Tuesday, May 15, 2012

Zero Shadow Day

Two days back some of my friends put some photos and comments about "Zero Shadow day" on Facebook.
It was interesting to know about it.
Zero shadow means the moment when the Sun is exactly overhead. The shadow falls directly under you and there is not even slightest of angle to the shadow.
In pune this happened two days back on May 13. Depending on your cities latitude and longitude positions it occurs in different cities on different days.
Moreover this event is not rare, but actually take place twice in a year.
Once between December to June and the other one in the later part of the year.
First occurance is normally visible to most of the Indians but second occurance normally go unnoticed since its mostly rainy season during the time of this occurance.
A little attempt to know more about it put me to different query.
I started wondering if it happens only in India.
If you try to google "Zero Shadow Day" or "No shadow day" on google, all the links that would appear in the list comes from India only.I have been through 4-5 pages of google links and absolutely each one of these links are connected to India.
So, many questions come up.
1. Is my search biased?I understand that google produces results based on our previous search criteria keeping in its memory what kind of things we like to appear as the top most search. So, unknowingly if my Google search is biased then may be someone else need to crosscheck. But it is highly improbable. Even not a single hit for any other country based link is difficult to understand.
2. Is "Zero Shadow Day" not the real scieitific name for this event. Is it called by some other name? This needs to be verified. But if that would have been the case, some mention of the real scientific name would surely have appeared.
3. Does this happen only in India? I guess not. It can not be a regional phenomena.
4. Is it not an interesting event for the world that nobody cares to pen down some information about it accessible to everyone or Are only Indian too much enthusiastic about such planetary events.
5. Even Wikipedia has not page dedicated to "Zero Shadow Day" or "No Shadow Day".

For those who want to know more about "Zero Shadow day", I would like to direct you to this link:

http://skytonight.wordpress.com/2012/04/14/zero-shadow-day/

which very nicely present information related to ZSD with photographs and a video or shadow vanishing.

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