In this series of posts, we sit down with a few of the keynote speakers of the 233rd AAS meeting to learn more about them and their research. You can see a full schedule of their talks here!
96% of our universe is “dark” — that is, made of…stuff…that does not interact with light, meaning we can’t see it. The atoms that make up you, your house, all of the stars in all the galaxies, and even the device you’re using to read this post comprise a mere 4% of all of the matter and energy in the universe. Of this unknown 96%, about a quarter is believed to be made of dark matter, named such because it exerts gravitational forces like matter (as far as we can tell), but it does not interact with light. Aside from this, astronomers know little else about this mysterious matter. If that sounds like a major problem to you, then you’re right! Fortunately, we have scientists like Dr. Elena Aprile on the case.
Dr. Aprile is a professor at Columbia University and the 2019 winner of the AAS Berkeley prize. Her research career began as a summer student at CERN, where she worked with Nobel-winner Carlo Rubbia on high energy physics. She extended her stay beyond the summer after Rubbia submitted a paper on the feasibility of using liquid argon to study neutrinos. And she hasn’t looked back since. She completed her graduate degree in Geneva, Switzerland and then moved to Harvard to continue working with Rubbia as a postdoctoral researcher on the seeds of what eventually became Fermilab’s neutrino program. She obtained a position at Columbia University as the physics department’s first female faculty member, where she has broken down barriers ever since. Notably, her first successful NASA grant came just months after she gave birth to her first daughter. She recalled that the men in the department at the time were “totally shocked that a woman could be pregnant and do other things at the same time.”
Dr. Apile continued her passion for noble liquid detectors at Columbia by starting the XENON project, an experiment deep underground beneath the Gran Sasso mountain in Italy that aims to directly detect dark matter. XENON, as its name suggests, is a liquid xenon experiment that searches for the tiny nudges of xenon atoms that happen when a dark matter particle interacts with the detector. Dr. Aprile has been involved since the beginning, submitting the original proposal and evolving with the collaboration through its upgrades and iterations. The latest iteration was called XENON1T, which is modestly named, as it actually used a whopping 3.5 tons of liquid xenon!
XENON1T is officially no more, shutting down last month to undergo upgrades. On the other side (later this year) it will emerge as XENONnT, an eight-ton liquid xenon detector designed to reach sensitivity to the solar neutrino background. Dr. Aprile says it is frustrating that dark matter has not yet been detected, but that “the excitement of challenges keeps driving [her] forward.” She’s also thankful for all the people who work with her, as they keep her driving forward as well.
To undergraduates, Dr. Aprile says to follow your instincts and be determined. Research is hard, so it’s important to find something that excites you. She also stressed the importance of finding a good mentor. In particular, a good mentor can help you find confidence as researcher if that is something you struggle with, as well as in other areas essential for a career in academia.
If you’re interested in hearing more about Dr. Aprile’s work, check out her plenary talk at 4:30pm on Thursday, January 10th at #AAS233!