Transit of Mercury

Astronomy is exciting when things pass in front of other things.  It can teach us a lot, like when galaxies pass in front of other things in deep space, which can cause a phenomenon called gravitational lensing.  Or, it can just look really swell and give us a window into how everything is moving around out there, as in eclipses.

Today, witness a fairly rare event: a transit of Mercury across the face of the sun.  You can get more information and witness a broadcast online at the Exploratorium.  The transit begins about 2:15pm Eastern Time.  Hopefully the webcast will be worthwhile: it's a reduced size image suitable for internet broadcast, of something already small and sort of fuzzy if you're not looking closely.

This is similar to a solar eclipse in that we'll see one object passing between us and the sun, manifesting in a shadow of that object.  The difference is that while the angular size of the moon is just about that of the sun from Earth perspective, resulting in occasional total eclipses, Mercury appears much, much smaller.  Like, this small (image from Exploratorium site):



I was fortunate to see the 1999 transit live through a solar telescope.  But that time, Mercury just clipped the edge of the solar face.  This time it will catch more of the disk from where I'm at, and will take around five hours.  On the east coast, the sun will set before the transit is finished.

Posted at 10:34AM Nov 08, 2006 by WILSON, JOSHUA in Bits of news  |