On the 20th Sept. 331 B.C., before the Battle Of Gaugamela between Alexander III of Macedon (Alexander The Great) and Emperor Darius III of Persia, an eclipse of the moon was observed.
Despite Alexander's army being considerably outnumbered, to astrologers of the time, the eclipse foretold Darius's defeat. As night fell on the battlefield, the eclipsed moon glowed a deep blood red, signaling blood would be spilled on that night, but not in Alexander's army.
As history shows, Alexander won the battle and it is thought the favorable forecast from astrologers gave his army the lift they needed (also, astrologers on the Persian side are rumored to have been bribed to foretell doom among Darius's men, impacting morale).
Throughout history there are countless examples of when eclipses have foretold doom. Significant events are chronicled to have taken place, shaping our past based on documented lunar eclipses. Nowadays, we know that these events simply coincided with the alignment of three celestial bodies, resulting in a stunning astronomical sight.
Lunar eclipses occur when the sun, Earth and moon sit in alignment and the Earth blocks sunlight from reaching the moon. Usually, of course, we can only see the moon because it reflects sunlight. But during an eclipse, the source of light is blocked and the moon's disk goes unusually dark.
However, the moon doesn't completely disappear since the gasses in our atmosphere act to bend some of the blocked sunlight, directing the red part of the solar spectrum back to the moon. Sometimes this has the effect of turning the moon a deep red, often blood red. The mechanism behind this phenomenon is called " Rayleigh scattering."
Sometimes the moon doesn’t completely fall into the shadow of the Earth, however. When this happens we see a partial lunar eclipse where only some of the moon goes dark -- only when it sinks completely into our shadow we see a total lunar eclipse.
An event like this occurs on Wednesday June 15 starting at 17:23 UT (6:23 p.m. GMT) and finishes at 23:02 UT (12:02 a.m. GMT, June 16). Note: The eclipse will not be visible from the USA, as it will be daytime when the eclipse occurs.
During this period, the shadow of the Earth will slowly drift across the moon. The moment when the moon begins to be completely shadowed by the Earth will be at 19:22 UT (8:22 p.m. GMT) -- this is known as the start of totality. It will end at 21:02 UT (10:02 p.m. GMT) when the shadow will once again be seen to slip slowly across the surface of the moon.
Just how red it will appear during totality will depend on the conditions in our atmosphere. If there is a lot of dust from a volcanic eruption, for example, the lunar surface may turn a dark brown, but if the atmosphere is clear, it may turn a striking blood red. It's never easy to predict quite how it will look, so keep your eyes peeled.
Unlike solar eclipses where the moon blocks the sun from our view in only a few locations on the planet, for lunar eclipses, as long as you can see the moon then you will see the eclipse.
For your location, check the time of moon rise and if it happens before or during the eclipse then hopefully you should see something quite spectacular.
For more details of its visibility, browse this helpful NASA link.
© 2012 Discovery Channel