The Transit of Venus

The Transit of Venus has been all over the news recently, mainly because this is the last opportunity to see it for virtually everyone who is alive today. The next one will not occur until 2117.

But do you know its historical and scientific importance? That's right, this isn't just a pretty light show. Over the last four hundred years, this rare occurrence held the key to determine the size of our solar system, and as the following primer shows, the individual pieces required to put the whole together spanned the gamut of scientific and mathematical thinking, and involved some incredible minds:

But this general idea goes far beyond merely determining the size of an astronomical unit: it can be used to detect and measure planets in other solar systems too:

And here it is, in all its spectacular beauty, footage of the 2012 Transit of Venus: