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Alex, I think there is sufficient diversity in our own (do we own it?) solar system to advise caution in claiming 'Earth like' planet discoveries. Consider a planet orbiting in the comfort zone of a distant G2V star. It has a mass and orbital period similar to Earth. It has an atmosphere that might be coaxed into supporting living organisms, and spectroscopic studies suggest plentifull water deposits. What I suspect we are a very long way short of is determining that it has a day equal to its year or not, and that its polar axis is within 1 or 2 degrees of pepandicular to the plane of its orbit or not.
I am assuming that it would be feasable for a planetary body of Earth like mass, in the comfort zone to only rotate once a year, and or also have no polar inclination and or have no influential moon.
Such a planet would not be 'Earth like' IMHO and might not be host to any living things.
I guess discovery of a planetary body of Earth like mass in the comfort zone of a G2V star should stop short of being claimed an Earth like planet, but rather be described as a small inner planet that might turn out to be similar to the Earth.
Cheers,
Doug
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