Science: Solar Eclipse 科学：日全食

Across Asia many people have just witnessed the natural wonder that is a total solar eclipse.

A total solar eclipse occurs when the Sun, Moon and Earth align in such a way that our view of the Sun is totally obscured by the Moon.

This week's total eclipse could be seen in eastern India before slowly moving across Burma, Bangladesh, Bhutan, China, Japan, and the Pacific Ocean.

Yesterday, when it reached eastern China, people flocked into the streets to witness the astronomical wonder.

As daylight disappeared and the sky quickly darkened, those watching were left far from disappointed. Cities such as Shanghai were plunged into darkness during what is thought be the longest total eclipse of the 21st century. It lasted 6 minutes and 39 seconds.

Total solar eclipses of such a long duration are very rare events, they happen but once in a lifetime. Shao Zhenyi, an astronomer at the Shanghai Astronomical Observatory in China explained:

"We'll have to wait a few hundred years for another opportunity to observe a solar eclipse that lasts this long, so it's a very special opportunity."

But while millions celebrate this phenomenon, it should be remembered that total eclipses have not always been such treasured events.

Many cultures traditionally believed that a total eclipse was a bad omen or a supernatural event. Some believed that evil gods were eating the Sun. Others believed that the eclipse signified oncoming disasters.

Nowadays it appears that these fears and superstitions are long forgotten. As daylight once again flooded Asian cities such as Shanghai, whoops and cheers could be heard among the gathered crowds.

Reflecting on what had just happened, one Shanghai resident described the eclipse as "eerie", whilst another said "It's like magic, the day turns into night in such a short period of time. I have no idea where I am right now. It feels like a different world."