OUR MOON QUIETLY GROWS TO SUPERMOON SIZE
Tom Logsdon “Hi diddle diddle, The cat and the fiddle, The cow jumped over the moon. The little dog laughed, To see such fun, And the dish ran away with the spoon.” My mother taught me that playful English nursery rhyme when I was about nine years old.. Notice how the poet who wrote […]
Tom Logsdon “Hi diddle diddle, The cat and the fiddle, The cow jumped over the moon. The little dog laughed, To see such fun, And the dish ran away with the spoon.” My mother taught me that playful English nursery rhyme when I was about nine years old.. Notice how the poet who wrote it couldn’t think of anything more fanciful than having a living, breathing creature ending up in the vicinity of the moon! It took 300,000 of us a full decade of very hard work, but we did it! We sent two dozen astronauts on the adventure of a lifetime and we brought all of them back alive. In 1961 President John F. Kennedy, youthful and exuberant and brimming over with confidence, announced to the world that America’s scientists and engineers would—within a single decade —land a man on the moon and return him safely to the earth. No cows need apply. But potential human astronauts were bigly and hugely enthusiastic about their new opportunity to fly through space to a different world. By using the math and physics we had learned in school, we covered hundreds of pages with with cryptic mathematical symbols to work out the details down to a gnat’s eyebrow. We ended up hurling 24 American astronauts into the vicinity of the moon!. 12 of them “kangaroo hopped“ on its surface. Earlier this month, when the moon grew to its maximum apparent size, we were all reminded of the excitement we felt during Project Apollo. Of course, the size of the moon did not actually change, it merely moved up to its point of closest approach. Systematic perturbations on the moon’s orbit coupled with rhythmic variations in its distance from the Earth as it traveled around its elliptical orbit resulted in surprisingly large variations in its apparent size and its brightness as seen from the Earth. These distance variations, in turn, cause its observed diameter and its brightness to vary by as much as 15 and 30 percent, respectively. When the moon approaches its maximum apparent size and brightness, it is characterized as a supermoon. The biggest and brightest supermoons are spaced out several decades apart. My son, Chad, who participates in Special Olympics, used his cellphone camera to create the two photographs that accompany this blog. He took the first picture at the crack of dawn when the moon reached its maximum diameter at the edge of the parking lot at the Embassy Suites Hotel in Lexington, Kentucky (population 360,000). He made the second photograph 12 hours later in my hometown of Springfield, Kentucky, ((population 2900). That second picture was made on a small roadside hill beside the Bardstown Road above the IGA Supermarket within sight of the yellow blinker light at the edge of town. Author and short-course instructor, Tom Logsdon, who wrote this article, teaches the Launch and Orbital Mechanics short course for The Applied Technology Institute. Click here for more information on that course. He also teaches the GPS and Its International Competitors short course. Click here for more information.