Should we only look for life on 'Earth-like' exoplanets?

[LongTomH]

Huffington Post has an interesting interview with MIT astronomer Sara Seager: 'Alien Earths' May Not Be Only Exoplanets Capable of Supporting Life, Astronomer Says.

"The number of planets that we're going to be able to see in our lifetime — and look at their atmospheres for signs of life— is so small that we're forced to be open-minded," Seager told SPACE.com.

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"If there is one important lesson from exoplanets, it is that anything is possible within the laws of physics and chemistry," Seager writes in the Science article. "Planets of almost all masses, sizes and orbits have been detected, illustrating not only the stochastic nature of planet formation but also a subsequent migration through the planetary disk from the planet’s place of origin."

The James Webb Space Telescop (JWST), scheduled for launch in 2018, may be able to do spectroscopic surveys of exoplanets relatively close to Earth: "A few tens of light-years" away.

Seager said she hopes her review article in Science helps her fellow astronomers make the most of this small pool of observable candidates.

"I hope it gets people to realize that so many types of worlds could be habitable, and that our chance of finding one is higher when we accept that," she told SPACE.com.

Edited to add: The article does have an interesting discussion of factors that can make a 'non-Earthlike' planet more hospitable to life, such as a greenhouse effect that could make a planet outside the usually accepted 'habitable zone' of a star warm enough for liquid water.