This and That

With the weekend approaching, here's some distractions to kill your remaining working hours till 5pm:

• A very nice applet that zooms you through the scales of the universe, all the way down to the Planck length.


• An interesting recollection by Robert Weisbrot of Edward Witten's way to physics:
  
  "I am reminded of a friend from the early 1970s, Edward Witten. I liked Ed, but felt sorry for him, too, because, for all his potential, he lacked focus. He had been a history major in college, and a linguistics minor. On graduating, though, he concluded that, as rewarding as these fields had been, he was not really cut out to make a living at them. He decided that what he was really meant to do was study economics. And so, he applied to graduate school, and was accepted at the University of Wisconsin. And, after only a semester, he dropped out of the program. Not for him. So, history was out; linguistics, out; economics, out. What to do? This was a time of widespread political activism, and Ed became an aide to Senator George McGovern, then running for the presidency on an anti-war platform. He also wrote articles for political journals like the Nation and the New Republic. After some months, Ed realized that politics was not for him, because, in his words, it demanded qualities he did not have, foremost among them common sense. All right, then: history, linguistics, economics, politics, were all out as career choices. What to do? Ed suddenly realized that he was really suited to study mathematics. So he applied to graduate school, and was accepted at Princeton. I met him midway through his first year there--just after he had dropped out of the mathematics department. He realized, he said, that what he was really meant to do was study physics; he applied to the physics department, and was accepted.
  
  I was happy for him. But I lamented all the false starts he had made, and how his career opportunities appeared to be passing him by. Many years later, in 1987, I was reading the New York Times magazine and saw a full-page picture akin to a mug shot, of a thin man with a large head staring out of thick glasses. It was Ed Witten! I was stunned. What was he doing in the Times magazine? Well, he was being profiled as the Einstein of his age, a pioneer of a revolution in physics called "String Theory." Colleagues at Harvard and Princeton, who marvelled at his use of bizarre mathematics to solve physics problems, claimed that his ideas, popularly called a "theory of everything," might at last explain the origins and nature of the cosmos. Ed said modestly of his theories that it was really much easier to solve problems when you analyzed them in at least ten dimensions. Perhaps. Much clearer to me was an observation Ed made that appeared near the end of this article: every one of us has talent; the great challenge in life is finding an outlet to express it. I thought, he has truly earned the right to say that. And I realized that, for all my earlier concerns that he had squandered his time, in fact his entire career path--the ventures in history, linguistics, economics, politics, math, as well as physics--had been rewarding: a time of hard work, self-discovery, and new insight into his potential based on growing experience."
  
  [Via Michael Nielsen, via Hacker News. Read the full speech here.]


• You might already have read it on Nature News: Astronomers have found the to date most massive neutron star with about 2 solar masses. When I read this, a bell was ringing faintly in the dusty back of my head. Meanwhile I've figured out what was ringing: Smolin's Cosmological Natural Selection predicts an upper mass limit for neutron stars of 1.6 solar masses. (See hep-th/0612185, section 3.2).


• Some months ago I was sent a link to an April fools day paper, funny-haha, physicists style. That paper has now resurfaced on my desk: Schrödinger's Cat is not Alone. It's a humorous take on the interpretation of quantum mechanics and cat dynamics. Not the sort of humor that deepens my laugh wrinkles, but I thought some of you might find it amusing.


• Here's something that did give me a good laugh. Real life absurdity:
  Nurses find the weirdest stuff. [Via Bora].

I wish you all a nice weekend!