on the LIGO experiment

Usually, popular science “excitement” over scientific results tends to be overdone. A day of reflection on the publication of the gravitational waves detection (paper here) leads me to believe that this is really worthy of excitement, much more so than the ballyhooed Higgs boson detection a few years ago. Both are important, of course.

The reason is subtly put by the inimitable Brian Greene, near the end of the video.

(Read the article)

kendall band and stiff resonator physics

The Kendall Band at the subway station on campus had been rusting away, with only the chimes — the part they call “Pythagoras” — working. The other parts, “Kepler” and “Galileo” I have never seen working in all the years I have been here. Then one day “Pythagoras” too was gone for repairs. They posted this note for half a year until suddenly, it was back!

“Pythagoras” is two identical sets of eight pipes that could be struck by seven different mallets each. The mallets are controlled by a bar that could be swung back and forth by an attached handle which the user controls on the platform. Before the repairs, I had never paid attention to its intricacies, partly because there was not much time to play with them in the time before the next train arrived, and partly because the old rusty version didn’t make great sounds and I thought they were just some randomly sized pipes. Plus, the handle lacked fine control, and the best one could do was to hopefully transfer as much energy as possible to even get the thing going.

When it came back new, it was looking much like a real instrument and now I wondered what else you could do with it besides swinging the handle back and forth like most people do. Surely you could play an actual melody, right?
(Read the article)

what’s an application anyway

Stephen Boyd quips about a power allocation algorithm:

Oh by the way, this is used now, for example, in DSL and it’s used actually everywhere. Okay, and I’m not talking about used by …professors… I’m talking about, it’s used when you use DSL.

Sometimes engineers forget that to a mathematician, an “application” is another theoretical problem … only maybe in physics.

storing medicine in the refrigerator

It is said that you should store medicine in a cool, dry, and dark place. Then they say, don’t store it in a refrigerator, because “although it is cool, it is also humid.” I think this goes against basic physics. Yes, the refrigerator almost always has higher relative humdity than the room air, but in terms of absolute humidity of water vapor suspended in gas form in the air, it has to be lower. The rest of the water is in liquid form somewhere, like on the walls and lid, and those are water molecules that won’t be hitting the pills (unless they pool at the bottom, that is). In fact, people complain all the time about refrigerator air being too dry for their produce. So it seems the refrigerator is in fact an excellent place to store medicine.