Monday, 28 April 2014
Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997), also known as Gene Shoemaker, was an American geologist and one of the founders of the field of planetary science. He is best known for co-discovering the Comet Shoemaker–Levy 9 with his wife Carolyn Shoemaker and David Levy. Gene Shoemaker’s interest in geology began with the gift of a set of marbles from his mother in 1935, when he was seven years old. These small toys contained some unusual stones like agate, and they set him off to his first geological field trips searching his family neighborhood collecting interesting rocks.
The next summer Shoemaker traveled with his father to South Dakota’s Black Hills. The boy was so taken with the rose quartz and other minerals in the area that he gathered many samples. By the time the young Shoemaker entered fifth grade, he was being educated in Buffalo, NY, whose Museum of Science had a program that involved evening classes in sciences as diverse as mineralogy and biology. The course even used college-level textbooks. Shoemaker’s group went on field trips to a place south of Buffalo called Eighteen Mile Creek, where Shoemaker reveled in the rich trilobite collections in the Devonian rocks there.
After completing high school in Los Angeles, Shoemaker was accepted at Caltech, where he completed his undergraduate degree and where he also tried his hand as a cheerleader. He went on to Princeton for his PhD and continued with fieldwork with a search for uranium in a Northern Arizona field of old volcanoes called the Hopi Buttes. His earliest major discoveries as a geologist were deposits of uranium in the eroded volcanic vents of those long-extinct volcanoes. Shoemaker studied the impact dynamics of Barringer Meteor Crater, located near Winslow, Arizona.
To understand the dynamics, Shoemaker inspected craters that remained after underground atomic bomb tests at the Nevada Test Site at Yucca Flats. He found a ring of ejected material that included shocked quartz (coesite), a form of quartz that has a microscopically unique structure caused by intense pressure.
Shoemaker helped pioneer the field of astrogeology by founding the Astrogeology Research Program of the U.S. Geological Survey in 1961 at Flagstaff, Arizona and he was its first director. He was prominently involved in the Lunar Ranger missions to the Moon, which showed that the Moon was covered with a wide size range of impact craters. Shoemaker was also involved in the training of the American astronauts.
He himself was a possible candidate for an Apollo Moon flight and was set to be the first geologist to walk on the Moon but was disqualified due to being diagnosed with Addison's disease, a disorder of the adrenal gland. Shoemaker would train astronauts during field trips to Meteor Crater and Sunset Crater near Flagstaff. He was a CBS News television commentator on the early Apollo missions, especially the Apollo 8 and Apollo 11 missions, appearing with Walter Cronkite during live coverage of those flights. He was awarded the Wetherill Medal from The Franklin Institute in 1965.
Coming to Caltech in 1969, he started a systematic search for Earth orbit-crossing asteroids, which resulted in the discovery of several families of such asteroids, including the Apollo asteroids. Shoemaker advanced the idea that sudden geologic changes can arise from asteroid strikes and that asteroid strikes are common over geologic time periods. Previously, astroblemes were thought to be remnants of extinct volcanoes – even on the Moon.
On 16 July 1969, three of Shoemaker’s field geology students—Neil Armstrong, Buzz Aldrin, and Michael Collins—waited to begin a field excursion of their own. In a roar of millions of gallons of burning kerosene, the Saturn 5 rocket beneath them surged to life and bore the three men away from Earth. Shoemaker and his wife were at Cape Kennedy watching. Armstrong and Aldrin remained on the surface at Tranquility Base for more than two hours.
In 1993, he co-discovered Comet Shoemaker–Levy 9 using the 18" Schmidt camera at Palomar Observatory. This comet was unique in that it provided the first opportunity for scientists to observe the planetary impact of a comet. Shoemaker–Levy 9 collided with Jupiter in 1994. The resulting impact caused a massive "scar" on the face of Jupiter. Most scientists at the time were dubious of whether there would even be any evident markings on the planet.
Shoemaker spent much of his later years searching for and finding several previously unnoticed or undiscovered impact craters around the world. Shoemaker died on July 18, 1997 during one such expedition following a head on car accident while on the Tanami Road northwest of Alice Springs, Australia.
On July 31, 1999, some of his ashes were carried to the Moon by the Lunar Prospector space probe in a capsule designed by Carolyn Porco. To date, he is the only person whose ashes have been buried on the Moon. The brass foil wrapping of Shoemaker's memorial capsule is inscribed with images of Comet Hale–Bopp, the Barringer Crater, and a quotation from Romeo and Juliet reading
"And, when he shall die
Take him and cut him out in little stars
And he will make the face of heaven so fine
That all the world will be in love with night
And pay no worship to the garish sun."
The Near Earth Asteroid Rendezvous space probe was renamed "NEAR Shoemaker" in his honor. It arrived at asteroid 433 Eros in February 2000, and landed on the asteroid after a year of orbital study. He was previously honored with the asteroid 2074 Shoemaker, discovered and named by his colleague Eleanor F. Helin.