January 14, 2005

Longer Days, But Here Comes the Sun

January 14th, Pongal. Makar Sankranti here in Bombay. Consider the length of the days since the winter solstice on December 22, the shortest day of the year. (Well, shortest here in the Northern Hemisphere).

On December 22 '04, the day (sunrise to sunset) lasted 10 hours and 59 minutes in Bombay. It lengthened to 11 hours the next day, and stayed there till December 30, when it stretched to 11 hours and 1 minute. On Jan 3 '05, it got to 11:02; then 11:03 on Jan 6, 11:04 on the 9th. Today, Jan 14, the day will last 11:06 hours.

Nothing odd there, the days are getting longer, is all. As they should.

But now consider sunrise since December 22. That day, the sun rose at 0708. 0709 on the 24th, 0712 by the 31st, 0713 on Jan 4th. Today, Jan 14, the sun rose at 0715, which is the latest it will rise for the year. In a few days, the sun will start rising earlier every day.

What's happening here? The days are getting longer, as they should. But the sun has risen steadily later since the winter solstice. (The days have got longer for the last three weeks because the sunset has got steadily, and correspondingly, later). Today, January 14, is when this trend of later sunrises finally turns around.

A small prize of my choosing to those who can adequately explain why this is happening. And tell me what, if anything, it has to do with January 14th and Pongal.

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