Extremophiles and Exoplanets: Expanding the Potentially Habitable Real Estate in the Galaxy

Professor Jill Tater
21 July, 2009

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We discovered the very first planetary worlds in orbit around a body other than the Sun in 1990. They were small bodies (0.02, 4.3 and 3.9 times as massive as the Earth) and presented a puzzle because they orbit a neutron star (the remnant core of a more massive star that had previously exploded as a supernova) and it was not clear whether these bodies survived the explosion or reformed from the stellar debris. They still present a puzzle, but today we know of more than 300 planetary bodies in orbit around hundreds of stars in the prime of their life cycle. Many of these planets are more massive than Jupiter, and some orbit closer to their stars than Mercury around the Sun. To date we have not found another planetary system that is an exact analog of the Earth (and the other planets of our solar system) orbiting a solar-type star, but we think that is because we have not yet had the right observing instruments. Those are on the way! In the next decade, we should know whether other Earth mass planets are plentiful or scarce.

At the same time that we have been developing the capabilities to detect distant Earths, we have also been finding that life on Earth occurs in places that earlier scientists would have considered too hostile to support life. Scientists were wrong. We now know that extremophiles can exist (and sometimes thrive) in the most astounding places; at the bottom of the ocean around hydrothermal vents, in ice, in pure salt, in boiling acid, and irradiated by massive doses of UV and X-rays. There do appear to be places on Earth that are too dry for even these (mostly microbial) extremophiles, or perhaps our sensors aren’t yet sensitive enough to find them.

Since life-as-we-know-it is so extraordinarily hardy, might it exist today (or in the past) on any of the exoplanets that are being found? A group of scientists known as astrobiologists are trying to answer that question. This lecture will discuss what appears to be possible in the near future, as well as the questions that will likely remain unanswered until new technologies enable new explorations in the more distant future. It might even turn out that our first indication of another inhabited world will be the signals deliberately generated by its inhabitants – that’s right, SETI

Jill Tarter holds the Bernard M. Oliver Chair for SETI (Search for Extraterrestrial Intelligence) and is Director of the Center for SETI Research at the SETI Institute in Mountain View, California. She served as Project Scientist for NASA’s SETI program, the High Resolution Microwave Survey, and has conducted numerous observational programs at radio observatories worldwide. Since the termination of funding for NASA’s SETI program in 1993, she has served in a leadership role to secure private funding to continue the exploratory science. Currently, she serves on the management board for the Allen Telescope Array, a joint project between the SETI Institute and the UC Berkeley Radio Astronomy Laboratory.

Tarter’s work has brought her wide recognition in the scientific community, including the Lifetime Achievement Award from Women in Aerospace, two Public Service Medals from NASA, Chabot Observatory’s Person of the Year award (1997), Women of Achievement Award in the Science and Technology category by the Women’s Fund and the San Jose Mercury News (1998), and the Tesla Award of Technology at the Telluride Tech Festival (2001). She was elected an AAAS Fellow in 2002 and a California Academy of Sciences Fellow in 2003. In 2004 Time Magazinenamed her one of the Time 100 most influential people in the world, and in 2005 Tarter was awarded the Carl Sagan Prize for Science Popularization at Wonderfest, the biannual San Francisco Bay Area Festival of Science.

Tarter is deeply involved in the education of future citizens and scientists. In addition to her scientific leadership at NASA and SETI Institute, Tarter has been the Principal Investigator for two curriculum development projects funded by NSF, NASA, and others. The first, the Life in the Universe series, created 6 science teaching guides for grades 3-9 (published 1994-96). Her second project, Voyages Through Time, is an integrated high school science curriculum on the fundamental theme of evolution in six modules: Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution and Evolution of Technology (published 2003). Tarter is a frequent speaker for science teacher meetings and at museums and science centers, bringing her commitment to science and education to both teachers and the public. Many people are now familiar with her work as portrayed by Jodie Foster in the movie Contact.

Co-presented with the Professor Harry Messel International Science School (ISS) as part of the International Year of Astronomy

International Science School