Category Archives: science

Less In The Dark Than Before?

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From NASA, tomorrow, at 1:00pm EST: An announcement about Dark Energy. If the pattern of last time is to be followed, there must be new evidence from the space telescope team (represented by Riess and Livio at the press conference) in favour of one interpretation or another. Since they are saying that they will “announce the discovery that dark energy has been an ever-present constituent of space for most of the universe’s history”, I imagine that means that there is stronger evidence than before for Dark Energy being a cosmological constant. […] Click to continue reading this post →

Out of Step, Out of Arguments and Out of Time

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Those are the words of Kofi Annan at the UN conference on Climate Change earlier today (see AP story by Charles Hanley). His speech emphasized the “frightening lack of leadership” in forming strategies for how to tackle the huge task that lies ahead for our planet with regards emissions. Getting … Click to continue reading this post →

When Chaos Goes Quantum

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Mark SrednickiNot many Mondays ago we had a colloquium entitled “Quantum Chaos and the Foundations of Statistical Mechanics”, by Mark Srednicki, of UCSB.

This was a double treat for me, since I’ve known Mark since my days in Santa Barbara, and remember many happy lunchtimes sitting at lunch with him overlooking the lagoon talking about everything from physics to Bablyon 5. That was during those truly amazing days of being a postdoc in string theory at the time when D-brane technology was turning the field upside down, and a lot of the torque needed for this was being generated right there in Santa Barbara, sometimes in lunchtime conversations. I was reminiscing about those days just a week before in Cambridge, having run into Karl Landsteiner and Roberto Emparan, two other postdocs from those fantastic times. The reason for us all being in Cambridge was to attend the Andrew Chamblin memorial conference, which I told you about in an earlier post. Andrew was also a postdoc there, around the same time as us, and we rapidly forged the good friendships that you’ve read about in a number of earlier posts linked from the previous link.

Mark used to tell me a bit about Quantum Chaos back then too, and I found it interesting, but always wanted to hear the story laid out properly, and to hear what he […] Click to continue reading this post →

Better To Burn Out, Or To Fade Away?

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On the site Space.com, I found a nice article by David Powell about the Cassini spacecraft’s future. (Cassini has done some wonderful work recently, including bringing us wonderful images such as the one below of Titan and Epimetheus, and Saturn’s rings.)

[image]

Cassini’s NASA handlers are wondering about what they will do with it when its mission is over. Here are some of the options they are considering:

[…] Click to continue reading this post →

The 2006 Nobel Prizes: Who, What and Why!

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Not long after the colloquium on the Fields Medal work, we had a joint presentation by three colloquium speakers on the topics of the three science prizes awarded from the good folks in Stockholm this year. This was another very popular Monday talk, with people from various other departments joining us, given the topics being discussed. The speakers talked about the science of the prizes, and also reflected upon how it drives or interfaces with future research, perhaps their own research program.

First up was Lin Chen, of Chemistry and Molecular and Computational Biology. He told us about the Chemistry prize, awarded to Roger Kornberg, “for his studies of the molecular basis of eukaryotic transcription”.

Starting out by reminding us about the basic chain of relationships within organisms concerning the movement of genetic information, (the “Central Dogma”) he explained […] Click to continue reading this post →

More Scenes From the Storm in a Teacup, VI

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A quick update:

* There was a second installment of the discussion led by George Johnson about press coverage of string theory. He went back to look to see what exactly some of those early articles said… How much coverage was there to start with? When did it start? When did it begin get out of hand? Did it get out of hand? Is this all just part of a standard bubble that happens for any field that the press decides to cover, a sort of manufactured (my word not his) boom and bust cycle? All issues that were touched upon in the discussion. Note also that the discussion broadens out considerably -as it should, (finally!)- to talk about the broader issue of coverage of topics in physics and science in general. The positive and negative effects of press coverage on attracting the next generation of students was also discussed. The discussion (this aspect in particular) was especially interesting because of the remarks by a number of senior people in the audience who were able to talk about their experiences over the years having seen the cycles recruitment of students in their own departments. Worth a listen/look at the archive here.
* Lee Smolin has written a “Dear Friends” letter in response to some of the things that have been pointed out about his book, and about other points he’s made publicly in various discussions. He’s given over some time to write quite a bit, which in general is a good thing to have done. You can find it here.

I’ll leave it to you to form your own opinion about Smolin’s remarks (I’ve not had time to read it in detail yet), and start a discussion here. Maybe ask him some followup questions here, for example. To help with context and build a more complete picture, do read some of the earlier comments and discussions involving him -and questions put directly to him- on the threads that share the name of this post. (e.g., Here and here.) Put those alongside the discussion with Peter Woit and of the central thesis of Woit’s book too. They are inseparable.

My set of opinions on the issue is the same as it was before. Even though I’ve said it all so many times here, since blogs seem to have no memory, I will summarize a bit:

[…] Click to continue reading this post →

Mercury Passing

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transit of mercury

So did you see yesterday’s event? (Above is a snapshot of a movie of the event from a SOHO image capture sequence. Mercury is a tiny dot just below the structure on the right that is not far from one of the remarkably few sunspots on the sun at present (it is low season for them). Go there for more images to see Mercury in action.)

Joe Vandiver (centre, below) here at USC had a telescope set up for all on campus to view: […] Click to continue reading this post →

Elemental

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Yesterday in Physics 100 we started a discussion of the structure of matter. This inevitably brings up the early ideas from 400 BC about atoms, from Democritus (and others) at least in the Greek line of thought. These ideas were later brushed aside by Aristotle who declared that the elements from which everything can be constructed were Earth, Air, Fire, and Water.

Of course, one is obliged to show a slide at this point. I could not resist this one: […] Click to continue reading this post →

A Man Out Standing In His Field

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Two of our colloquia this semester were concerned with work very much in the public eye this year. The first was from Francis Bonahan of the Mathematics Department here at USC.

F bonahan colloquium

He talked about the work that won the Fields medal – the proof, by Grigori Perelman, of the Poincaré conjecture. Or better, I should say the work toward the proof, since the citation does not explicitly mention the conjecture, but his larger body of work. (MathWorld link, Wikipedia link.) In fact, Francis spoke about a lot more than just the Poincaré conjecture. He talked about the larger setting in which that work fits, something mathematicians call the “geometrization conjecture”, which Mathematicians care a lot more about. Perelman’s work does more than just prove the Poincaré, it addresses the whole (3-)ball of wax, so to speak. He told us quite a bit about that in the talk, spending most time talking about what they were and how they fit into the scheme of things, rather than […] Click to continue reading this post →

Twelve Days of Physics

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This morning I received an email from someone called “Grrrl Einstein” today which read:

I am creating a Physics Calendar for the Holiday season, and I am including twelve entities. So far I have:

  1. Newton’s Laws
  2. The Dirac equation/Schrodinger equation
  3. The Clifford Algebra defining the Dirac gamma matrices
  4. E=mc2/Einstein’s equations/postulates and/or some solution of them, such as the Schwarzschild solution
  5. The principle of least action
  6. Maxwell’s equations
  7. E=hv
  8. The Yang-Mills Lagrangian
  9. The Schwinger-Dyson equations or something else related to functional methods
  10. Stokes’ Theorem
  11. Entropy

What would be a good String Theory equation to round it out? Any things I should include/exclude?

She also says: […] Click to continue reading this post →