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SETI Talks: A Rainbow of Exoplanets

December 16, 2020 @ 7:00 pm - 8:00 pm

What colors are the worlds orbiting other stars? How does color help us in our search for life beyond Earth?

We identified an exoplanet color for the first time in 2013: HD 189733b, a Jupiter-like exoplanet was determined to be dark-blue. Since then, astronomers have discovered more than 4,000 exoplanets and found out that a significant fraction of them are terrestrial. After detecting them, the next challenge is to image them, which will reveal their color. So what is the color of a lifeless terrestrial exoplanet? Will it be red because of rust like Mars, or blueish-white because of clouds in the atmosphere like Venus in visible light? Among the 300 million potentially habitable planets in our galaxy, can we expect that more than one will indeed host a type of life? What will be the impact of this life on their colors? Can we expect this planet to have the same vegetation as our Earth? What colors are associated with the presence of microbiological activity on the surface of a planet? What do a planet’s colors tell us about habitability on its surface? Astronomers predict that one day we will see the color of an Earth-like exoplanet.To answer these questions, we invited two scientists from different backgrounds to our SETI Talk.

Angelle Tanner, associate professor at Mississippi State University who is interested in finding habitable planets outside our solar system and will tell us about the vegetation of exoplanets and the technology we could one day use to see an exoplanet.

Ivan Paulino-Lima, biologist at Blue Marble Institute of Science, is interested in extremophiles and leads microbiological experiments in satellites around Earth and is involved in research on the colors of bacteria.Franck Marchis, planetary astronomer at the SETI Institute, will moderate the discussion and help by bringing more colors of the rainbow to this topic.

Dr. Angelle Tanner is an Associate Professor in the Department of Physics & Astronomy at Mississippi State University. She has been interested in exploring alien planets since she was young. Her research focuses on multiple extrasolar planet detection methods, including using radial velocities, astrometry and direct imaging. She also studies the properties of the stars around which we are looking for planets. These properties include a star’s size, rotational velocity, activity and whether it has a dusty debris disk. By knowing the architecture of planetary systems and the properties of their host stars, we also learn more about how those planets formed and evolved and how many similar systems exist in our Galaxy. She is currently developing the Starchive, an open-access database of nearby stars, which will be used by many upcoming extrasolar planet discovery programs, including JWST, TESS, Kepler, LSST and WFIRST. Dr. Tanner hopes to be a primary contributor to the inevitable discovery of life on a nearby, Earth-like planet.

Dr. Ivan Paulino-Lima is a research scientist at the Blue Marble Space Institute of Science (BMSIS). He is interested in extremophiles and their adaptations to the environment. At Ames Research Center, he joined Dr. Rothschild’s lab. They have isolated a wide range of radiation-resistant microorganisms and are now characterizing the molecular mechanisms related to radiation resistance. They used the microbial collection to build a reflectance spectra database that will help astronomers look for biosignatures on exoplanets. He is currently responsible for microbiology experiments in a satellite mission at Earth’s orbit, testing microbial performance under three different gravity regimes. Field experience includes trips to the Atacama Desert (Chile), Sonoran Desert (Arizona), Mount Saint Helens (Washington), Kali Crater (Estonia), Kilauea Volcano (Hawaii), and Death Valley (California).


December 16, 2020
7:00 pm - 8:00 pm
Event Category:


SETI Institute