Thursday, 23 December 2010

Once in a Red Moon

It seems that the December 21 of 2010 was quite saturated with important events. A very total and spectacular lunar eclipse took place last Tuesday. A lunar eclipse as we all know occurs when the Earth comes directly between the Sun and the Moon. The Earth casts it's shadow on the moon and the full moon disappears from the night sky for a while. Well, not quite. This is what actually happens.







As you can see the moon is never completely in the Earth's shadow. Instead at the peak of a lunar eclipse, the moon appears blood red. All of you will have seen a sunset, at least in pictures. The sun appears red because it has to pass through much more of the atmosphere that when it is directly overhead. In this case the sun's light passes through a similar amount of atmosphere before it falls on the moon. Radiation of shorter wavelengths are scattered in the atmosphere leaving wavelengths we perceive as red to go through and fall on the lunar surface. This causes the moon to glow in a most enchanting red colour. Certainly one of the more beautiful celestial events.



9 comments:

Kian Seng said...

I saw that in the middle of the Pacific Ocean on the way to Isle of Pines, New Caledonia.

Blood red alright and cuz the skies above the sea is relatively clear and unpolluted, it looked even more glaring and awesome.

Ashwin Narayan said...

So now you know why it happens. You learnt something interesting today.

Kian Seng said...

LOL, I learnt that in primary school...lol

Ashwin Narayan said...

You too?

Evee said...

PLUS MY BIRTHDAY HAHA :D

Ashwin Narayan said...

Yes. I'm slightly envious of you Evelyn. Your birthday falls on such an important date!

The only event of any significance happening on my birthday is International Women's Day. Winter Solstice is a lot cooler.

PS: I mentioned your birthday in my previous post on the Winter Solstice. It's at the very end of a lengthy paragraph, you might have missed it.

Kian Seng said...

The International Womens Day is WAYYYY more important than Winter Solstice...pfft, who cares whether day is longer than night or vice versa when WOMEN form more than 50% of our world's population...

Ashwin Narayan said...

No it certainly is NOT! No offense to all the women out there but Winter Solstice was around ever since the formation of the Earth about 4.5 billion years ago.

By comparison humans have only been on Earth for about 200000 years. The entire human race has been around for only about 0.004% of the Earth's history.

It is nothing but arrogance to say that a celebration on a purely arbitrary date is of comparable importance to an event which happens at a very precise instant and is completely uninfluenced by our calendar. It happens on its own.

Ashwin Narayan said...

Winter solstice ha outlived humanity by several billion years.