There are many questions of key interest to SETI (the Search for
Extraterrestrial Intelligence). For example: Why didn't the dinosaurs go to the
moon? They had 200 million years and many species had hands with an opposable
digit, big brains, and were bipedal.
Another entirely different SETI question could be: What do Medieval
Arabic texts have to say about the origin of optics? Light was thought to come
from the eye at the beginning of the Middle Ages but within a few centuries
advanced optical studies emerged from Arab countries with refracting lenses,
prisms, and light was understood clearly to go into, not out of, the eye. Such
an emergent process would be essential to understand if one wants to generalize
the development of telescopes
by intelligent civilizations.
Another interesting SETI-related question: When considering
the communication systems of more advanced
technical civilizations, what can we expect their communication system to
be like? Since something like 98% of the stars in the solar neighborhood are
apparently older than the Sun (and other reasons) we can likely expect that an
extraterrestrial technology will be significantly more advanced than ours. As
an example, one can hardly ignore recent developments in quantum teleportation
as a possible neat trick for instantaneously getting large amounts of information
across the galaxy. (It may or may not be possible to then read that
information faster than light, but that's another story).
These are all interesting SETI questions and might make good
articles themselves. But for today's essay let's ask ourselves this
SETI-related question: Would the development of our technical civilization have
been possible without sponges? (We shall not so much answer this question in
our essay as explain why we asked it.)
Given that a tool-wielding species has to start somewhere,
humans apparently started at least 4 million years ago chipping rocks to form
cutting surfaces. We see wild chimpanzees also doing this today; they also
train their offspring to do this as well so it is a learned, or cultural,
behavior. But as it turns out, banging special kinds of rocks together can
produce an additional feature of technology, one that would come to distinguish
us as a species about 2 million years ago. It all started when we banged
together iron pyrite with ocean sponges - actually, to state it more properly,
we started to bang together iron pyrite with a metamorphosed mixture of chalk
with the internal skeletons of ocean sponges. This metamorphic chalk and sponge
skeletal material is commonly known as "flint." And, as we know, when struck
with iron, it makes a spark of fire. And we are the only species that uses
fire. (I'm not counting an entertaining raven that actually does a nightclub
trick in Las Vegas that includes striking a match to light a cigar.)
So, although flint is an inorganic mineral, almost all the
silicate in it is derived from the dissolved skeletons of sponges. This
strike-sparking is considered the earliest form of fire making. Later steel
would be substituted for the iron pyrite, but flint was used for millennia
before the invention of matches in the 19th century. And it would be difficult
to argue for a more important invention to the survival
of the human species than the making of fire - especially during the
frequent ice ages that accompanied early northward migrations out of Africa. It
could also be argued that fire making was the first big step of our species
toward a technical civilization.
It turns out, then, that the process of sponge skeletons
dissolving in pre-lithified chalk ooze - dehydrated and hardened into
microscopic quartz crystals forming flint - was essential (along with trees,
but that's another story) to the survival and eventual technical success of our
species on this planet. It could be argued that without sponges humans would
not be listening to and transmitting messages over interstellar distances
today. So, looking
for extraterrestrial technology? Then it might be a good idea to know where
in the galaxy the sponges are. The humble sponge, or something like it, may be
essential for any species to first come up with the making of fire. And on our
planet, if you don't have a dishwasher, they still come in pretty handy too.
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