2018-06-12 02:52:57 UTC
Arthur Clarke wrote "Earthlight" in 1955. Humans have become
a multiplanetary species, but that also causes a problem!
Does this explanation of our important heavy metals currently
"The human race had been born on a world unique in the solar system,
loaded with a mineral wealth unmatched elsewhere. This accident of fate
had given a flying start to man's technology but when he reached the
other planets he found his surprise and disappointment that for many of
his most vital needs he must still depend on the Home world.
Earth is a densest of all the planets, only Venus approaching it in this
respect. But Venus has no satellite and the earth-moon system forms a
double world of a type found nowhere else among the planets. It's mode
of formation is a mystery still but it is known that when the Earth was
Molten the moon circled at only a fraction of its present distance and
raised gigantic tides in the plastic substance of its companion.
As a result of these internal tides the crust of the earth is rich in
heavy metals - far richer than that of any other of the planets: they
hoard their wealth far down within their unreachable cores, protected by
pressures and temperatures that guard them from man's depredations. So
as human civilization spread outward from Earth the drain on the mother
world dwindling resources steadily increased.
The Light Elements existed on the other planets in unlimited amounts but
such essential Metals as mercury, lead, uranium, Platinum, thorium and
tungsten were almost unobtainable. For many of them no substitutes
existed: their large-scale synthesis was Impractical despite two
centuries of effort and modern technology could not survive without them.
It was an unfortunate situation and a very galling one for the
independent republics of Mars, Venus, and larger satellites which had
now united to form the Federation. --"