Ultima Thule

In ancient times the northernmost region of the habitable world - hence, any distant, unknown or mysterious land.

Saturday, July 15, 2006

Physics Awaits New Options as Standard Model Idles

By Aussiegirl

This beautiful illustration is of the particles that make up the standard model -- how marvelous the brilliance of the minds that can look at our pleasant world, full of all sorts of objects that seem so completely different from each other, and, by force of inspired imagination and intuition and hard mental work, arrive at such a stunning portrait of our wonderful universe!
So, everything that we see has structure -- but is itself ultimately made up of these "pointlike somethings" that themselves have no structure. It's all an illusion -- as Gertrude Stein wrote, there is no there there. And even worse, it turns out that our observing the universe collapses the quantum wave function into what we observe. It looks like we the observer bring the universe into existence -- the observer becomes the observed.
(Here's a link to a later article in which Overbye answers selected questions from readers about this essay.)
Physics Awaits New Options as Standard Model Idles - New York Times
Physics Awaits New Options as Standard Model Idles

For most of us, any physics is new physics. Having stopped paying attention somewhere back around "for every action there is an equal and opposite reaction" or the discovery that you can make sparks by shuffling your feet on the carpet and then touching a doorknob (or another person), we amateurs respond with the same glazed mixture of wonder and incredulity to the latest abilities of computer chips or the expansion of the universe.

For us, the world is constant naïve novelty. The same cannot be said for professional physicists, the ultimate insiders.

Forget the lifetime tenure, the travel, the six-figure book contracts — what professional physicists live for is the tsunami moment when they know something that nobody else has ever known, the revelatory flash of a new glimpse into the workings of what Stephen Hawking, the Cambridge University cosmologist, called "the Mind of God."

Alas, God, as reflected in the known laws of physics, hasn't gotten any smarter since the 1970's. It was then that particle physicists put the finishing touches on the Standard Model, a collection of theories describing all the physical forces except gravity.

They have been stuck in that model, like birds in a gilded cage, ever since. The Standard Model agrees with every experiment that has been performed since. But it doesn't say anything about the most familiar force of all, gravity. Nor does it explain why the universe is matter instead of antimatter, or why we believe there are such things as space and time. [...]

Physicists have high hopes that some new physics will begin to reveal itself when they fire up the world's largest particle accelerator, the Large Hadron Collider at CERN outside Geneva in November next year, although the laboratory just announced that the accelerator would not be running at full strength, colliding protons with seven trillion electron volts of energy, until 2008.

If the physicists are lucky, in addition to the last piece of the Standard Model, a character known as the Higgs boson, new particles not produced since the Big Bang could eventually come spitting out. [....]

Unlike, say, in the tax code, however, in physics new laws are more elegant and economical than the ones they replace. For the last century they have usually involved new symmetries that nature seems sworn to uphold — things that don't change when we view the universe from different perspectives.

Physicists have one more symmetry card to play, a concept known as supersymmetry. If this notion is right, there is a whole new population of particles, so-called superpartners to the ones we already know and puzzle about waiting to be discovered.

The problem is that according to some versions of supersymmetry, the effects of these particles, if not the particles themselves, should already be showing up in delicate experiments like the flip-flopping meson. There are thousands of versions of supersymmetry, but the fact that nothing has shown up yet has caused "a growing tension in the field," said Nima Arkani-Hamed, a particle theorist at Harvard. [....]

Meanwhile, something bizarre really has shown up. It just hasn't been in a form that physicists can test and play with. Eight years ago two teams of astronomers discovered that the expansion of the universe was speeding up, in defiance of cosmic gravity and of what might be left of common sense. The universe apparently is its own antigravity machine.

That might be weird enough, and deserving of tabloid headlines, except it apparently happened before. New studies reported last spring of relic radio waves left over from the waning days of the Big Bang have reinforced, but not yet conclusively proved, the idea that a violent antigravitational force known colloquially as inflation held sway in the first moments of time, stretching and bubbling the cosmos into roughly the shape we see today.

Whatever bubbled and stretched the cosmos is beyond the ken of the Standard Model. Inflation is new physics, Sean Carroll of the University of Chicago explained in a recent e-mail message, adding, "Anything other than inflation would be even newer physics!" [....]

Some theorists think they have an answer, namely that the world is made up of tiny vibrating strings. As of now, however, there is scant evidence other than the beauty of their equations that the string theorists are right. [....]


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