"For the first time in human history," said Lisa Kaltenegger, an astronomer at Cornell University, in a talk she gave recently at NASA, "we have the technology to find and characterize other worlds. And there's a lot to learn." The technology she's referring to is TESS, the (Transiting Exoplanet Survey Satellite) set to launch in 2017, and The James Webb Space Telescope, set to launch in 2018. TESS, will use its cameras and sensors to scan the sky for distant planets that might be earth-like. Then The James Webb will allow for close examination and a search for life on the most likely candidates.
Beginning the in the 1990's, a number of massive Jupiter-sized planets have been found orbiting distant stars. Most of these were discovered using the Hubble Space Telescope, but finding much smaller, Earth-sized planets will require a much more powerful instrument. Enter The James Webb. Its 6.5-meter mirror, almost three times the size of Hubble's, will give scientists the resolution required not just to observe these earth-like planets, but to analyze them for signs of life. How will scientists be able to detect life on planets that are so far away? They will use a technique developed by Carl Sagan.
When the Galileo spacecraft did a flyby of Earth in 1990, it recorded the spectrum of light filtered through the Earth's atmosphere. In a 1993 article in the journal Nature, Sagan described how he analyzed Galileo's spectrum data and found in it the signatures of large amounts of oxygen and methane, two gasses given off in huge amounts by life, as we know it. Kaltenegger plans to apply Sagan's technique to data about distant Earth-like planets she collects using the James Webb. "The spectrum of a planet is like a chemical fingerprint," says Kaltenegger, and there's a very good chance that wherever she and her team find atmospheric signatures of large amounts of oxygen and methane, they will be finding the fingerprints of extraterrestrial life.
This careful analysis from afar will take more than just astronomers. To this end, Kaltenegger has founded The Institute for Pale Blue Dots. "The crux of the institute," she says, "is the characterization of rocky, Earth-like planets in the habitable zone of nearby stars. It's a very interdisciplinary effort with people from astronomy, geology, atmospheric modeling, and hopefully biology."
Over the course of the next decade Kaltenegger and her team will likely have even more tools to work with. Two very powerful Earth based telescopes: the Giant Magellan Telescope, scheduled to be completed in 2020, and the European Extremely Large Telescope slated for a 2024 completion, along with a planned planet hunting probe called the Planetary Transits and Oscillations of stars or PLATO, set to launch some time between 2022 and 2024 may all be available to help in the Institute's efforts, as they search for new earths, and hopefully new life, from many light years away.
By Andrew J. Dunlop