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A blood moon

The first of four lunar eclipses is seen in the night sky.

Last updated: 15 Apr 2014 20:18
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The moon has turned blood red in some parts of the world.

People in North and South America have been treated to the night-time spectacle, with those in northeastern Asia and Australasia having to wait for darkness to fall, before they could enjoy the later stages.

This is the first total lunar eclipse since December 2011, but there will be plenty more over the next two years.

The eclipse is the first of a lunar tetrad – a series of four total lunar eclipses, with no particle eclipses in between. The other eclipses in the series will occur in six-month intervals:

2014:
Total lunar eclipse: April 14-15
Total lunar eclipse: October 8

2015:
Total lunar eclipse: April 4
Total lunar eclipse: September 28

A lunar eclipse happens when the earth lies in between the sun and the moon. This means the sun’s light is blocked by the earth, and the moon passes into its shadow.

During the eclipse, the moon took on a dramatic blood red appearance. In ancient times this was thought to be a bad omen, but now it is understood that it is simply due to the scattering of light by the air in our atmosphere.

The scattering of light is something that happens every day. Blue light is scattered most effectively, and this explains why the sky is blue. Red light, on the other hand, is scattered least, which is why the setting sun is red.

When the sun, earth and moon are all lined up, the sun’s rays shine on the edges of the earth, and through our atmosphere. As they pass through the air, the atmosphere bends (refracts) them, and focuses them on the moon.

As well as being bent, the light has also been scattered. The blues and greens have been scattered, leaving only the red and orange tones. This gives the moon a strange red glow as it disappears into the earth’s shadow.

Unlike a solar eclipse, no special filters are required to protect your eyes. This means that this spectacle is completely safe to view with the naked eye, and for those who missed it, there is only a six-month wait until the next one.

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Source:
Al Jazeera
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