Transit of Mercury

Nov 7, 2006 3:56pm

The rest of the universe will be utterly indifferent to how Americans vote.  Wednesday will bring one of those appealing cosmic accidents that show us how small we are. It’s a Transit of Mercury.  For about five hours, beginning at 2:12PM EST tomorrow, the planet Mercury will pass directly between the Earth and the Sun.  If Mercury loomed in the sky the way the Moon does, the result would be a total eclipse.  Instead, Mercury is about 1/179th as large as the Sun appears to us, so there will be a tiny dot moving slowly across the Sun’s face. Such transits are something that happen only about 13 times per century, even though Mercury whips around the Sun in only 88 Earth-days.  The planets circle the Sun in roughly the same plane, but since Mercury’s is a few degrees off of ours, it usually appears to pass a little to the north or south of the sun’s disk. At NASA’s Goddard Space Flight Center, the resident expert on such matters is Fred Espenak, who’s posted a lot of useful information HERE.  This, obviously, is not something to try to see yourself–this is where I’m obliged to insert the standard warning about the dangers of looking into the Sun–but the University of Hawaii is one of several groups offering WEBCASTS.  NASA has one HERE. On Wednesday afternoon, if you have a moment, you may want to take a look.  Perhaps you’ll give it a passing glance; maybe you’ll be mesmerized.  (Diagram of Mercury’s path across sun from Fred Espenak/NASA) ======= Orion Nebula Oh–one other thing.  NASA has combined images from the Hubble Telescope (which shoots mostly, but hardly exclusively, in visible light) and the Spitzer Space Telescope (which shoots X rays), to produce this very pretty picture. If you like, you can read more HERE.  But to be honest, I’m just posting the picture because it’s fun for the eyes.

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