[shank8]

We define the word habitable to be the ability for a planet to have life on it. But that is by standards of Oxygen/Nitrogen breathing, H20 drinking lifeforms. Who's to say that there aren't carbon life forms that have evolved to live off elements that are toxic to us

[mehmehshoe]

We have those life forms here already=) Microbes that eat arsenic. I am sure there are a lot more examples in extreme areas of our planet if there was a bigger budget to find them.

[Goosey]

No one, but finding ETs is only half of the excitement. The other half is interstellar colonization.