You are currently browsing the daily archive for November 16th, 2007.
The Grand Unified Theory (GUT) has been sought after for years. Einstein died pursuing it. Many great minds have tried to tackle it and complicated theories and first steps abound. There are four forces in our universe: the electromagnetic force, the strong nuclear force, the weak nuclear force, and gravity. The Standard Model unifies the first three. The problem has been unifying these with gravity. String theory was proposed to account for gravity but so far it has been completely untestable. This, of course, invalidates it as a scientific theory. It has remained compelling to many physicists, though, in hopes of one day being able to test it. The goal of a GUT (or a theory of everything) is to reduce all of these forces to a standard set of equations.
At the moment, we have two theories which account for everything and no way to bring them together. The Standard Model and Einstein’s General relativitiy. Enter Garrett Lisi. He got his PhD from UC San Diego in 1999 and has since been unaffiliated with an academic department. He surfs and snowboards and basically goes around not knowing where he is going to stay next month or how he will pay for it.
E8 (right) is the key. It is a complicated mathematical construct that I don’t really understand from my glance at the wikipedia entry. As is typical in higher math, you have to understand 20 other things first and I’ve never even heard of Lie algebras. However, the layman’s breakdown is that it is an 8-dimensional pattern that encapsulates the symmetries of a 57-dimensional object which itself has 248 dimensions [source]. Make sense? Anyhow, apparently this thing was only well understood this year, despite being discovered over a hundred years ago.
So Garrett Lisi recognized that each of the 248 points in E8 correspond to the various elementary particles and forces in our universe. This left 20 points that had to be filled in with theoretical particles. So now all Garrett has to do is develop a set of experiments to test his theory. The Large Hadron Collider will go online next year and if string theory is correct, probably end the world. However, if Garrett is correct, we’ll all be alive in 2009.
This weekend will be the peak time for the Leonid meteor shower. It is so-named because the meteors originate from the section of the sky corresponding to the constellation Leo. The most locateable star in Leo is Regulus, which rises these days just after midnight on the eastern horizon. A little while later, Saturn rises behind it. Saturn and Regulus are both fairly bright so they make an easy pair to spot. The sky map below is from a perspective of Pittsburgh, PA at 1:51 am tonight (November 17, 2007). Peak time for the shower will be around 4am tonight and tomorrow night. [source]
Of course, you don’t have to find the constellation Leo in order to enjoy the Leonids. The comet Tempel-Tuttle leaves a trail of dust as it orbits the sun and occasionally we stray right into it. In 1833, the event was so huge people from Europe and North America took note of it. Estimates of the storm activity put it at over 200,000 meteors per hour! I dream of such a thing. It even led to the song “Stars Fell on Alabama.” Another big storm occurred in 1866 and again in 1966. Unfortunately, it looks like this year will be a modest viewing year, which puts the Leonids lower on the totem pole than the Perseids, which occur back in early August.
Viewing conditions for Pittsburgh look grim, which is typical of this time of year. This morning we had our first real snow. It had snowed a week or two ago briefly, but that was more of a snowy drizzle/wintry mix. Today there was actually accumulation on the dead leaves in the yard and on some cars. Nothing major yet.
