living systems—which, of course, simply pushes the origin question
off to another place and time.
Nonetheless, many scientists believe it is only a matter of time
before a plausible scenario for the origin of life is constructed. Given
that our science of biochemistry and molecular biology is less than
a hundred years old, the pace of progress in what we consider to be
deep understanding of life is truly sensational. So, is this it? Are we on
the verge of some kind of complete understanding of life and how it
originated from, and is related to, inanimate matter? Many scientists
would say yes. Maybe it is so. Or maybe not.
Now, consider this: as methods of astronomical measurement become
ever more sophisticated, it has been discovered that many stars
appear to have planetary systems, and many of these systems have
planets within a habitable zone. Thus, the likelihood of there being
many Earth-like planets out there in our galaxy, in our universe,
appears to be substantial. It is believed that there are around two hun-
dred billion stars in our galaxy, and something like 1022 (a hundred
billion hundred billion) stars in the observable universe. Thus, there
will be billions of planets on which life might have developed and
evolved. And given the billions of years of time available, the likeli-
hood of sophisticated life forms appearing elsewhere would seem to
be substantial.
Given the youth of our own human species and civilization, it is
often assumed that many life forms out there in the cosmos must be
way ahead of us in technology and other forms of development. So
the question is, where are they? The SETI—Search for Extraterrestrial
Intelligence—program has been going strong for several decades,
searching the heavens for any sign of a radio signal in the cosmic
noise. Why haven't we noticed these alien civilizations, an abundance