At 12:47 Eastern Time or 17:47* Z time, formerly Greenwich Mean Time, the earth reached its furthest tilt away from the sun, which rises only to the Tropic of Capricorn. As everyone knows, the earth’s axis of rotation is tilted away from the plane of its revolution around the sun by about 23.27 degrees. On the winter solstice, the that axis is pointed directly away from the sun. The north polar regions are in darkness and get very cold, spilling their cold air down over Canada, Scandinavia, and Russia. At the same time, the earth is relatively close to the sun, showing that spreading the sunlight over a large area has much more effect than a small change in distance. The southern polar regions get almost continuous daylight and the tropics have their summer, made even hotter by closeness to the sun.

In spring and fall, the sun shines towards the sides of the axis and sunlight falls evenly on north and south. In the summer, the earth’s axis tilts towards the sun. The North has its summer and long days, while the South has its winter and short days, made even cooler by distance from the sun.

In Northern Europe, the short, cold days and long, depressing nights, so soon after the late harvest and autumn slaughter of animals for winter food, made a cheering feast when the sun began to rise higher in the sky and the days began to lengthen. This festival has come down to us as Yule.

*Correction: 17:47, not 16:47. I can never get that “Spring forward, Fall back” rule reliably correct.

P.S. See “Keep Han in Hanukkah.”

Science artist Mark Whitton offers a unique snow scene on his greeting card.

Trouble in the Message Centre, originally uploaded by Mark Witton.

Hark, the herald pterodactyl sings,
“Peace to all on leath’ry wings.”

This is old news, but summarizes a study where participants ate a low-carbohydrate diet, and found it easy to lose weight. Without trying, they ate 1000 calories less per day. It seems to reflect the old wisdom that some foods “stick to your ribs” and avert hunger.

ScienceDaily (Apr. 7, 2005) — PHILADELPHIA (March 15, 2005) — A new three-week in-hospital study of 10 volunteers found that during the two-week period on a strictly controlled very-low carbohydrate diet, participants lost an average of 3.6 pounds, voluntarily reduced their calorie intake from 3,111 calories per day to 2,164 calories per day, and did not eat more of the readily available fat and protein to make up for the lost carbohydrate calories.

The study, “Effect of a Low-Carbohydrate Diet on Appetite, Blood Glucose Levels, and Insulin Resistance in Obese Patients with Type 2 Diabetes,” compared a very low-carbohydrate diet with a regular diet. It is published in the March 15, 2005, issue of Annals of Internal Medicine.

Who raised false alarms about vaccines and why?

Andrew Wakefield was made half a million pounds and stood to make millions more on a patent for a single measles vaccine.

The mercury scare confuses methyl mercury (poisonous) with ethyl mercury (non-toxic).

These people can kill you.

When you treat yourself with water, you neglect effective treatments.