Up to the limits of what we can measure, they both seem to be valid, but fundamentally they paint a very different picture of our universe. A silly example would be: Two theories, both unify the four forces and describe all particles and the CMB and all that. But one of them is based on the fact that the universe is made of chocolate, and the other is based on the fact that the universe is made of cheese. How would we know whether or not the universe is made of chocolate or cheese? I think that if both theories accurately described the observations we made of the world around us then, from a scientific standpoint, it really wouldn’t matter what was really going on. In this scenario, thinking that the universe is made of chocolate as opposed to cheese would not impact scientifically, it would only impact socially. It would surely be an interesting question, and I think peoples’ world views would differ greatly between the two ideas, but the science would not. For this reason I think it would be a time to leave the question up to philosophers to answer, at least until we found a discrepancy between our scientific observations and one of the theories. We could certainly assume that the universe is made of chocolate to help give us a decisive picture of the world in which we live. But the beauty of science is that at any point if something smells fishy, we can change our theory to better describe the world.

As for the question as to whether or not this is likely to happen, I don’t know. I don’t really think I have a good enough feel for the field yet to make a worthy guess. What I do know is that although it may sometimes appear otherwise, the world is full of clever people and (if we find a way to stop global warming) clever people will continue to be born. Science is historically a field known for its surprises. As (i think) Richard Feynman once said: Major scientific discoveries are very seldom followed by the cry of “Eurika!“. More often than not, they are followed by: “Huh. That’s odd…“.