Pacific Rise. They found natural chimneys
belching black smoke into the ocean, which
they nicknamed black smokers. Known
more formally as hydrothermal vents, these
are places where hot water percolates
through the ocean bedrocks, dissolving
minerals as it goes, and then shoots back up
into the frigid ocean water. The sudden
change in temperature causes the minerals to
precipitate, creating the black ‘smoke’.Astonishingly, the Scripps team found
thriving biological communities fuelled by
the dissolved minerals around the vents.
These were sustained not by energy fromthe Sun, but by the geothermal energy
that heated the water.
The discovery of oceans in some of the
outer moons of the Solar System, such as
Jupiter’s Europa and Saturn’s Enceladus,
instantly raised the possibility of black smokers
on those far-off moons. Perhaps most
intriguingly, some of the microbes found
around the black smokers were shown to be
genetically the most primitive organisms on
the planet, which raised the prospect that these
could be the very places where life began. If
that were true, why not on the ocean f loors in
the outer Solar System as well?
Over the next six pages, we’ll survey the
three moons where life is most likely
to be lurking right now.“If we can find places
where life began
independently from
life on Earth, then...
wow! "
David Rothery, The Open University
In this picture, the moons
Io and Europa hover over
Jupiter’s Great Red Spot