Is That Really Alien Life?

Is That Really Alien Life?
An artist's concept of a planetary lineup, featuring five exoplanets that may be similar to Earth: (L to R) Kepler-22b, Kepler-69c, Kepler-452b, Kepler-62f and Kepler-186f, with Earth on the far right. With more advanced telescopes, scientists may be able to find signs of life on exoplanets like these.

By Calla Cofield
Space.com
8-3-15

      The search for life elsewhere in the universe is on the cusp of a new era: When scientists will have the opportunity to study the atmospheres of potentially habitable planets with future, technologically advanced telescopes. Humans have no foreseeable way to travel to these worlds to study them up close, but the chemical mixtures that surround them may reveal the presence of life.

There is no single "smoking gun" for life; no atmospheric mixture that can definitively declare, "Something lives here!" (At least, not that scientists know of). And searching for life from afar carries a heavy burden of proof: Any signal that looks like life could actually be created in some clever, non-biological process that scientists haven't yet thought of.

So, in addition to coming up with ideas for what life might look like on alien planets, scientists must also come up with ways that non-living processes could create those same signatures. Scientists are now working hard to think up new examples of these "false positives," in an effort to avoid a misstep when the data start to appear. . . .
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