by Nancy Kirkpatrick Wright
On Tuesday morning, June 8, 2004, the bright planet Venus will move in front of our sun–a transit of Venus–and millions will watch through strong filters as a small black dot moves across the lower part of the sun. Scientists and astronomers are excited since no one now alive has seen a transit of Venus. There were no transits of Venus in the 20th century–the last pair being 1874 and 1882.
In December 1874 Prescott was ten years old and the Weekly Arizona Miner published this one-liner: "Teheran, Asia, Dec. 9.–The observations of the Transit of Venus here were very successful." That’s all. Nobody took much note of it. Headlines that week reflected disagreements between cattlemen and farmers, "Fence or no Fence", the usual political blustering, "malicious liar, "unmitigated falsehood" and " connivance in the use of government property." In the Territorial legislature a bill had been introduced to build a penitentiary. Furthermore, two women were shot at the fandango Saturday night on Whiskey Row.
Eight years later, upon the transit of Venus’s twin occurrence, December 1882, the Miner failed to record it at all. Frederick Trittle had recently been appointed governor of the Territory and eighteen-year-old Prescott boasted about 5,000 residents, five churches, two schools, and eighteen saloons. Buckey O’Neill had joined the Arizona’ Miner’s staff that year. News revolved around stage robberies and of course, the usual fandangos on Whiskey Row.
By 1882 twelve-year-old Sharlot Hall and her family living in wagons and tents along the banks of Lynx Creek, were much too busy with the hardships of day-to-day existence to take note of distant astronomical events. Years later, though, Sharlot would write about taking a train down to the mining camp at Congress to observe an occultation of Venus. With sentimental, flowery adjectives and themes of death and resurrection, Sharlot described Venus–"a jeweled crown for an old man’s brow." Although not her best poem, it painted a vivid picture of the rare event and her feelings at the time. The moon moving in front of the planet Venus, an occultation, though rare, comes along about once every eight years, while transits come in pairs 122 years apart.
The great American "March King," John Philip Sousa, probably watched the 1882 transit for he soon wrote a musical march, "The Transit of Venus" and a novel of the same title. Sousa’s music was destroyed in a flood, but an old copy has been found in the Library of Congress and the march, described as "a little three-minute gem" was played by the Virginia Grand Military Band last November. Chances are you will hear this March played on NPR sometime between now and June 8.
So, just what is a transit of Venus? It occurs when the path of the planet Venus moves between the Earth and the sun. The planet moves slowly, taking about five hours to cross from one side of the sun to the other. It must be observed through strong filters because looking directly at the sun will cause blindness.
Before the invention of the telescope, a few astronomer thought they had seen a transit of Venus, but they were actually seeing very large sun spots, which can be seen with the unaided eye (using a solar filter, of course). As far as we know, only five transits have been witnessed by humans.: 1639, 1761, 1769, 1874, and 1882.
The most interesting of these historic observations was Captain Cook’s who followed Edmund Halley’s instructions. Halley (he of comet fame), like scientists for hundreds of years before him, was seeking a way to measure the distance from the earth to the sun. After watching a transit of Mercury–a smaller planet, as it moved across the face of the sun, Halley had the idea of using the occasion of a transit to determine the "astronomical unit," that is, the average distance between the earth and the sun. If the transit were observed from many widely separated stations, the tracks across the sun and the time they took, could be recorded and compared and the distance to the sun could be calculated.
You probably remember that although Halley had predicted the arrival of the comet named for him, he didn’t live to see it. ‘Same thing happened with the transit of Venus. Halley died years before the 1761 transit of Venus. Although the 1761 transit was watched at some seventy stations around the world, (the largest scientific attempt up to that time), the results were disappointing. Bad weather, navigational errors, and difficulty timing Venus’s image against the sun, all contributed to the failure. However, with the twin transit coming up in eight years, scientists planned carefully and managed to send out many observing parties, including the intrepid British seaman, James Cook. Captain Cook with Halley’s instructions, a couple of scientists, and a lusty crew, headed his good ship Endeavour to the South Pacific and managed to view the whole thing. Measurements gathered by Cook and others in 1769 were pretty rough but their calculations gave the best earth-sun distance at the time.
Today there are better ways to measure astronomical distances and we can entertain ourselves for hours looking up transits of Venus on the web. Scientific books are being published on the subject as well as novels, magazine stories, and newspaper articles. It’s scientific. It’s historic, It’s a rare event. Remember the date, June 8. Folks on the East Coast will be able to see part of it and people in Europe, North Africa, and parts of Asia may watch the entire transit.
If you miss this one, there will be a repeat performance on June 6 of 2012, visible over the Pacific Ocean, Siberia, Japan, and Australia. After that it will be 122 years before the next pair of transits: 2117 and 2125.
Sharlot Hall Museum Photograph Call Number: (la154.1pe ). Reuse only by permission.
Humankind has been gazing at the night sky since the beginning of time. This is a view of the full moon over Little Pond on the west bank of Willow Creek, c. 1905.