It is intriguing to consider the consequence that shaking hands with an alien could have, whether this was from a literal, E.T.-esque encounter, or perhaps more plausibly, from a metaphorical ‘handshake’, for
example if we discovered alien microbes on mars and studied them in the
laboritory back on earth. It is even more intriguing to imagine what
such encounters could teach us about the fundamental principles of life.
However could they also pose a risk to life on earth? I am not
referring to a War of the Worlds
style alien invasion, but for example could an extra terrestrial virus,
inadvertently released, go on to parasitize our cells? Could such a
life form even swap genes with our planet’s organisms, dramatically
altering the course of evolution on earth? These
possibilities may be rather far fetched, but perhaps they are not entirely
implausible.
The
earth is home to an incredible diversity of life, perhaps 100 million
species, broadly divisible into three domains; the Eukaryotes
(everything from amoeba to blue whales), Bacteria, and Archaea
(superficially similar to Bacteria but perhaps evolutionarily closer to
Eukaryotes). In a sense, however, the earth only possesses one form of
life. That is, all species seem to descend from a single common
ancestor, and all share the same basic molecular machinery.