QUESTION:
Why do we, as humans, think it's necessary to find water as a key element to
support other forms of life? The universe as we know it is so vastly
infinite that we appear as a tiny microscopic speck of dust; and I find it
hard to believe we can be so naive as to assume that all other life forms
need water to survive or be created like us. Am I off base in this thought?
All I keep hearing is how the scientists hope they find some evidence of
water to help support the theory of past life on Mars.

ANSWER from Bruce Jakosky on July 16, 1997:
Water isn't magical in its qualities, but it is abundant.  The qualities
that water has that make it useful for life are (i) that it can be present
as a liquid (this is the most important), (ii) that lots of things can
dissolve in it (so that nutrients can be brought in, and waste products can
be removed).  Other liquids could do this; for example, there might be
liquid ethane/methane lakes or oceans on Titan.  However, water is one of
the most abundant species in the universe.

In other words, it is conceivable that other liquids could be suitable for
life, but by focussing on water we are not losing much.  In our own solar
system, liquid water was, is, or may be present on Mars, Europa, possibly
early Venus, and possibly early Titan.  All other possible liquids may be
present only on Titan.