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Transit of Venus

Posted Jun 05 2012 10:52pm

We went to one of our local universities this evening to watch the Transit of Venus under the tutelage of people associated with the Department of Physics and Astronomy in the Faculty of Science. The shadow of Venus traversed the sun many times before people noticed the tiny dot on the blindingly bright sun surface. If everyone was like me, no one would have discovered it yet. The dot is very, very tiny indeed.

You cannot see anything but the sun through these glasses
We lined up and got our protective eyewear. Some people came prepared with large shadow boxes, modified binoculars, special cameras and telescopes.

The sky was overcast all afternoon but started to clear as the transit began. The sun hid frequently behind big dark clouds and people waited patiently for it to reappear.

When the sun reappeared, the protective lenses went on and we could see the dot had progressed a few degrees from its one o'clock position toward the centre of the sun.

There were a lot of children present for this rare event. Transits come in pairs that are eight years apart, followed alternately by spans of 121 ½ years and 105 ½ years. In the 21st century, the transit pair occurred June 8, 2004, and today, June 5th or 6th depending on your time zone. The next transit is December 2117 and even the youngest baby today is unlikely to see it.

I can see the little dot at 1 o'clock in this picture taken through the protective lens.
The last set of transits were in 1874 and 1882. In 1882 William Harkness, Director of the U.S. Naval Observatory wrote,

"We are now on the eve of the second transit of a pair, after which there will be no other till the twenty-first century of our era has dawned upon the earth, and the June flowers are blooming in 2004. When the last transit season occurred the intellectual world was awakening from the slumber of ages, and that wondrous scientific activity which has led to our present advanced knowledge was just beginning. What will be the state of science when the next transit season arrives God only knows. Not even our children's children will live to take part in the astronomy of that day. As for ourselves, we have to do with the present ..."

No one could have imagined the changes in science and the world between the last transit and the 21st century. And no one can imagine what the next 105-1/2 years may bring.
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