Image: The SETI Institute's Allen Telescope Array in California seeks out radio transmissions from hypothetical aliens. Is there another way? Credit: Colby Gutierrez-Kraybill/Wikimedia Commons In one of Carl Sagan's last books, he noted that astronomy has brought humanity to a series of "great demotions." Simply put: When we first observed the night sky, we thought the Earth was in the center of the universe. Over time, as he described in Pale Blue Dot, we tried out other theories as the criteria fit: Maybe the sun is at the center of the universe? Perhaps we're in an important part of the galaxy?

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We now know the Earth is in the suburbs of the Milky Way, and our solar system is only special because we live in it, but this series of demotions shows us one thing: it's easy to project our image on to the universe. This is especially true when searching for life. Because there is only one case of life as we know it -- life on Earth -- it's easiest to look for life like ours. But in reality our kind of life may not be the most common type to look for after all.

A new paper in Astrobiology is asking the astronomy community to help the SETI Institute. (SETI stands for "Search for Extraterrestrial Intelligence.") With more data on exoplanets coming in from the Kepler space telescope, and 50 years of space and SETI observations behind us, the hope is new tools can emerge to improve the search for life.

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"A key concept is the one of co-evolution of life and environment ... Each planet is a unique planetary experiment, and if we are starting to model these environments, then we can start to figure out what kind of diversity is out there," author Nathalie Cabrol, the SETI Institute's senior research scientist and director of the Carl Sagan Center, told Discovery News.

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