Carolyn Shoemaker, Hunter of Comets and Asteroids, Dies at 92
Carolyn Shoemaker, who for more than a decade managed a telescopic camera with her husband from a high-altitude observatory in California and …
Carolyn Shoemaker, who for more than a decade managed a telescopic camera with her husband from a high-altitude observatory in California and became widely regarded, without academic training, as the world’s foremost detector of comets and asteroids, died on Aug. 13 at a hospital in Flagstaff, Ariz. She was 92.
Her health had deteriorated after a fall a week earlier, her daughter Linda Salazar said.
Ms. Shoemaker’s career as a professional stargazer began when she was around 50, after Ms. Salazar, her youngest child, left for college. To fill the time, Ms. Shoemaker sought a “strong compelling interest,” she wrote in an autobiographical essay.
In spite of feeling nervous around scientific instruments as simple as a calculator, she offered to help her husband, the revered planetary geologist Eugene Shoemaker, with a project gathering data on comets and asteroids.
Dr. Shoemaker believed that collisions with Earth by comets had been responsible for transporting to the planet water and other elements necessary for life, meaning that humans “may truly be made of comet ‘stuff,’” Ms. Shoemaker wrote in her essay. Dr. Shoemaker also worried that a comet hitting Earth could threaten human civilization. Yet relatively little scientific attention had been paid to the frequency and effects of cometary collision with planets.
As the dark phase of the lunar cycle began, making it easier to see faint objects in outer space, the Shoemakers would travel to an observatory on Palomar Mountain near San Diego. To locate previously unknown comets and asteroids, they aimed to photograph as much of the night sky as possible. The chirping of birds signaled bedtime.
In the afternoons, Dr. Shoemaker would take the film they had used the previous night and develop it in a darkroom, then turn over the negatives to Ms. Shoemaker. Using a stereoscope, she would compare exposures of the same block of sky at different times. If anything moved against the relatively fixed background of stars, it would appear to float in the viewing device’s eyepiece.
Ms. Shoemaker was charged with discerning what was the grain of the film (and perhaps dust on it) and what was an actual image of light emitted by an object hurtling through space. “With time,” she wrote, “I saw fainter and fainter objects.”
It took a few years before she found her first new comet, in 1983. By 1994, in addition to hundreds of asteroids, she had discovered 32 comets, a number considered by the United States Geological Survey and others to represent the world record at the time.
That year also occasioned a discovery so exceptional that it inspired what was probably the only moment in her life when Ms. Shoemaker drank champagne straight from the bottle.
One comet, known as Shoemaker-Levy 9 (named in part for their associate David Levy), had stood out from the rest. Rather than making a lonely journey through the cosmic vacuum, Shoemaker-Levy 9 was on a collision course with Jupiter. By detecting the comet shortly before impact, Ms. Shoemaker gave scientists an opportunity to examine whether or not comets slamming into planets represented major astronomical events — and to test the hypotheses of her husband’s work.
The result had all the drama the Shoemakers might have imagined: whirling fire balls, a plume of hot gas as tall as 360 Mount Everests and a series of huge wounds that appeared in Jupiter’s atmosphere. Amateur astronomers could witness much of it with store-bought telescopes.
Anticipation of Shoemaker-Levy 9 and the spectacular show it produced made the front page of The New York Times and the cover of Time magazine, which called the Shoemakers “a husband-and-wife scientific duo who spend their evenings scanning the skies for heavenly intruders.” The couple and Mr. Levy were featured in a Person of the Week segment of the nightly ABC News broadcast and met with President Bill Clinton and Vice President Al Gore.
“It definitely showed that cometary impact could play a role in shaping the solar system,” Priyamvada Natarajan, an astronomy professor at Yale, said in a phone interview. “It’s a key part of the puzzle of the origins of chemical compounds and life.”
The event also demonstrated the value of Ms. Shoemaker’s expertise in comet detection.
“Carolyn Shoemaker is one of the most revered and respected astronomers in history,” Jennifer Wiseman, a senior scientist overseeing the Hubble Space Telescope, said in a phone interview. “Her discoveries, her tenacious care in how she did her work — those things have created a legacy and a reputation that has inspired people who have come into the field after her.”
Carolyn Jean Spellmann was born on June 24, 1929, in Gallup, N.M. She grew up in Chico, Calif., where her father, Leonard, and her mother, Hazel (Arthur) Spellmann, ran a chicken farm.
She obtained a master’s degree in history and political science from Chico State University (now known as California State University, Chico). She met Eugene Shoemaker at her brother’s wedding, where Dr. Shoemaker, her brother’s former college roommate, served as best man. They married a year later, in 1951.
Ms. Shoemaker worked briefly as a schoolteacher after college, but by the time she married she had quit working. She accompanied her husband on field expeditions, cooked meals for him and his colleagues and raised the family’s three children.
Today, professional astronomers use remotely controlled telescopes and digital detection software. They tend not to pull all-nighters in remote mountain regions, guiding telescopes across the night sky and developing film in their own darkrooms, as the Shoemakers did. Yet scientists still depend on methods that Ms. Shoemaker perfected.
“She and her colleagues set the stage for how to identify what we would call minor bodies in our solar system, such as comets and asteroids,” Dr. Wiseman said. “We still use the technique of looking for the relatively fast transverse motions of comets and asteroids in our own solar system as compared to the slower or more fixed position of stars.”
In addition to Ms. Salazar, Ms. Shoemaker is survived by another daughter, Christine Abanto; a son, Patrick; three grandchildren; and five great-grandchildren.
In 1997, she and Dr. Shoemaker were on a trip to Australia investigating craters when, driving on a remote outback road, they rounded a corner and collided with an oncoming car. Ms. Shoemaker broke her rotator cuff and fractured a rib and wrist. Dr. Shoemaker died instantly.
After her husband’s death, Ms. Shoemaker dedicated herself to finishing the research they had started.
“Without Gene, I would never have known the excitement of planetary science,” she wrote in her autobiographical essay. “Without me, he often said, his search for asteroids and comets and then the Australian cratering work would never have been attempted. Together, we could do more than either of us alone.”