28 | New Scientist | 25 April 2020
Book
Alien Oceans: The search for
life in the depths of space
Kevin Hand
Princeton University PressIN THE late 1970s, two different
voyages of discovery transformed
our ideas about alien life. In 1977,
hydrothermal vents were found,
belching out “smoke” in the
Galapagos rift at the bottom
of the Pacific Ocean. The smoke
was actually a superheated fluid
rich in hydrogen, methane,
hydrogen sulphide and minerals
essential to life.
The chimneys were host to
never-before-seen creatures,
thriving in a place we had
previously thought was
completely and utterly lifeless.
Two years later, in 1979, NASA’s
Voyager spacecraft flew past
Jupiter and gathered the first
evidence that some of the gas
giant’s moons contained oceans.
Kevin Hand is a child of that
historical collision between ocean
and interplanetary discovery.
While his adventures exploring
hydrothermal vents provide him
with a cracking opening chapter
to his new book, Alien Oceans, he
is better known for his later work,
being NASA’s deputy chief scientist
for solar system exploration, where
he has spearheaded an effort to
land a spacecraft on Jupiter’s
moon Europa.
Life on the underside of the ice
on Europa, says Hand, “could be
like an inverted version of life we
see lining the cracks of a sidewalk”.
Wresting secrets from Europa’s
hidden ocean will be a frustrating
business. You can’t peer through
the surface to the sea floor. You
will have to get up close with a
robotic submersible. Then you
will have to contend with the factlittle from, but that turns out to
contain the best real estate for life.
We know that physics and
chemistry will work the same
way, however far we venture.
What we don’t know is whether
biology does the same. “It is the
phenomenon that defines us,”
Hand writes, “and yet we do not
know whether it is a universal
phenomenon.”
Surprisingly many places in our
solar system turn out to be capable
of supporting “our kind of life”:
carbon-based life organised
around RNA or DNA. But whether
we ultimately find life in those
places is quite another question.
After all, a world that is habitable
could have the conditions needed
to support life, but not necessarily
those needed for life to get goingthat no electronic mode of
navigation or communication
will be able to interact with the
outside world through the ice,
so the submersible will need
to be fully autonomous, coming
to the surface periodically to
report back what it finds.
But Hand’s more immediate
problem is logistical. Nothing
is likely to land on Europa
before 2040 because NASA’s
subcontractors can’t find a large
enough skilled workforce to
complete their existing projects.
While he waits, Hand can only
analyse what information is
available, plan future missions
as best he can and speculate
about what we might one day
find in the outer reaches of our
solar system – a zone we expectedViews Culture
Europa could be the best
place to look for alien
life in our solar systemNASA
/JP
L-CAL
TE
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/SETI^ INS
TITUTEIs there life out there?
Extraterrestrial oceans are an obvious place to search for alien life, but getting
there and having a look won’t be easy, finds Simon Ings“ Any life discovered in
Titan’s liquid methane
lakes would have a very
different biochemistry
from ours”