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How to Spot a Pale Blue Dot in the Night Sky - Signatures of Life on Extrasolar Planets |
Dr. Lisa Kaltenegger |
Thursday, Oct 11, 2007 at 8:00 PM |
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"It is only a matter of time before astronomers find an Earth-sized planet orbiting a distant star. When they do, one of the first questions we will ask is if it is habitable. Is there life? When we take a low resolution spectral picture of the planet, what can we tell? The spectral fingerprint of an Earth-like planet changes throughout its evolution. Frame 1: Jurrasic park on a Sunday afternoon, Earth’s atmosphere consists of about three-fourths nitrogen and one-fourth oxygen, with a small percentage of other gases like carbon dioxide and methane. Frame 2: Steamy atmosphere, an ocean is covering the entire planet, no oxygen is present, timeline about four billion years ago. Can we tell the difference of what we see on a planet far away? Can we tell from a few photons of light if it is habitable? If there are bacteria or dinosaurs roaming around? Finding Earth-like planets around other stars is a fascinating endeavor. We are the explorers, who will get that first look at planets far away and maybe… also a pale blue dot in the night sky."
This month we are happy to welcome Dr. Lisa Kaltenegger, astrophysicist from the Harvard-Smithsonian Center for Astrophysics. Her research is focused on the search for extrasolar planets and the simulation of detectable planetary atmospherics. Dr. Kaltenegger and her colleagues have built a model of Earth’s evolution over geologic time, noting its detectable biomarkers and the signatures of life found in our atmosphere. This model is the basis of comparison for analyzing light from planets in distant solar systems. By looking for similar spectral characteristics, indicators of atmospheric composition, scientists in the near future may be able to determine if the planet harbors life – and at what stage that life form may be in its evolution. Using such telescopes as Kepler, James Webb Space Telescope (JWST), Darwin and Terrestrial Planet Finder (TPF), and masking the star light, the light from small Earth-like planets can be collected and analyzed. Join us for what promises to be an intriguing talk: How to Spot a Pale Blue Dot in the Night Sky.
Please join us for a pre-meeting dinner discussion at Changsho, 1712 Mass Ave, Cambridge, MA at 6:00pm before the meeting. |
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