Lecture Starts at 17:25
www.pswscience.org
PSW #2471
February 3, 2023
Whispers from Other Worlds: NASA's Search for Life in the Cosmos
Thomas Zureichen (NASA, ret.)
Nadia Drake (Science Journalist)

Whether life exists beyond Earth is among the most exciting — and toughest — mysteries that science can solve. For millennia, humans have wondered whether we are alone in the cosmos, but those musings lived almost exclusively in the realm of philosophy, not science. Sixty years ago, the first scientific search for extraterrestrial technologies was met with curiosity, and at times cynicism and ridicule. Only recently has the search for extraterrestrial intelligence (“SETI”) begun to gain traction and legitimacy among scientists.

Looking for life beyond Earth is now a core motivator and organizing principle for NASA’s science programs. This lecture will first frame the discussion of looking for extraterrestrial life in the context of the famed 1961 Drake equation, a framework that connects physical, chemical and biological processes with the development of detectable civilizations within our own galaxy. And, though the Drake equation’s original form has survived unchanged, we will highlight some changes in our understanding and definition of the equation’s variables – modifications that are a direct result of our growing understanding of life’s tenacity on our home world.

The lecture will discuss three ways in which NASA’s Science program focuses on identifying signatures of life elsewhere in the universe.

First, by looking at exoplanets (worlds orbiting other stars). Estimates of life’s possible footholds on these worlds are informed by statistical results from space-based missions and detailed spectroscopic observations of planetary atmospheres. This part of the lecture is particularly timely and relevant as we are just getting the first exoplanet spectra from the James Webb Space Telescope, and starting technology development that will enable the Habitable Worlds Explorer, NASA’s next astrophysics flagship mission, designed specifically to study exoplanet atmospheres and to detect possible signatures of life in their spectra.

Second, moving closer to home, NASA’s science program is focused on icy ocean worlds in our own solar system. Whether it is about gaining knowledge of planetary building blocks, or visiting bizarre worlds such as Titan and Europa — moons of Saturn and Jupiter, which might harbor life today — NASA is seeking to gain insights into processes that transcend the boundaries of our own world, and might have given rise to biology elsewhere.

Third, the lecture will focus on Mars, our near-Earth companion. We have a twenty-year-long history of sending rovers to the Martian surface, and together with landers and orbiters to Mars, we have learned that although the planet is harsh and inhospitable by our standards today, it was once warmer and wetter — a place with considerably more promise for lifeforms to evolve and thrive, either on or below its surface, albeit billions of years ago. This research is culminating in the Mars Sample Return, humankind’s first round-trip to another planet, with the goal of delivering curated samples to the best laboratories on Earth.

Finally, the lecture will address NASA’s effort to define the search for techno-signatures — signs of intelligent alien civilizations. While most of these searches have historically targeted radio emissions, the search today has broadened considerably.

Thomas H. Zurbuchen, known in the space community as “Dr. Z,” is the longest continually serving Head of Science at NASA, a post he held from October 2016 through the end of 2022. As NASA Associate Administrator for the Science Mission Directorate, he was responsible for all aspects of NASA leadership in space science. During his tenure NASA launched 37 science missions and stated 54, including the James Webb Space Telescope, two Mars landings, the Ingenuity helicopter, the Parker Solar Probe, and the DART mission. Thomas also conceived and led the Earth System Observatory, an advanced multi-platform observatory that creates a 3D holistic view of the Earth, from bedrock to atmosphere.

Nadia Drake is a freelance science journalist and contributing writer at National Geographic. She specializes in covering astronomy, astrophysics and planetary science, as well as anything involving jungles and spiders. Her byline has also appeared in The Atlantic, Nature, The New York Times, Science News, Wired, and Scientific American, for which she recently led coverage of NASA’s Artemis I moon mission.

www.pswscience.org