MAY 9 TRANSIT OF MERCURY - Rarest of the rare

P. Clay Sherrod

Take a vacation day or call in sick on MONDAY, May 9 for the duration of the all day celestial event of the rarest kind will take place starting at dawn and lasting until afternoon.
At 6:16 a.m. Central Daylight time, Mercury will slowly begin to crawl across the surface of the sun as we see it from Earth; in central parts of the USA, the sun will not yet be up;  however when it does rise, look for a tiny black round dot on the very eastern edge of the sun.  That will be Mercury; as the day progresses, the tiny planet will slowly move west-southwest across the sun, appearing midway across the huge bright disk about 9:57 a.m. CDT.  The transit will last until about 1:30 CDT....providing an all day event for daytime stargazers!

An interesting aspect of any transit is the relative sizes of these objects; Mercury is about 52 million miles away, while the sun in 93 million miles away; the sun is so huge that even at nearly twice the distance it still dwarfs the tiny innermost planet.

The event is so rare that only a maximum of 14 such transits of Mercury take place every century, surpassed only in rarity by a transit of VENUS which can happen only twice per century!
Don't miss it!

Mercury transit disk plot 3
This graphic shows the progression of Mercury during the May 9 day-long transit; NOTE
that times on this graphic, courtesy Sky and Telescope, are in EASTERN time!
NEVER look at the sun without a properly filtered telescope or solar filter.  For suggestions toward safe viewing, please see:

sun eclipse viewing 120509b 02

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