The exo-planet hunting craft Kepler has found 1235 candidate planets orbiting other suns so far. The APOD site has a lovely composition by Jason Rowe showing representations of all of those suns with the spots on them that represent the planet transiting in front of them (that’s how they are found by Kepler). They are all nicely […] Click to continue reading this post
While on my way to work yesterday, I encountered an unusual sight (pictured on the right). It was a walking stick, leaning up against a post. It was unusual to me simply because I imagine that someone had lost their stick, and so someone else, upon finding it, had put it there in plain view so that the owner might find it again. Alternatively, the owner had simply forgotten it there? But surely you would not lose or forget and item you presumably depend upon for walking…? Either way, I’m finding it difficult to imagine a narrative leading to this circumstance that does not have slightly disturbing undertones to it. […] Click to continue reading this post
It was quite a busy week for me, and so all those moments I meant to stop and post thoughts and observations seemed to evaporate as I went from one thing to the next, with rather full days. I hit the ground running on Monday with several extra things on the calendar including being an external member of the committee for a thesis defense in the Chemistry department. Always useful and instructive to look in on what one’s colleagues are up to, and it was a rather nicely written thesis well defended.
The evening saw me at Bovard Auditorium to attend a pleasant visit by author Michael Ondaatje. My colleague from English and Comparative Literature, Hilary Schor, always super-enthusiastic about great authors, gave an introduction and then he came onto the stage and read a few extracts from his work before having a rather nice conversation with Hilary. Then the audience joined in with questions and comments of their own. While it was not full, it was a decent audience for this event, given its type, and I was happy to get the perfect seats I got. I had not done an RSVP, and came as a walk-in only to discover that some of the people on the door knew me and arranged for me to sit in the reserved seating for special guests. Only then did I remember that I’m on the committee that partly was responsible for this event […] Click to continue reading this post
One of the things I’ve noticed is that there’s not an awful lot of focus on pure drawing in the art world here in Los Angeles. I don’t see a lot of it up in galleries, on artwalks, on people’s walls, and so on and so forth. At least not in comparison to painting (especially) or sculpture. That may be a function of my ignorance, not having studied all the aspects of the “scene”. It may also be a more widespread phenomenon than just Los Angeles. Not sure. Anyway, when an exhibition with a drawing focus does come along, I get excited and often go. (The Getty had two big ones in the last couple of years, I should say, focusing on da Vinci (hurrah!) and Rembrandt (hurrah!) and his students on different occasions. But what about contemporary work?)
Well, to my delight I discovered that Saturday had an opening event at Gallery Nucleus with two major highlights for me. The first was that it was focusing on pencil drawing by current artists (Lined in Lead: Works in Graphite), and the second was that Michael Zulli would be there (there were some works of his on display) for the opening. I simply love his work in the graphic novel art world. I’ve no idea if you read […] Click to continue reading this post
Tomorrow’s full moon is going to be the closest to us in 18 years, apparently. It’s called a supermoon by some, and no doubt some will try to link it to many major events here on earth, both natural and man-made (if you’ll forgive the distinction). I won’t do a long post about this issue, but instead refer you to Phil, who is excellent on the science of this and related subjects.
What I will say instead is that all commentators seem to have missed that this is the best opportunity in years to gather moon-milk! Get out your ladders and buckets and go for it!
What am I talking about? At my last birthday I was given* a lovely collection of stories by Italo Calvino, and the first one is entitled “The Distance of the Moon”. It begins with a description of the fact that a long time ago the moon orbited much closer to the earth, as you may know, and then weaves a delightful story from there. The story involves reminiscences, by the narrator Qfwfq, about those good old days when the moon came so close that once a month (yes, I know) the earth’s inhabitants would take boats out onto the sea to the where the moon came close and climb up a ladder to its surface to gather the much-desired substance known as moon-milk. A lovely extract follows: […] Click to continue reading this post
It does look a bit like a coconut macaroon, and a particularly tasty one, but I must report that it is in fact an example of a Fremont pincushion (chaenactis fremontii), a white flower blooming in the deserts of the South West. I took this one in Death Valley yesterday. (It is Spring break, and I decided to get away for a bit.) Click for a larger view. There’s a tiny little creature of some sort perched on one of […] Click to continue reading this post
A scene from Saturday in Grand Hope Park downtown Los Angeles. Several of us turned out to sit, picnic, and chat about being pedestrian in LA. It was about building communities, connecting with people, getting around the city, development, the homeless, the artists, the businesses, restoration, preservation, and so on and so forth. See the site here. I knew about it because Linda Pollack of Habeas Lounge contacted me because she wanted me to come and share a bit about how I use public transport in combination with walking and cycling (and she wanted me to do a bit of show and tell with my Brompton folding bike (you can see it in the picture). […] Click to continue reading this post
A snap of some bathroom fittings (nickel finish) just before I installed them in a “new” bathroom, before my guests arrived in December. I rather liked the look of them all gathered there, on the simple background of tiles. I say “new” (in quotes) because the bathroom was actually finished way back in 2008. Procrastination… Yeah.
Somehow I’d never got around to finding the various fittings I wanted for it, partly […] Click to continue reading this post
It was a fun week in the string theory class this week, as we got to some major landmarks that are always fun to teach. We’ve uncovered the extended objects called D-branes (see numerous previous posts for how useful and important these objects are in string theory research) in all their glory in the lectures before, and deduced lots of their properties, such as the form of the action that determines how a D-brane moving in spacetime responds to the various fields (including the geometry) created by the string theory. That’s all fun, but then the key thing to do next is to compute the mass of these dynamical objects, or the mass per unit volume – the tension. Computing it fully, with no hand-wavy factors. Your mass measures how strongly you interact with gravity. So you can measure it by studying the gravitational interaction between masses. (You do that when you step on a scale to measure your weight… well the scale does it by showing how much force it takes to stop you from falling through the floor toward the center of the earth…)
So in class this is when we go all Polchinski and unpack the tension computation, stopping to admire the various features of string theory you learn along the way, and seeing how simply beautifully the various basic features of the superstring theories that we’ve met in the last few lectures encode themselves in one nice object – the vacuum amplitude [tex] {\cal A }[/tex] from the cylinder diagram representing either exchange of closed strings (including quanta like the graviton – this is what you focus on to learn what the mass is) between a pair of D-branes, or an open string with its ends tethered to a pair of D-branes going in a closed loop. That there are two ways of looking at the diagram, an open string way (running time around the cylinder) and a closed string way (running time along the cylinder) is a hugely powerful thing, and is at the heart of so very much of what we do in string theory these days especially – including a lot of what I’ve told you in previous posts (see e.g. here and here) about applications to things of interest in current experiments.
One of the fun things about all this is that the answer is actually [tex]{\cal A}=0[/tex]. It is zero because all the infinite modes of oscillation of the string gather themselves up nicely to give a factor:
[tex]
q^{-\frac{1}{6}}\prod_{n=1}^{\infty}(1+q^{n-\frac{1}{2}})^8-q^{-\frac{1}{6}}\prod_{n=1}^{\infty}(1-q^{n-\frac{1}{2}})^8-16q^{\frac{1}{3}}\prod_{n=1}^{\infty}(1+q^{n})^8=0\ .
[/tex]
Think of [tex]q[/tex] as a book-keeping device that lets one track energy contributions (in the power of it that appears in a term if one expanded this expression), and how many […] Click to continue reading this post
There are a lot of silly, ill-informed things said about Los Angeles, mostly in the form of lazy clichés. Sometimes said by people who are otherwise quite sensible, but the power and groove of a truism is hard to resist, even when it is an untrue one. One of them is that there are “no seasons” here. This is just a silly thing that people say in place of saying that they are used to seasons from a different climate and they have not taken the time to listen and watch for the march of the seasons that is evident here. (I think also that we have it amplified by popular culture that the standard symbols of the Spring, Summer, Autumn, Winter cycle involving snow and red and gold leaf colours and bare trees and jack frost nipping at your nose and so forth are “the way things are supposed to be”.) A friend of mine has in her email signature the slogan “I have a life. It is just different from yours”, and so I will retool it here: “We have seasons. They are just different from yours.”
Just like anywhere else, the seasons wink or call (sometimes even shout) at you through certain combinations of colours, smells, temperatures, and so on. I think people miss a lot of cues in Los Angeles because they don’t get out of their cars and walk the streets very much. Even a few gardens or hedgerows passed along the way can show a lot about the mood of the season the city is in. For me, colours and smells are very big cues in Los Angeles, and there are times when large parts of the city seem to be dominated by a single plant’s smell or colour or sometimes both. For me, it is the Jasmine time of year now. This is when the night-blooming jasmine bushes (cestrum nocturnum, apparently) of the city all seem to work in concert and fill the air with a great scent, and lovely clumps of creamy […] Click to continue reading this post
Here’s a sketch I did either in the airport or on the plane back from Morelia last June. Well, it was certainly finished on the plane, I think. You will recall that I was in Mexico to give some lectures on string theory at a quantum gravity school (see here and here and the related posts links below). As part of the practice and experimentation I was doing at the time (for The Project), I was drawing interesting faces, sometimes from photographs, like for this one. You just hold the photo in one hand (this one on the screen of my camera) and sketch it. I was working on a 8.5inx11in sketchpad with a charcoal pencil, I think. (I was trying to be quick, and I think it was about 15 or 20 minutes work.) The photo was taken a day or two before in the village of Pátzcuaro. I think I’d mentioned my visit there to you in an earlier post, but had showed you no images except some clocks.
Well, a funny/nice thing happened. The guy sitting next to me two seats over spoke […] Click to continue reading this post
