Tuesday, July 26, 2011


Just read "Wicked: the Life and Times of the Wicked Witch of the West". This after we saw Wicked in London as part of our summer Europe trip. My cousin Christopher plays the drums and various other percussion pieces in that production.

The musical is a blast. We had great seats, the music and singing were fabulous, the staging sometimes overwhelming, the kids loved it, Chris showed us around a little bit... what fun.

When we got back, we got the music, and now the kids have mostly memorized all the songs. It's slightly disturbing seeing my 4 year old singing "No one mourns the wicked".

Martha got the book out of the library, and we both read it. Like all tragedies, it's frustrating. It's a vastly more complex and subtle story than the musical. If you're reading this but haven't read the book or seen the musical, see the musical first, as it'll be tough to enjoy after the book. And don't read the rest of this post.


Like most things that I really like, I wanted the book to be better. In particular, a good tragedy should make me feel the inertia of doom, the sense that the characters are carrying themselves towards their downfall. In the book, there was definitely some of that, but I also got the feeling that doom was coming in the form of spunky little Dorothy Gale, and that the characters were bending their wills to the needs of that other story arc. So that wasn't as impressive. And why the hell couldn't a smart girl like Elphaba convert the tactical (and unsuspected) advantage of being able to fly on a broom into a way to pick off the wizard and his chief lieutenants.

The part that I really liked was how Elphaba's desire to do good was a significant part of what drove her to her doom. I find myself strongly agreeing with the idea that the desire to do good is not good in itself, and can actually lead to evil. If you want to be good you have to actually *do* it.

But there were so many things to love about the book. The dialog, the political machinations, tictocism, Elphaba's reaction to Dorothy asking for the forgiveness that Elphaba herself had been denied... I love reading an author who has insights way past my own.

Thursday, February 17, 2011


Ed Lu gave a talk at Google today on his B612 foundation.

He mentioned that the asteroid that caused the K-T extinction was probably 10 miles in diameter, um hummm.... which meant that the top had not yet entered the bulk of the atmosphere when the bottom hit the ocean. That image really got me.

The speed of sound through granite is 5950 m/s, which is substantially less than the speed of an incoming asteroid. Things in low earth orbit go at about 7800 m/s, and Ed said incoming asteroids are around 3-4 times that. So that means that when the asteroid smacks into the earth, there is a really good chance that the back of the asteroid will hit the earth before the shock wave gets to it -- it'll punch all the way into the Earth surface. Koeberl and MacLeod have a nice table here which shows a granite on ice impact needs only 6 km/s vertical velocity to punch all the way in (they neglected water as a target material, an odd oversight since the majority of the earth is covered in water, more or less a solid at these velocities). If the incoming velocity is 25 km/s, which is on the low side of what Ed suggested, then anything striking within 76 degrees of vertical is going all the way in. It seems to me that most impacts would be like that.

So after the impact, most of the energy is added to stuff below the ground surface. That's 1e25 joules for the K-T asteroid. Enough to melt 5e18 kg of rock, which is 100 times as much mass as the asteroid itself. Figure a small fraction of that will vaporize and the whole mess goes suborbital.

For the next hour you have thousands of trillions of tons of glowing molten lava raining down on everything. Everything that can burn (6e14 kg of carbon in the world's biomass) does so, promptly.

And this asteroid impact thing has actually happened, many times. As Ed says, it's like pushing Ctrl-Alt-Del on the whole world.

Side notes: There is 1e18 kg of oxygen in the atmosphere, far more than necessary to burn every scrap of biomass on earth. The story I read was that the oxygen in the atmosphere came from plants. If so, there must be a lot of carbon buried somewhere: 8.6e14 kg of known coal reserves are less than 1%.

Another interesting point, vis-a-vis ocean fertilization: there is about as much carbon in the atmosphere as in the world's biomass. We'd have to boost the productivity of 1/10 of the world's ocean by a factor of 8, from existing productivity (125 gC/m^2/year), to fix the CO2 problem in the atmosphere in 15 years. Ocean CO2 would take a century or more. That productivity boost is like converting that much ocean into a coral reef! This seems like a lot to me.