… and it feels so good
Per my previous observation, this phenomenon has now been properly represented.
more music charts
Monthly Archives: November 2008
Splitter
A physics-based puzzle game in which you have to guide your character to the goal by cutting wooden objects and joints.
Dude, It's Physics
The Physics of Surfing (Part One: Dropping In)
[P]addling by itself doesn’t get you into the wave, because you actually cannot paddle as fast as the wave is moving, and you need to match the speed of the wave if you want to ride with it. In order to catch up to that wave speed, it’s necessary to use the gravitational potential energy of the wave. The trick is to obtain sufficient speed by paddling that, as the wave travels under you, your board begins to fall down the face. As you drop down the front of the wave, the gravitational potential energy you gain is converted into kinetic energy. Soon you are travelling as fast as the wave. In fact, if you continue to drop to the bottom of the wave, you’ll be moving faster than the wave — and if you don’t cut into the face, you might temporarily outrun it.
Say "Cheese"
Ultrafast Lasers Show Snapshot Of Electrons In Action
In a paper to appear in the Oct. 30 issue of Science Express, the online version of the journal Science, the CU team describes how they shot a molecule of dinitrogen tetraoxide, or N2O4, with a short burst of laser light to induce very large oscillations within the molecule. They then used a second laser to produce an X-ray, which was used to map the electron energy levels of the molecule, and most importantly, to understand how these electron energy levels rearrange as the molecule changes its shape, according to Kapteyn.
1/Problem
Optics basics: Inverse problems at Skulls in the Stars.
Plenty of other techniques exist for measuring the internal structure of objects, using a variety of different types of waves. Magnetic resonance imaging (MRI) subjects a patient to an intense magnetic field, and makes an image by measuring the radio waves emitted when the field is suddenly switched. Ultrasound imaging uses ultrasonic waves to probe the soft tissues of the human body, and is used in mammography.
Each of these techniques is quite different in its range of application, but all require nontrivial mathematical techniques to reconstruct an image from the raw scattered wave data. These mathematical techniques are broadly grouped into a class of problems known as inverse problems, and I thought it would be worth an optics basics post to discuss inverse problems, their common features, and the challenges in solving them.
Knot Too Shabby
One of the reasons knots have given mathematicians fits is that the same knot can appear in very different guises. Tug here, tug there, and soon a knot will become unrecognizable, but remain fundamentally unchanged. To allow a knotted string to wiggle around without danger of untying, mathematicians seal its two ends together, making it a knotted circle. The first question mathematicians have to answer is simply, when are two knots really, secretly the same?
The dream is to create a sort of machine: Send in one of these looped knots, and out pops some result that would be the same regardless of the particular configuration of the knot. Because the answer wouldn’t vary with the arrangement of the knot, such a machine is called a “knot invariant.” And indeed, in 1927, mathematician J.W. Alexander created just such a “machine,” a method that produces a polynomial (an expression like 3×2 + 4x + 1) from any knot. The good news is that Alexander’s method always gives the same polynomial for a particular knot, even if the knot has been wiggled around to look very different. The bad news is that it can also give the identical answer for knots that really are different. For example, the granny knot and the square knot have identical Alexander polynomials.
Grab Your ACME Umbrella
Space station trash plunging to Earth
NASA and the U.S. Space Surveillance Network are tracking the object — a 1,400-pound (635-kilogram) tank of toxic ammonia coolant thrown from the international space station — to make sure it does not endanger people on Earth. Exactly where the tank will inevitably fall is currently unknown, though it is expected to re-enter Earth’s atmosphere Sunday afternoon or later that evening, NASA officials said.
The umbrella won’t help, of course. Just ask Wile E. Coyote.
Video the Vote
I’m on a mailing list for a singer/activist named Dana Lyons (it’s more for the singing part than the activist part); Dana’s family moved to Niskayuna sometime in the 70’s and he and I were in the Boy Scouts together for several years. He popped back up onto my radar screen when he released “Cows With Guns,” a spoofy little song about resisting the man. Dana was in Washington state and I was living in Vancouver, so the song got a lot of airtime, and when I spotted the CD at the music store and saw his picture on the back I confirmed that it was the same Dana Lyons.
Anyway, here is an excerpt from the email I received, explaining an activity about which I had not previously heard: video the vote.
———————————
My Fellow Americans
It’s Time to Wake Up and Smell the Corruption
In Our Voting Booths
Democracy is Fragile: Educate Thyself:
Robert F. Kennedy Jr. and Greg Palast’s article in the current
Rolling Stone: Block the Vote
http://www.rollingstone.com/politics/story/23638322/block_the_vote
(10-minute read, free)
Bill Moyers Journal on Voter Protections
http://www.pbs.org/moyers/journal/10172008/watch3.html
(15-minute watch, free)
“Free For All” Election Documentary
Watch entertaining and well-done free documentary about election
irregularities:
www.freeforall.tv
(80 minutes with popcorn)
Howdy Friends and Family,
I have two great adventures coming up. One which I wish I didn’t feel
it necessary to do and one which is the adventure of a lifetime.
Yes, traveling to Ohio in November is always on the top of everyone’s
vacation list, and I’m heading there next week. I’m traveling to
Columbus, OH to take part in Video the Vote, a movement of citizens
who are concerned about election irregularities across the United
States.
VIDEO THE VOTE
It’s pretty easy. I signed up as a volunteer videographer on the
website. On election day, if they receive reports of election
irregularities (malfunctioning voting machines, ridiculous lines,
harassment, etc.), they’ll give me a call and I will head out and film
it. Then I upload the video to youtube (via videothevote.org) and
voila, the situation is documented immediately. Thousands of folks
will be videoing the vote across the US. Can you help out? They need
volunteers in all 50 states.
I know some of you may think this sounds a bit like a conspiracy
theory (how could any of the nice people like Karl Rove even think of
tampering with an election?!), so I encourage you to read Kennedy’s
article and watch the vid and Bill Moyers and decide for yourself.
For me, this isn’t just about defending democracy: It’s about my own
integrity when I speak to children in schools about working to protect
the environment in our democratic system. I have a steadfast rule when
performing at schools: I don’t lie to children. And I’m not going to
take part in upholding a facade of democracy, making believe
everything is okay, when I’ve seen enough evidence that there is
serious corruption in our election system.
I Don't Know Much About Art, But I Know What's Neat
See how Emmanuel Guibert created the art for his graphic novel ALAN’S WAR