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Monday, May 14, 2012

Save the date: June 5 for Venus's trip across the Sun

Venus, named after the Roman goddess of love and beauty/Wikipedia

Sounds like the name of a song, doesn't it? Venus trips across the Sun?  John Philip Sousa has already written it.

A transit of Venus occurs when the planet passes directly between the Sun and the Earth, and it is a rarity, having occurred either six or seven times since the invention of the telescope.

Beginning at 6:03 p.m. on June 5 Venus will start its path across the Sun and will be visible to the U.S. until 8:26 p.m. when it gets too dark to see.  (How can scientists be so precise?)  The show will actually last past midnight, and on June 6, will be visible from much of Africa, the Middle East, Asia, and Europe.

Venus's route will run from west to east or from about the 11 o’clock to the 2 o’clock positions.  Unless you live until December 11, 2117, you'll never see it again.  (Special glasses recommended. It is inadvisable to stare directly at the Sun.)

In a talk last week at the Library of Congress about Venus's trip, NASA's Sten Odenwald revealed all kinds of interesting facts to approximately 75 middle-aged and above academicians (based upon appearances) who crammed the Mary Pickford Theatre.

NASA's Sten Otenwald/Astronomy Cafe

Evidence suggests that in 1520 Montezuma may have been able to see Venus trip the lights fantastic while Montezuma was studying the Sun for "portends." (?)  It wasn’t until 1639, however, that the first recorded sighting of the transit was made, and that was by William Crabtree and British cleric Jeremiah Horrocks.   

Printed literature at the lecture said that only six times since the invention of the telescope in 1609 or 1610 has Venus crossed between the Sun and the Earth, (news to Earthlings: The telescope inventor seems to be up in the air and may not have been the long-thought Galileo, who by the way suspected the love planet was more than just a bright light in the sky), however, NASA says that, excluding next month's transit, there have been seven Venus transits. (You know how persnickety academicians can be when it comes to dates, don't you? Someone may have excluded the transit in 1631 when no one recorded it, and anyway, who's counting? See chronology below.)

Venus's transit on Dec. 6, 1882, taken by students at Vassar College/Sky and Telescope, February, 1961

What’s weird is that Venus's trek across the Sun comes in pairs (of course! The love planet) that are eight years apart but separated by over a century (?).  This is so confusing I must quote from an original source before I screw it up:

Transits of Venus have a strange pattern of frequency. A transit will not have happened for about 121 ½ years (prior to 2004, the last one was 1882). Then there will be one transit (such as the one in 2004) followed by another transit of Venus eight years later (in the year 2012). Then there will be a span of about 105 ½ years before the next pair of transits occurs, again separated by eight years. Then the pattern repeats (121 ½, 8, 105 ½, 8). 

You got all that?  Good.

Venus's special one-way trip across the Sun led to the discovery of the solar system's size and the distance from the Earth to the Sun.  What?  (Do you remember what it is?  Answer at bottom.)

Now how in the world would Venus crossing the Sun provide knowledge about the Earth’s distance from the Sun? You must not remember your physics. Or your geometry, your chemistry, astronomy, and math.  Go back to school.

Venus's last Sun trip was on June 8, 2004 when sun storms were quieting, said Dr. Odenwald, but this time, sun storms will be more heated. 

Around the world hundreds of observation points are ready to take aim and record, and the entire transit will be broadcast from Hilo Station in Hawaii, from near the summit of Mauna Kea.

Kudos to Dr. Odenwald who was everything a listener would want a lecturer to be:   enthusiastic, animated, energetic, knowledgeable, humorous with lots of great illustrations to share, and seemingly happy to be presenting at the Library of Congress. He even had some music for his traveling show:   He played a few notes from a recording of Sousa’s “The Transit of Venus March.”   

Where will Dr. Odenwald be on June 5? Probably in Washington, D.C., he said, and maybe on top of the Library of Congress building which reminds me:

Attention Library of Congress:  The fire marshal would have had blown a fire ball had he or she seen people sitting on the steps and blocking egress in the Mary Pickford Theatre like they were for Dr. Odenwald's talk. It is obvious librarians are not safety experts, but really, the Library doesn't have a larger venue for popular talks?

    Transits of Venus:  1601-2200

1631 Dec 07                 

                        1639 Dec 04                

                        1761 Jun 06                

                        1769 Jun 03             

                        1874 Dec 09             

                        1882 Dec 06               

                        2004 Jun 08                

                        2012 Jun 06                

                        2117 Dec 11               

                        2125 Dec 8

Answer: 93,000,000 miles 

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