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Sarah Stewart, a scientist in planetary science at the University of California, Davis, uses instruments that can create powerful shockwaves to study planetary formation.
Credit: Copyright John D. and Catherine T. MacArthur Foundation – used with permission
It's not every day that you encounter a bona fide genius – let alone become one.
But that's exactly what happened to Sarah Stewart, scientist in planetary sciences at the University of California at Davis, when she became one of the 25 MacArthur Foundation fellows in 2018, earning $ 625,000 over five years, at his option. The fraternity has been known as the "engineering grant", although the foundation itself does not use this term.
"I was sitting where I am now at my desk, and I usually do the task of filtering identifiers, but it was a Chicago issue and I thought: Oh, Chicago, it's fun, so I'll pick up the phone, "Stewart told Space.com. [How the Moon Formed: 5 Wild Lunar Theories]
After the trio on the other end identified with the MacArthur Foundation, "I did not hear any news, because I guessed they were calling on this and it was a total surprise to me I was shocked., "she continued. (They told him that they were used to that.)
The Stewart Award rewards her extensive research as a global scientist who, she says, has been inspired by reading science fiction novels and spreading "Star Trek" with her father. At the university, she specialized in astrophysics and decided to focus on the formation of the planet.
But instead of choosing a particular problem to solve, she ended up cracking for a technique – shock compression experiments, which use a large airgun to mimic conditions in giant space collisions. "I am one of those scientists who roam the solar system," Stewart said. "Nobody grows up thinking that he's going to run guns for a living, so it's a bit of a fluke, does not it?"
Stewart has access to two firearms, measuring 40 and 25 mm, in her own institution, and has found ways to access even more powerful facilities at the Lawrence Livermore and Sandia National Laboratories (both facilities are managed by the US Department of Energy.) These machines are powerful enough to expose the mineral samples to incredibly violent pressures – conditions as extreme as those of Jupiter's heart – long enough for scientists to measure what is happening to inside.
Shock compression experiments act as a sort of time machine. They bring Stewart and his colleagues back to observe these early solar system events from the comfort of the laboratory. His most famous research is on what happened during the formation of our moon.
The experiments are only a little less stressful than the initial impact could have been, she said. "Shooting the weapon is a high drama," Stewart said. "It's a lot of planning and preparation for a hint of terror." However, when things are going well, experiments can produce extremely intriguing data, such as the results that led Stewart and his colleagues to revise the main idea of scientists about the formation of the moon.
The current main competitor to explain the moon suggests that it broke when a Mars-sized body collided with the primitive Earth. But this explanation has a serious drawback: the Earth and the Moon are chemically almost identical, which can not be explained by the impact unless two identical bodies meet. [The Moon: 10 Surprising Lunar Facts]
"All that everyone assumes about this step is wrong," said Stewart, herself and her graduate student, Simon Lock, have realized looking at the results of this initial experience.
The results of Stewart 's collision suggest an explanation that perfectly avoids this problem: the giant impact did not cause the moon break. Instead, the two objects vaporized and turned into a fugitive but gigantic donut-shaped phenomenon that the team dubbed a synestia. Both the Earth and the Moon have settled outside of this theorized but never seen body, identical compositions intact.
"What we understood was that the Earth did not really look like a planet anymore," Stewart said. "When we saw this for the first time and understood that it had changed the way the moon would form, we called it the disc that would not fall."
It took the research team four years to incorporate the results into a document that she felt comfortable publishing. Scientists continue to tinker with the game after the game that's over with Earth and Moon, and Stewart does not intend to abandon this conversation despite his recent windfall .
"I love my day job, I will not leave my day job," Stewart said. In addition to unlocking the secrets of the moon, she also wants to tackle other issues, such as studying parts of the Earth's mantle that could be unchanged since the giant impact. She compared the process to making a marble cake, leaving behind the original recipe that can still be studied.
But she said the scholarship would give her more flexibility to be creative, as part of her research and beyond. "The promise is just to make it new and exciting and that's it," said Stewart. "It's the only rope I put on it."
Email Meghan Bartels at [email protected] or follow her. @meghanbartels. follow us @Spacedotcom and Facebook. Original article on Space.com.
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