Sphere: Related Content
Surfer-Physicist's Unified Theory
Freelance physicist A. Garrett Lisi made headlines last year when he published his "Exceptionally Simple Theory of Everything" to an online wiki. The theory purports to be a blueprint of the universe, showing how all of the particles and forces of the universe are connected.
Lisi, who is speaking at the TED conference in Monterey, California this week, rejects string theory -- currently the dominant model of the universe. Instead, his unification theory places all known particles and the four fundamental forces of nature (electromagnetic, the strong force, the weak force and gravity) onto an exceptionally complex 248-point mathematical model known as E8 that was formulated in the late 19th century. Lisi's schema uses 228 points of the model, with 20 points left over for what he predicts will belong to 20 as-yet-undiscovered particles.
Lisi left academia after obtaining his Ph.D. in 1999, and since then has been working odd jobs to support himself while spending the rest of his time working on physics, surfing and snowboarding.
Lisi: The way gravity fits came from recent research in the Quantum Gravity community. This research provided a framework in which gravity could be treated as one of the other three forces, while still agreeing with Einstein's general relativity. When this was combined with a description of the Higgs field, it all fell into place perfectly. I was shocked to see it work so well; but that shock quickly diffused into excitement, which then congealed into a physics paper.
Lisi: These suggested particles are not so mysterious -- they would be a lot like the Higgs particle, but with color charges that keep them in bound states. I haven't yet solved the problems required to predict their masses, but they would still be recognizable if detected. Of course, if a bunch of particles are detected that are clearly not any of these 20, then this theory is in trouble. And if the Large Hadron Collider (scheduled to go online later this year in Switzerland) finds superparticles or other evidence for strings, I'm going to have to pay out some bets.
Lisi: Sure, I've made all my physics open source, and documented it as well as possible. I've got a personal wiki, Deferential Geometry,( <------<<<< )where I work on ideas out in the open. Many people have taken ideas from my work and run with them, to advance their own, which is good to see. The biggest help with the theory that I've received from others has been from mathematicians, who have provided answers to some of the trickier aspects of E8 group theory. And there has been practical help as well: friends who have offered me places to stay, or donated support, and there's even a surfboard shaper making me a new board -- from 42 Surfboards.
Wired: You said recently: "Since E8 is perhaps the most beautiful structure in mathematics, it is very satisfying that nature appears to have chosen this geometry." Did nature have a choice? Could the E8 framework be the result of an evolutionary process of trial and error that adapted until the universe got it right or do you think that beautiful structure was "ready made"? I guess the equivalent philosophical question for this would be, which came first -- the mathematics or the forces?
Lisi: This is a very unusual aspect of this theory. The largest simple exceptional Lie group, E8, is a unique structure in mathematics. If this structure turns out to be fundamental to how the universe works, then it seems to indicate our universe is not one that exists in a landscape of other possibilities. It would mean our universe is exceptional, and perhaps singular. Of course, it is philosophically questionable to consider other universes to begin with, since we're only aware of one. But, whether this theory works perfectly or not, it is undoubtedly true that the fundamental nature of our universe can be described by mathematics.
Guy is a show off, he got the formula for the Universe, a working wiki all on one page!
NO BODY should be that organized.
Wednesday, February 27, 2008
Tuesday, February 19, 2008
A 2,000-year-old mechanical computer salvaged from a Roman shipwreck has astounded scientists who have finally unravelled the secrets of how the sophisticated device works.
The machine was lost among cargo in 65BC when the ship carrying it sank in 42m of water off the coast of the Greek island of Antikythera. By chance, in 1900, a sponge diver called Elias Stadiatos discovered the wreck and recovered statues and other artifacts from the site.
The machine first came to light when an archaeologist working on the recovered objects noticed that a lump of rock had a gear wheel embedded in it. Closer inspection of material brought up from the stricken ship subsequently revealed 80 pieces of gear wheels, dials, clock-like hands and a wooden and bronze casing bearing ancient Greek inscriptions.
Since its discovery, scientists have been trying to reconstruct the device, which is now known to be an astronomical calendar capable of tracking with remarkable precision the position of the sun, several heavenly bodies and the phases of the moon. Experts believe it to be the earliest-known device to use gear wheels and by far the most sophisticated object to be found from the ancient and medieval periods.
Using modern computer x-ray tomography and high resolution surface scanning, a team led by Mike Edmunds and Tony Freeth at Cardiff University peered inside fragments of the crust-encased mechanism and read the faintest inscriptions that once covered the outer casing of the machine. Detailed imaging of the mechanism suggests it dates back to 150-100 BC and had 37 gear wheels enabling it to follow the movements of the moon and the sun through the zodiac, predict eclipses and even recreate the irregular orbit of the moon. The motion, known as the first lunar anomaly, was developed by the astronomer Hipparcus of Rhodes in the 2nd century BC, and he may have been consulted in the machine's construction, the scientists speculate.
Remarkably, scans showed the device uses a differential gear, which was previously believed to have been invented in the 16th century. The level of miniaturisation and complexity of its parts is comparable to that of 18th century clocks.
Some researchers believe the machine, known as the Antikythera Mechanism, may have been among other treasure looted from Rhodes that was en route to Rome for a celebration staged by Julius Caesar.
One of the remaining mysteries is why the Greek technology invented for the machine seemed to disappear. No other civilisation is believed to have created anything as complex for another 1,000 years. One explanation could be that bronze was often recycled in the period the device was made, so many artefacts from that time have long ago been melted down and erased from the archaelogical record. The fateful sinking of the ship carrying the Antikythera Mechanism may have inadvertently preserved it. "This device is extraordinary, the only thing of its kind," said Professor Edmunds. "The astronomy is exactly right ... in terms of historic and scarcity value, I have to regard this mechanism as being more valuable than the Mona Lisa." The research, which appears in the journal Nature today, was carried out with scientists at the National Archaeological Museum of Athens where the mechanism is held and the universities of Athens and Thessaloniki.Sphere: Related Content