Category Archives: science

Bigger than the FCC

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We’ve been studying rotating black holes in my class this week, which has been fun. We get to apply the techniques we’ve been honing in the context of the Schwarzschild solution (link to recent posts below) to a bit more complicated solution, the Kerr solution, which includes rotation. Some equations follow, although you needn’t be put off by them. Most of this will make sense without really understanding them much. Just so you can see the shape of the things we scribble, I’ll show you the equation that captures this curved spacetime geometry, with no real explanation (sorry):

kerr solution

Here [tex]\Delta\equiv r^2-2Mr+a^2[/tex] and [tex]\rho^2\equiv r^2+a^2\cos^2\theta\ .[/tex] The parameter [tex]a[/tex] is the ratio of the solution’s spin or angular momentum [tex]J[/tex] to its total mass [tex]M[/tex], measured in appropriate units. It’s a very important solution to get to grips with, since it’s not just fantasy physics, but highly relevant for astrophysics since black holes that are “out there” are unlikely to be non-rotating, and in fact, one can expect them to be rotating at quite a clip in many cases. A good many black holes – including some of the […] Click to continue reading this post →

Sand, Man

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sand dune from 2006 trip to Death ValleyIn physics, most of what we do is look for the simple, often in extremely complicated systems. If you’re asking the wrong question, or looking at the wrong aspect of the system, this quest for the simple is unlikely to work at all, but the right question asked about the right aspect can yield rather striking insights, often with far-reaching consequences. Although it often is not emphasized in this manner during our school or undergraduate (and sometimes even graduate) education, this is the primary skill in the physicist’s arsenal that we teach and learn. (See an earlier article here for a take on this.)

Sometimes, you don’t need the sharp eyes and years of training and drilling in these seemingly arcane (but, I’d argue, most natural) arts (and the requisite sequestering away in monasteries and nunneries with abstinence, self-flagellation, and so forth) – there are times when if just jumps out at you that there’s a simple question or two […] Click to continue reading this post →

Lighting Up Field Theory

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Sidney Coleman lecturingI got an email from one of the group’s graduate students today*, pointing to an archive of videos of lectures by the great Sidney Coleman. He’s doing quantum field theory. This makes this a marvelous resource, in principle, and so I thought I’d share them with you. They are here.

I wonder: are these the lectures that Jacques Distler has mentioned attending a few times in the past on his blog? This was the 1975-1976 year, a graduate course. I wonder if anyone (else) I know was in that class room…

[Update: I learned from the discussion over on Jonathan Shock’s site that there are some partial lecture notes from the course here, by Bryan Gin-ge Chen, based on notes by Brian Hill. He’s looking for help on completing the project, so get in touch if you want to help out..]

I’ve never seen Coleman in action before, and so I was immediately rather curious, […] Click to continue reading this post →

Biggest Binoculars Ever

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Large Binocular Telescope (image courtesy of the LBT)

Am I the only one who sees this, or does this look like the head of some giant friendly robot, all smiles with big cheeks? Remember Brad Bird’s Iron Giant, for example?

Well, it is actually not from science fiction but science fact. And it is a robot, sort of – well it can be controlled remotely to swivel its head and so forth. It is actually a […] Click to continue reading this post →

Festival of Books

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LA Times Festival of Books ImageIt’s a bit more than a month away. It’s always fun every year. It’s a Los Angeles celebration of the written word, done in wonderful sunshine, with hundreds of marvellous events in three days for young and old – Yes, it is the LA Times Festival of Books, coming up the weekend starting April 25th. The main daytime proceedings take place on the 26th and 27th (Saturday and Sunday) and I recommend them to you if you’ve not been. Mark your calendar. (Once you’re over there on Sunday, stay for the Categorically Not! event in the evening (entitled “Loops”), which will involve among others, science writer Dava Sobel!!) (Above right: One of the 2008 theme images from the Festival’s website. More here.)

The Friday evening will see the book prizes given out, kicking off the festival as usual. I remembered this just now because I found myself curious about the shortlist of books in the Science and Technology category. I wondered if there was something on […] Click to continue reading this post →

Tales From The Industry XIX – Black Comedy

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Wow, a lot of time has passed since I thought I’d get around to posting about this. You’ll recall that I went to take part in the taping of a segment for Comedy Central some time ago, Well, later on I went to the taping of the full show in which it will appear, and it was an amusing and interesting experience.

Lewis Black on set of Root of All Evil

The show? Comedy Central, and in particular, Daily Show fans will be pleased to learn that Lewis Black finally has a shw of his own, and it is called “The Root of All Evil”. The format is that he presides as a judge over a case examining which of two popular […] Click to continue reading this post →

Tipping the Light Cone: Black Holes

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Black Holes by Tamsin Van Essen: http://www.vanessendesign.com/

Black Holes, by Tamsin Van Essen. Part of a series of lovely ceramics with a physics theme. For more, visit the websites here and here.

As you may recall from the post I did some time ago, the “Light Cone” is a rather important concept in physics, and keeping track of it in a given physical scenario is an extremely important tool and technique for understanding many physical situations. (I urge you to review that post before continuing reading this one.)

One way to understand a most important concept – the event horizon – is by keeping track of lightcones, and so let’s go ahead and explore that here. The outcome is that […] Click to continue reading this post →

Categorically Not! – Puzzles!

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The next Categorically Not! is on Sunday March 9th (upcoming). The Categorically Not! series of events that are held at the Santa Monica Art Studios, (with occasional exceptions). It’s a series – started and run by science writer K. C. Cole – of fun and informative conversations deliberately ignoring the traditional boundaries between art, science, humanities, and other subjects. I strongly encourage you to come to them if you’re in the area. Here is the website that describes past ones, and upcoming ones. See also the links at the end of the post for some announcements and descriptions (and even video) of previous events.

The theme this month is Puzzles! Here’s the description from K C Cole:

What isn’t a puzzle? The universe, life and everything are essentially puzzles that, to borrow from Einstein, “beckon like a liberation.” Designing buildings, choreographing dances, cooking meals and getting along with other people all involve solving puzzles (as, of course, does figuring out what’s right in front of your eyes—not to mention putting together a program such as Categorically Not!) A love of puzzles and the challenge of solving them is deeply embedded in human nature.

Categorically Not! - Puzzles! - Speakers

Gwen Roberts, Scott Kim, Gavin Scott.

Our March 9th Categorically Not! features puzzlemaster Scott Kim, who’s […] Click to continue reading this post →