The most notable of the early European explorers was Captain James Cook, the famous British explorer and navigator, who in three epic voyages was responsible for mapping much of the Pacific including New Zealand. It is hard to fathom the skill, courage and leadership of this early voyager sailing thousands of miles across largely uncharted areas of the globe. Captain Cook was the original Captain Kirk boldly going where no one had gone before.
I want to go as far as I think it possible for a man to go.
-Cook in his journal
Cook’s early history is remarkable in that he was a farmer’s son, not an aristocrat from birth like most British Naval Officers at that time. Instead Cook rose up through the ranks in the merchant navy. Then in his twenties, he decided to join the Royal Navy where he had to start at the bottom again as a lowly seaman. His knowledge particularly his navigation and cartography skills were soon recognized and he rose up through the ranks becoming a Lieutenant.
There was much in-fighting in England for who would lead what would become Cook’s first voyage across the Pacific one of the aims of which was to make astronomical observations from the island of Tahiti of the transit of Venus across the sun. Finally Cook was given the position; a 4-year old squatty converted coal ship (106 feet long and 29 feet wide) was chosen for his craft and was renamed ‘Endeavor’. You might take the time to measure for yourself the size of this vessel just to appreciate how small it was, and on this Cook and his crew would go on a voyage of several years (1768-1771) duration.
Replica of Endeavor
Joseph Banks, who was also to achieve fame from this voyage, was a playboy turned botanist. Having inherited wealth at a young age, he was well educated but could not find any particular course of study to his liking until he developed an obsession with botany. Banks wanted to go on this voyage at any cost hoping to jostle for de facto control of the Endeavor even though Cook was to be captain. To secure a spot on the voyage Banks paid 10,000 pounds (several million in today’s money), which was almost three times the amount of King George III’s patronage for the voyage. By comparison Cook received a salary of 105 pounds/year. Along with the 2 artists and 4 servants that made up Bank’s personal entourage were 2 greyhounds that Banks claimed he would use for hunting in Antarctica! Banks however was a brilliant botanist, and along with one of the other naturalists on-board, Daniel Solander, would make lasting contributions in chronicling the natural history of the Pacific.
The crew however signed up to go on this voyage for primarily one reason—sex in Tahiti. Another ship had come back to England reporting that not only would the Tahitian women have sex but they will swim and paddle out to the ship! And the previous crew reported that to buy sex it had only cost a single nail. Apparently by the end of their Tahitian stay, many nails were missing from the planks of that specific ship. You have to remember, the Tahitians did not have metal and nails could be melted and formed into various ornaments and more particularly tools which lasted farther longer than the predominantly wooden tools that they had. So regardless of any one’s particular morals, it wasn’t a terrible deal for the Tahitians either. Later while in Tahiti, not so much to preserve any moral integrity amongst the crew but literally to preserve the actual physical integrity of his ship, Cook forbade the exchange or trade of any metal items.
The Endeavor departed England on August 26, 1768 with a crew of 94 men and arrived in Tahiti around eight months later. After Cook had recorded the transit of Venus across the sun in Tahiti, he was to open secret orders from the Admiralty that were to remain sealed until that time.
But first, why did Lieutenant Cook (he wasn’t a captain yet) travel truly half way around the world to watch the planet Venus pass across the face of the sun? And what does this have to do with a travel blog about New Zealand? Well, to answer the second question first—absolutely nothing.
Transits of Venus are similar to solar eclipses in which the moon passes across the face of the sun, except in this case, Venus passes across the face of the sun. However transits of Venus are rare events. They occur in pairs eight years apart approximately every 120 years. The last two were in 2004 and 2012. The transit itself as viewed from earth lasts several hours.
In Cook’s day, astronomers knew of six planets and knew their relative spacing from the Sun due to Kepler’s laws. For example, they knew that Jupiter was five times farther from the Sun than the Earth, but they did not know any of the actual distances. Edmund Halley, of Halley’s comet fame, postulated in 1716 that if the start and stop times of a Venus transit could be recorded from several different locations on the earth, then using the principle of parallax the distance to the Sun could be calculated.
Here’s basically how it worked. For observers at widely different locations on the Earth, Venus will not enter the Sun’s disc simultaneously, nor leave it. If all parties have identically accurate clocks on Greenwich Mean Time, then the exact time that Venus first completely enters the Sun’s disc, will reflect a slightly different angle from earth to Venus from one location to another. Since the difference between the locations on Earth are known, then after making a few adjustments for longitude and latitude, and the movement of the earth itself, simple trigonometry can be used to calculate the distance to Venus. Then since the proportional distance of the planets to the sun were known, once the distance to Venus was known, then the distance to the Sun could be calculated. Make sense?
In 1761 an international scientific team had tried to record data on the Venus transit from different locations but weather and other factors had made their measurements unreliable. Therefore, the attempt in 1769 was crucial. It didn’t need to be said, that if botched, every astronomer alive at the time would be dead by the time the next transit rolled around in 1874.
Cook arrived in Tahiti two months before the transit. Setting up his makeshift observatory at a point he aptly named “Point Venus”, observations were made on the appointed day. But unfortunately, despite data from 76 locations around the globe, the data was later found not precise enough to accurately determine the true scale of the solar system.
Once Cook’s observations were completed, he opened the secret orders from the Admiralty that had remained sealed up until that time. The orders directed him to sail the south Pacific in search of what was then termed the continent of Terra Australis. ‘Directly to the Southward in search of the Continent’ the orders commanded.
As early as 140 AD Ptolemy, the Greek geographer, had postulated a landmass contiguous with Africa and South America stretching across the Southern Hemisphere. His name for it was Terra Incognito or “unknown land” and its existence was deemed essential to counterbalance the landmasses in the Northern Hemisphere and to prevent the earth from wobbling off its axis and spinning off into space. For years explorers would roam the southern seas unsuccessfully searching for this counterweight continent. It’s gotta be down here somewhere!
(to be continued)