Category: Space & Science

Today is Don Knuth‘s 70th birthday. He is a giant in the field of computing science, and wrote TeX, the mathematical typesetting system that is used in the vast majority of scientific writing today.

A great many people are writing birthday tributes today (you can start here).

I do not usually have the mental energy to delve into his monumental (and still-incomplete) The Art of Computer Programming, but whenever I do, it’s always rewarding.

And his volume of commentaries on all the verses numbered 3:16 of the Bible, illustrated by the world’s greatest calligraphers and typographers, is delightful.

Freeman Dyson, one of pre-eminent scientists of the past century, has an essay at Edge magazine on a controversial topic:

My first heresy says that all the fuss about global warming is grossly exaggerated. Here I am opposing the holy brotherhood of climate model experts and the crowd of deluded citizens who believe the numbers predicted by the computer models. Of course, they say, I have no degree in meteorology and I am therefore not qualified to speak. But I have studied the climate models and I know what they can do. The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests. They do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand. It is much easier for a scientist to sit in an air-conditioned building and run computer models, than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing their own models.

The scientific world is all abuzz today about the annoucement of the first discovery of an extra-solar terrestrial planet within the “habitable zone” of its star. The planet has been inferred to orbit its sun — the star Gliese 581 — at a distance that allows for liquid water to be present on its surface. It masses about 5 times as much as Earth, and is about 50% larger. If the 50% refers to radius, then the gravity on the star’s surface would be around 20 meters per second squared, which is just over 2 times that on the Earth’s surface.