Tuesday, 21 December 2010

Winter Solstice

Today, 21 December 2010 is a day of great importance. Today is the day the Earth's axial tilt is at it's maximum of 23° 26' away from the sun. If measure the angle of elevation of the sun from the horizon at twelve noon today you will measure an angle of 69° 34'. It certainly brings back memories. If you were a reader of my blog exactly a year ago you might remember my creative technique of measuring the Earth's axial tilt. For those who weren't there, you should know that I managed to calculate the axial tilt of the Earth by measuring the angle of elevation of the sun on the day of the winter solstice. While this in itself is not very impressive, the method I used to calculate the angle of elevation of the sun is very interesting. I did not measure the angle directly. I used a more long winded but safer method of using shadows and similar triangles. If you are curious read this post: http://ashwinnarayan.blogspot.com/2009/12/tilt-of-earths-axis.html then this post http://ashwinnarayan.blogspot.com/2009/12/few-clarifications.htmlI say my method was safer because looking directly at the sun is never a good idea unless you are hell bent on inflicting permanent damage on your eyes. The most impressive thing is that my measurement was very accurate. My answer was very close to the original value.

Historically, the winter solstice is a very important date. There are several festivals celebrated by almost all of the ancient cultures of the world that depend on the winter solstice. A very famous example is the Jewish festival Hanukkah. There are several magical tales and legends associated with this date. It is apparent that humans felt that solstice was a very mystic event.

Recently the date December 21 has gained quite some fame after the sudden surge in the interest the public has shown towards Nostradamus's predictions. Apparently he said that the world as we know it would end on December 21, 2012 due to the Earth, the moon, the sun and the centre of the galaxy lining up. Some people also believe that a fictional Planet Nibiru will come zooming into the solar system and knock Earth off it's orbit.

As someone strongly believes that  good science must be promoted and bad science must be debunked,  let me make an announcement. The world WILL NOT end on December 21, 2012. Period. It is a fantastic work of fiction. If you check the star charts you  will see that this alignment of the Earth, Moon, Sun and the centre of the galaxy happens EVERY YEAR. I thank my favourite astrophysicist Dr. Neil deGrasse Tyson for making me aware of this and for showing a contagious enthusiasm in science that has made the world a better place. So for those who are waiting for the end just take a step back and think for yourself. Do not be misled by pseudoscience.

On a different note today is also the birthday of my good friend Evelyn Chua. I wish you a very Happy Birthday!


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