June 5, 2012

The Transit of Venus, Cook and Us


In 1769 Lieutenant James Cook traveled to Tahiti to observe the transit of Venus which occurred on Saturday June 3 rd:

This day prov'd as favourable to our purpose as we could wish, not a Clowd was to be seen the Whole day and the Air was perfectly clear, so that we had every advantage we could desire in Observing the whole of the passage of the Planet Venus over the Suns disk: we very distinctly saw an Atmosphere or dusky shade round the body of the Planet which very much disturbed the times of the contacts particularly the two internal ones. D r Solander observed as well as M r Green and my self, and we differ'd from one another in observeing the times of the Contacts much more than could be expected.”

The goal was to take measurements that would be used to calculate the distance of Venus from the Sun--which would then lead to knowing the distances of the other planets from each other. Unfortunately the instruments of the time were not fine enough for the effort and the measurements were too rough to be useful. But Cook’s voyage of discovery continued and he continued on in search of the “Terra Australis Incognita” in the South Pacific Ocean and discovered and charted the east coast of Australia.

 We learned this (and much, much more) after making landfall at Point Venus in Tahiti, anchoring where Cook did. It was part of what Maia called, “Sleeping where Cook slept. Can we stop now? Cook is getting on my nerves… I’m ready for a new topic.”

Point Venus though intrigued her. The low, sandy peninsula covered with ironwood is where Captains Wallis, Cook, Bligh (and us!!) landed after anchoring their (our!) ships behind the reef. Cook built a platform on the black sand beach near where a creek cuts the peninsula in two. It was here that he waited for an inky spot to glide across the sun. Small, dark, almost perfectly round, it was no ordinary sunspot—it was the key to measuring the size of the solar system. Or so hoped the Royal Academy, which sponsored Cook’s Voyage.

These days Point Venus is a park. And its highlights also include Tomb of King Pomare V and the phare (lighthouse) that was built by Thomas Stevenson, one of Scotland's famous lighthouse engineers and father of the author Robert Louis Stevenson. The park is steeped in the kind of history that’s impossible not to feel and not easy to shake off.

Point Venus
 And it came seeping back when we learned that Venus is transiting the sun, tomorrow. Not as dramatic as an eclipse—but much more rare, perhaps the best reason to watch the transit is a historical one. Already I can recall the heavy scent of tiare flowers, the weight of warm humidity, the feeling of black sand between my toes and that mysterious feeling of being linked to a memory I can’t quite recall.

Tomorrow is the transit of Venus. Check it out--just likeCook did 242 years ago. If you miss it the next one won’t happen until 2117.

2 comments:

Victoria said...

Thank you for your post! Because of it we made it to Point Venus for the occasion. There was a great camera obscura, some reenactments, and lots of presentations (science/history fair) by kids from all over Tahiti. We saw the transit!

Diane, Evan and Maia said...

Victoria that is SO cool. I'm so glad you got to do that. A bit jealous but really happy for you. Gorgous spot isn't it?