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FROM THE EDITOR
“Life can’t be magicked into existence,”
the great evolutionary biologist Richard
Dawkins has said. And it doesn’t need
to be. When most astronomy enthusiasts think of
life in the cosmos, they immediately dream of aliens
and UFOs. But statistically speaking, one might
expect many worlds filled with microbes, the simplest
forms of life, for every one world that might evolve life
into something more complex, like on Earth.
Spectroscopy tells us that chemistry works the same way
everywhere in the universe. We know from meteorites that
complex organic molecules are abundant in the solar system. And
the particles returned in 2006 by the Stardust spacecraft from Comet
Wild 2 contained glycine — the simplest amino acid and one of the
fundamental building blocks of life.
Experiments going back to the 1950s, when Stanley Miller and
Harold Urey set up their lab equipment, have shown that the primor-
dial soup, along with energy sources on early Earth such as lightning,
could have straightforwardly created complex organics and led to the
development of RNA and DNA. Chemical processing from simple
elements to complex organics seems to have happened quickly on our
planet, soon after the quieting of the Late Heavy Bombardment, when
numerous asteroids, comets, and other bodies were smashing into
Earth and the other inner solar system worlds.
The more we investigate our own planet — under icy crusts, in
searing volcanic calderas, at extremely high altitudes, or on the
seaf loor — the more we see that life is tenacious and able to f lourish
under extreme environments.
Life doesn’t need magic. It simply needs systematic biochemistry.
So the issue may not be, “How could life possibly have started on
Earth?” so much as, “It’s probable that many, many worlds with the
right conditions harbor life.”
Some of these worlds might even exist within our solar system,
away from our blue planet. Could microbes be floating in Titan’s
methane lakes? Hurling skyward in the icy cryovolcanoes of
Enceladus? Could the subsurface aquifers on Mars hold microbial
life-forms, or could they have once evolved there, when the planet
was wetter? Before New Horizons f lew by Pluto, no one would have
guessed that microbes could exist in the icy crust of that distant world,
but now scientists consider it a possibility. And Triton and Europa
could be hosts, too. The Europa Clipper mission is now on the boards
as a first dive into investigating this question.
I hope you enjoy this special issue of the magazine, and that you’ll
ponder not just the fragility of life, but also its tenacity — and the fact
that we might not even be completely alone in our own planetary
system.Yo u r s t r u l y,
David J. EicherNo magic
required
Editor David J. Eicher
Art Director LuAnn Williams Belter
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on a U.S. bank. BN 12271 3209 RT. Not responsible for unsolicited materials.Pluto’s Sputnik
Planitia provides a
tantalizing clue that
the world harbors an
underground ocean —
and thus could be an
abode for life. NASA/
JHUAPL/SWRI
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