Monday, April 24, 2006

Field notes

1. Vega rises in the northeast as the sky darkens, a teasing taste of summer. It is the second brightest star for northern hemisphere observers, after Sirius, mainly because it is relatively nearby, only 25 light-years from the Earth, a star in the prime of life, bigger and brighter than the Sun.

The 13 April issue of Nature has a new analysis of Vega's spectral characteristics that suggests the star is rapidly rotating -- nearly fast enough to tear itself apart. From Earth, we are looking at the star along its axis of rotation. It is a younger star than the Sun, about half-a-billion years old, surrounded -- like the bull's-eye of a target -- by a disk of dust and gas.

Three pages of data and graphs and mathematical analysis of a point of light in the night sky. I tuck it away. I file it in my brain in a folder marked "Vega: Summer Stars." And tonight (or the next night it's clear), when the star rises jewel-gorgeous in the northeast, winking at Jupiter in the south, I'll see it not only with the eye of vision, but also with the eye of the imagination -- a ballerina whirling out her skirts of protoplanetary dust.

2. No fifth egg this morning in the phoebe nest. Perhaps she's finished at four, although I'll check again on my walk home. Hard to believe that each of those tiny eggs -- no bigger than the tip of my little finger -- will become a chick.

The first-time phoebe mother mates, builds (or repairs) a nest, lays eggs and incubates them by instinct, presumably with no notion that baby birds are on the way. But when they hatch, she'll know what to do, again by instinct.

It is only through the cultural transmission of knowledge that a first-time human mother anticipates a child. Will the phoebe remember what's in store when she broods her second clutch of the season? Next year? Here's a subtitle from a story in the February 2 issue of Nature: "Despite its tiny size, the fruitfly brain is staggeringly intricate. So teasing apart how it remembers things -- even a simple line pattern -- is a daunting task."

Later, PM: Looks like I was the early bird. The phoebe did indeed produce a fifth egg, one a day, like cluckwork.