LOS ANGELES – The data was like nothing Margaret Kivelson and her team of physicists ever expected.
It was December 1996, and the spaceship Galileo had just flown from Europe, a frosty Jupiter's moon. The readings reflecting back to Earth pointed to a magnetic field emanating from the moon. Europe should not have a magnetic field, but there it was – and not even in the right direction.
"That's unexpected," she recalled as the strange dates came in. "And that's wonderful."
It would be the most significant of a series of surprises from the Jupiter moons. For Kivelson's team, the mission should not have been so exciting.
She and her colleagues had developed the magnetometer that returned the anomalous data. The task of the instrument was to measure Jupiter's massive magnetic field and all variations of its moons. These results are likely to interest space physicists, but few others.
In other words, Kivelson's instrument should never change the course of space exploration.
And then it did too. Kivelson and her team would soon prove that they had discovered the first subsurface, the saltwater ocean, in another world.
Kivelson, who turns 90 this month, is Professor Emeritus of Space Physics at the University of California, Los Angeles. For 40 years she has been actively involved in almost every NASA journey beyond the asteroid belt. She has a dry sense of humor, and her modesty belies the extent of her scientific achievements.
Her team changed the way magnetometers are used in space missions and made them an indispensable tool of discovery. As a result, the outer solar system is now a hot zone in search of habitability.
More recently, Kivelson was an investigator working on the plasma instrument for the Europa Clipper, NASA's next big journey to the outer solar system. The spaceship is scheduled to launch in 2022 and investigate the habitability of Europe, Jupiter's ocean moon. Kivelson's work, among other things, by determining the depth and salinity of the ocean, will help to answer the question of whether life could be there.
The story began with Galileo's unusual encounters with Jupiter's moons in the mid-1
Harvard and Hydrogen
Kivelson was born in New York City. Her father was a doctor. Her mother was a teacher. Margy, as her friends call her, was an early mathematician.
"I liked it," she said. "I thought it was one of the easier topics, and I knew that was not commonplace."
She was picked up at Harvard, which sent women to Radcliffe College – a separate school with no faculty. Harvard professors would go through the commons to repeat their lectures to the women. "Women were not invited to the Harvard classrooms," she said.
There she found physics that allowed her to use mathematics in such a way that answers needed to be physically meaningful.
1955 She joined the RAND Corp. at, a company founded to provide research to the Department of Defense, including nuclear weapons research. She was commissioned to work on an equation describing the state of hydrogen at a pressure equivalent to 1 million Earth atmospheres.
"There are two places where hydrogen gets into this kind of pressure," she said. "One of them is in a hydrogen bomb, and the other is in the middle of Jupiter."
Her background in theoretical physics and her final expertise in celestial science brought her to UCLA in 1967. Her RAND research made her the local expert on Jupiter, and she soon became known in space physics for her theoretical work on some of the most basic ideas in the field.
Field Research Brings Discovery
When NASA announced what the Galileo mission should be Jupiter, Kivelson was well positioned to propose a magnetometer.
"I was very immersed in the science that was already available in terms of Jupiter's magnetic field and particle environment," she said.
Galileo entered orbit around Jupiter in 1995. The first major discovery by Kivelson and her team was an inner magnetic field on Ganymede, Jupiter's largest moon.
Carol Paty, an Associate Professor of Earth Sciences at the University of Oregon, said nobod Man expected an object that was so small and cold that it had the chemistry, thermodynamics, and structure necessary to create its own magnetic field to create.
"His discovery has transformed the scientific understanding of the inner workings of planetary bodies"] Then came the series of encounters between Europe and Galileo.
Geologists had suspected that the ice moon once had an underground ocean, but could not tell if it was frozen or solid long ago. That would still be a mystery, were it not for the anomalous data that the Galileo magnetometer would have received.
Something strange happened, and Kivelson and her perplexed team worked out several explanatory paths. One of these ideas was that Europe's magnetic field was induced by Jupiter.
The thinking was that as Europe moves through Jupiter's magnetic field, a current flows through an underground conductor of some sort on the moon, creating a miniature magnetic field. That's what triggered the Galileo Metal Detector.
With Europe sometimes beyond Jupiter and sometimes below, the magnetometer team needed measurements from both sides.
When the magnetic field of the moon changed the direction on the other side The field was induced by Jupiter – and therefore had an inner conductor. The only thing that would fit the bill would be a subsoil, saltwater ocean.
A Galileo fly-by in January 2000 found exactly what Kivelson's team had predicted: definitive evidence of a global ocean on Europe.
One of the most fundamental discoveries ever made in planetary science, "said Louise Procker, director of the Lunar and Planetary Institute in Houston," It really has created a revolution. "
Robert Pappalardo, the project scientist of the outstanding ones NASA's Europe Clipper mission said the discovery had implications for the entire solar system.
"It really swung the pendulum toward the plausibility of the oceans in icy worlds. … & # 39; & # 39; he said. "The ocean world did not even exist then, now it's a class of objects, thanks to Margie's basic work."
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