Shipwrecks & Transits

For those of you who don’t believe that anything interesting happens in Rhode Island, there was an occurrence that brought international attention to our fair state.  At a recent press conference, Dr. DK Abbass announced that there is now an 80% chance that Captain James Cook’s ship the Endeavour has been located in Newport harbor.  Present at the conference were so many members of Australia’s and New Zealand’s broadcasters that we in the hall couldn’t observe the PowerPoint presentation; to the persons Down Under, the Endeavour is equivalent to our Mayflower, and they hold Captain Cook in very high regard.

But, why should we care, despite the fact that a very historic vessel was deliberately sunk in our waters during the Revolution.  This ship, which did, in fact, introduce the southern lands to the British Empire, was the one that stopped at Tahiti in 1769, where Cook and his team set up an observatory in order to observe the transit of Venus. 

Hopefully, many of you were able to see at least a part of the recent transit of Mercury.  Although the day began fairly cloudy, the sky cleared early for us to enjoy close to seven hours of our tiniest planet appear to cross the surface of our Sun.  With solar filters, H-alpha telescopes, and even a Sunspotter, Brown’s Ladd Observatory had a steady stream of visitors able to view this phenomenon throughout the day.  And, everyone was amazed that the ball of the planet could be seen as easily as it was, as Mercury is just 1½ the diameter of our Moon, and close to 60 million miles away. 

A transit of Mercury, although fairly common, occurring about a dozen times each century, was first realized as an important, but really too small, way to aid in making sense of the size of our solar system.  Edmund Halley, observing this while on the island of St. Helena, saw the geometric potential for using a planetary transit to determine the yardstick for our neighborhood, the astronomical unit, the average distance between the Earth and the Sun.  Mercury was too small, in his opinion, to capture very good observations, but, Venus, over twice as large, and twice as close, would be an ideal planet to do so.  The transit of Venus in 1769 had astronomers travel all over the world, and Captain Cook and his crew, on Tahiti, was responsible for some of the better results.

Notice, unfortunately, the surety is not 100%.  Five British ships were sunk at approximately the same location, and four have been recognized as such; there is still one more ship waiting to be identified.  But, we know the Endeavour is there, and even if it is the still elusive bark below our waters, we can be proud that such an important, historic ship is now here.