life as we know it.
they are excited 'cause it seems suitable for life as we know it.

what would life as we didn't know it look like?

it could be all over...

its just that we don't know it
(don't identify it as such)

(same thing pops up with 'intelligence' and with respect to whether computers might be able to think one day)

life is a bit of a tricky notion too...