Rarer than a blue moon

I just saw Venus transiting across the face of the sun. It's happening right now in western North America and will go on until sunset on the West Coast.

Tom was the one who set us up to see it. He focused the image of the sun through a pair of binoculars onto a piece of cardboard. We could see a sharp image of the sun's surface about an inch wide, with a pinhead dot at the lower right that was Venus.

[If you try this at home, don't look through the binoculars at the sun yourself; it's the last thing you'll ever see. ]

I will be long dead—and so will my kids—before this happens again, so a few minutes of watching an image on cardboard was more of a big deal than it seems. And it was surprising that the heavy clouds parted just long enough for us to see it. Living in Oregon, we're more used to missing cosmic phenomena.

I always get a geeky rush from seeing things with my own eyes. Probably the pinnacle until now was seeing Mars at its closest approach to Earth and being able to make out the ice caps at the top and bottom. This mans that photons traveled from the sun to Mars, bounced off the ice caps, zoomed back into our telescope and hit my retinas.

Total photon roundtrip time: 14 minutes 22 seconds. And why did I calculate that? Because I'm a total, utter, complete geek. I have no shame.

The next transit of Venus across the sun will be on December 11, 2117.