Sunday, 27 September 2015

Lunar Eclipse

It’s Full Moon tonight, and the Moon happens at the moment to be closer to the Earth than usual, so it will look bigger. Furthermore, there will be a total lunar eclipse. What happens here is that the Earth is passing directly between the Sun and the Moon, so that no direct sunlight can reach the Moon. But the Moon doesn’t disappear altogether: Sunlight is refracted and diffused by the Earth’s atmosphere, so enough light ‘gets round’, as it were, to give the Moon a spectacular red colour. I’m not sure if a total eclipse will be visible from everywhere.
If you’ve not seen a total lunar eclipse before — or even if you have — it’s worth staying up to watch. Totality should occur, if my limited knowledge of astronomy is correct, at ‘real’ (what is known as ‘sidereal’) midnight, i.e. half-way between sunset and sunrise; clock time varying according to which time zone you happen to be in.

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