Astronomy Break

Usually there is not much reason to take a break in the middle of the workday for an astronomical observation. It is, after all, daytime. This past Wednesday was different because in the afternoon there was a transit of Mercury, which is when the innermost planet crosses the disk of the sun. This is a fairly rare event, only occurring 13 or 14 times a century. The next one is on 9 May 2016.

The weather cooperated for us in Davis, and despite the unsettled conditions this week, it was sunny throughout the event. Elsewhere in North America, observers weren’t so fortunate. After lunch, I went to the roof of the physics building where the UC Davis Astronomy Club had set up a telescope with a solar filter. Thanks to them, I saw the speck of a planet, sunspot-sized but perfectly round, against the face of the sun.

In 6 more years (5 June 2012) is a transit of Venus. This is a much rarer event, not to be missed — the next one occurs in 2117.