Loeb Lectures: Sara Seager (MIT)


Monday, November 1, 2021, 4:30pm

All lectures will be held in Jefferson 250
And also streamed live via Zoom (but we hope you will attend in person, with appropriate face covering)
For Zoom link, please contact Jolanta Davis

Monday, November 1, 4:30pm:
"Exoplanets and the Search for Atmospheric Biosignature Gases"
Thousands of exoplanets are known to orbit nearby stars and small rocky planets are established to be common. The ambitious goal of identifying a habitable or inhabited world appears within reach. But how likely are we to succeed? We need to first discover a pool of planets in their host star’s “extended” habitable zone and second observe their atmospheres in detail to identify the presence of water vapor, indicative of surface liquid water, a requirement for all life as we know it. Life must not only exist on one of those planets, but the life must produce “biosignature gases” that are spectroscopically active and detectable with ground- or space-based telescopes. We need to be able to sort through a growing list of false-positive scenarios with what is likely to be limited data. What will it take to identify such habitable worlds, amidst a yet unknown range of planetary environments, with the observations and theoretical tools available to us?

Tuesday, November 2, 4:30pm:
"Venus as Potentially Habitable Planet"
Scientists have been speculating on Venus as a habitable world for over half a century, based on the Earth-surface-like temperature and pressure in Venus’ clouds at altitudes 48-60 km above the Venus surface. The recent and controversial detection of phosphine gas in the atmosphere of Venus has renewed interest in both the Venus atmosphere in general and in the speculative possibility of life in the clouds. Any life would have to persist aloft indefinitely against downward gravitational settling, in order to avoid the destructively hot temperatures beneath the clouds. Recent efforts to re-analyze and re-interpret the decades’ old legacy data collected by both NASA’s Pioneer Venus and Russia’s Venera missions has further highlighted intriguing non-equilibrium chemistry. Professor Seager will discuss the latest on Venus as a potentially habitable planet.

Wednesday, November 3, 4:30pm:
"The Search for Another Earth"
For thousands of years people have wondered, “Are there planets like Earth?” “Are such planets common?” “Do any show signs of life?” Today astronomers are poised to answer these ancient questions, having recently found thousands of exoplanets that orbit nearby stars. However, another Earth—an Earth-sized planet in an Earth-like orbit about a Sun-like star—is an incredibly challenging type of planet to detect and identify, largely because an Earth’s reflected starlight signal is ten billion times fainter than the host star it is adjacent to. A half-century old idea, the Starshade, works with diffraction to suppress starlight to these unprecedented levels of planet-star “contrast” and is ready to be implemented as a new kind of space telescope mission. Professor Seager will address the prospects and challenges to find another Earth with Starshade and other methods.

Sara Seager is an astrophysicist and a Professor of Physics, Professor of Planetary Science, and a Professor of Aeronautics and Astronautics at the Massachusetts Institute of Technology where she holds the Class of 1941 Professor Chair. She has been a pioneer in the vast and unknown world of exoplanets, planets that orbit stars other than the sun. Her ground-breaking research ranges from the detection of exoplanet atmospheres to innovative theories about life on other worlds to development of novel space mission concepts.

In space missions for planetary discovery and exploration, she was the Deputy Science Director of the MIT-led NASA Explorer-class mission TESS; she was PI of the JPL-MIT CubeSat ASTERIA; is a lead of the Starshade Rendezvous Mission (a space-based direct imaging exoplanet discovery concept under technology development) to find a true Earth analog orbiting a Sun-like star; and most recently is directing a mission concept study to find signs of life or life itself in the Venus atmosphere.

Her research earned her a MacArthur “genius” grant and in addition Professor Seager is a member of US National Academy of Sciences, a recipient of the Sackler Prize in the Physical Sciences, and has been awarded one of Canada’s highest civilian honors, an Officer of the Order of Canada. Professor Seager is the author of, “The Smallest Lights in the Universe: A Memoir”.

The lectures are sponsored by the Morris Loeb Lectureship Fund.

See also: Loeb