As I write, a total eclipse of the Sun is speeding across the Indian Ocean. This magnificent natural spectacle has just crossed Africa in half an hour flat, and is heading for sunset on the southern coast of Australia. The path of the eclipse is no more than 55 miles wide, and the eclipse only just lasts for two minutes at its maximum extent, except you'd have to be in a boat off Madagascar to see that.
A total eclipse of the Sun is as rare as it is spectacular. On average, a total solar eclipse only happens about twice in three years, and you actually have to be in the right place at the right time in order to see it. For a given spot on the Earth a total solar eclipse is only visible about every 360 years on the average, although they're distributed so randomly that a given spot might not see a total eclipse for centuries, or might see two within a few years. There's a point on the west coast of Angola that's just been eclipsed this morning and was also in the path of the last total eclipse 18 months ago. However, the USA isn't due to see another total eclipse until 21 August 2017, and mainland Europe has 24 years to wait, and even then only across a bit of Spain. As for the next total eclipse visble from mainland Britain, alas that isn't due until 23 September 2090, which means that most of us alive today will have been eclipsed before the Sun is.
I went to Cornwall to visit Britain's last total solar eclipse on 11 August 1999. I'd been looking forward to it for years and I was really glad to have the opportunity to be there, in the path of the solar shadow. Every morning of eclipse week the sun peeked through the clouds at ten past eleven, except on the one day when it really mattered. At the appointed time on Wednesday the clouds suddenly got very dark, and then two minutes later they suddenly got very grey again. It wasn't quite what any of us there had hoped for. In fact it was rather like having to wait twenty years to visit a sweet shop, only to get there and find it closed. It was an eye-opening experience alright, but the whole trip was somewhat of a disappointment. Ah well, one day I plan to be in the right place at the right time.
