After the Prize(1)

random walk TRACKING DOWN THE “MISSING” CARBON FROM THE MARTIAN ATMOSPHERE Building Mars is blanketed by a mostly carbon says Renyu Hu, a postdoctoral scholar their nuclei but different numbers of dioxide atmosphere—one that is far too at JPL, a visitor in planetary science at neutrons, and thus different masses. thin to prevent large amounts of water on Caltech, and lead author on the paper Comparing measurements from martian I’m always surprised Powerful the surface of the planet from subliming that appeared in Nature Communications. meteorites to those recently collected by or evaporating. But many researchers When considering how the early NASA’s Curiosity rover, they found that and delighted by the Magnetic have suggested that the planet was once atmosphere might have transitioned to the atmosphere is unusually enriched in shrouded in an atmosphere many times its current state, there are two possible carbon-13. To explain that, they describe ways in which we expand Fields thicker than Earth’s. For decades that mechanisms for the removal of excess a mechanism involving a photochemical left the question, “Where did all the carbon dioxide (CO2). Either the CO2 cascade that produces carbon atoms that our understanding. carbon go?” was incorporated into minerals in rocks have enough energy to escape the atmo- Now scientists from Caltech and called carbonates or it was lost to space. sphere, and they show that carbon-12 is When certain massive stars use up A visualization of the strong, ordered magnetic JPL think they have a possible answer. A separate study coauthored by far more likely to escape than carbon-13. all of their fuel and collapse onto feld built up by dynamo action in the core of The team suggests that 3.8 billion years Bethany Ehlmann, assistant professor of “With this mechanism, we can their cores, explosions 10 to 100 times a rapidly rotating, collapsed star. ago, Mars might have had only a moder- planetary science at Caltech, used data describe an evolutionary scenario for brighter than the average supernova ately dense atmosphere. The researchers from several Mars-orbiting satellites to Mars that makes sense of the apparent occur. Astrophysicists from Caltech, have identiﬁed a photochemical process inventory carbonate rocks, showing that carbon budget, with no missing process- UC Berkeley, the Albert Einstein causing its outer edge to rotate faster that could have helped such an early there are not enough carbonates in the es or reservoirs,” says Ehlmann, who is Institute, and the Perimeter Institute than its center. However, no previous atmosphere evolve into the current thin upper crust to contain the missing carbon also a coauthor on the Hu study. —KF for Teoretical Physics have used models could prove this process could one without creating the problem of from a very thick early atmosphere. the National Science Foundation’s strengthen a magnetic feld to the extent “missing” carbon. To study the escape-to-space Blue Waters supercomputer to needed to collimate a jet, largely because “With this new mechanism, every- scenario, scientists examined the ratio Insider Info perform three-dimensional computer these simulations lacked the resolution to thing that we know about the martian of carbon-12 and carbon-13, two stable simulations to fll in an important resolve where the fow becomes unstable. atmosphere can now be pieced together isotopes of the element carbon that Former E&S editor Doug Smith contributed Whether we’re missing piece of our understanding Lead author on the paper Philipp into a consistent picture of its evolution,” have the same number of protons in to more than of what drives these blasts. Mösta—who started the work while a issues of the contemplating the frst In the past, scientists have postdoctoral scholar at Caltech and is magazine prior to simulated the evolution of massive now a NASA Einstein Fellow at UC his retirement in moments of the universe, stars from their collapse to jet-driven Berkeley—and his colleagues developed November 2015. explosions by factoring unrealistically a simulation of a rapidly rotating TRIPLE THREAT the fundamentals of large magnetic felds into their collapsed stellar core and scaled it so Te public high school in Blue Springs, Missouri, just outside Kansas City, models—without explaining how they that it could run on the Blue Waters graduates more than 500 seniors each year. Remarkably, the valedictorian in 85 life here on Earth, could be generated in the frst place. supercomputer, known for its ability to 2015 was the younger sister of the valedictorian in 2014—who was the younger “Tat’s what we were trying to provide sustained high-performance sister of the valedictorian in 2013. alumni, Arthur McDonald personalized medicine, understand with this study,” says computing for problems that produce And all three are now Caltech undergraduates. (PhD ’70) and Ian Agol Luke Roberts, a NASA Einstein large amounts of information. Te team’s Tese are the Butkovich sisters: junior Slava and sophomore Nina, both or the capability of the Fellow at Caltech and a coauthor on highest-resolution simulation took 18 majoring in chemical engineering, and freshman Lazarina (“Laza”), currently (BS ’92), have been named a paper reporting the team’s fndings days of around-the-clock computing deciding between chemical engineering and chemistry. recipients of 2016 Breakthrough phone in your pocket— in the journal Nature. “How can you by about 130,000 computer processors Te sisters represent “a three-peat,” says Caltech admissions director Prize awards. Read about previous start with the magnetic feld you might to simulate just 10 milliseconds of the Jarrid Whitney, not a package deal. “All our applicants are reviewed Caltech winners on page 24. science continues to expect in a massive star that is about to core’s evolution. independently and without regard to siblings, parents, or other legacies. 2 collapse—or at least an initial magnetic In the end, the researchers For three family members to receive consecutive ofers of admission indicates transform our lives on feld that is much weaker than the feld were able to simulate the so-called how tremendously talented all three of them must be.” required to power these explosions— magnetorotational instability responsible For their part, Slava, Nina, and Laza (pictured right to left, below) fnd a daily basis.” and build it up to the strength that for the amplifcation of the magnetic their own nearly identical trajectories Sports Illustrated dedicated nearly you need to collimate a jet and drive feld. As theory predicted, they saw that unsurprising. “We were taught at a — France A. Córdova (PhD ’79), director of a jet-driven supernova?” the instability creates small patches young age that science majors can do the National Science Foundation, in an For more than 20 years, theory of an intense magnetic feld distributed a lot of good for society,” Slava says. interview with Ben Tomlin of the Caltech Alumni Association. has suggested that the magnetic feld throughout the core of the collapsed In fact, according to all three, of the innermost regions of a massive star. Tey found that a dynamo process one of the biggest challenges since star that has collapsed, also known as a connects those patches and generates leaving high school has been learning proto-neutron star, could be amplifed currents that amplify the magnetic felds, to rely on something they had words to a story on the recent successes of by an instability in the fow of its turning them into the kind needed to honestly never needed before now: 7,000the Caltech men’s basketball team. Learn more plasma if the core is rapidly rotating, power jets. —KF study groups. —DZ about our stellar student athletes on page 18. 6 ENGINEERING & SCIENCE SPRING 2016 SPRING 2016 ENGINEERING & SCIENCE 7.

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