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In recent years, the focus of SETI
has moved away from merely
listening for messages. Efforts have
been directed toward picking
up biochemical signs of life or
indications of advanced technology.
Alien life should leave its signature
in evolved planetary atmospheres,
volatile molecules, or complex
organic chemicals that could only
be created by life processes. Highly
technological societies may have
learned how to harvest the energy
of their star. A “Dyson sphere”
megastructure completely or
partially surrounding a star to
capture its energy would affect the
star’s observed output. It may also
be possible to observe signs of
asteroid mining or directly detect
extraterrestrial spacecraft.
A cautious approach
In 2015, the Breakthrough
Initiatives program was
launched with the backing of
Russian billionaire Yuri Milner.
In addition to a $1,000,000 prize
pool for SETI research and a plan
to send a fleet of spacecraft to a
nearby star, an open competition
was announced to design a
digital message to be sent to an
extraterrestrial civilization. The
Breakthrough Message project
aims to accurately and artistically
represent humanity and Earth,
but pledges not to transmit any
message until the risks and
reward of contacting advanced
civilizations have been debated.Looking at ourselves
In 1990, Carl Sagan persuaded
Voyager 1’s controllers to swivel
its camera back toward Earth.
From 4 billion miles (6 billion
kilometers) away, the craft captured
the “Pale Blue Dot” image. Sagan
wrote: “Everyone you love, everyone
you know, everyone you ever heard
of, every human being who ever
was, lived out their lives on a mote
of dust suspended in a sunbeam.”
Sagan stressed the importance ofNEW WINDOWS ON THE UNIVERSE
looking at ourselves: “The Earth
is the only world known so far to
harbor life. There is nowhere else,
at least in the near future, to which
our species could migrate. Visit,
yes. Settle, not yet. Like it or not,
for the moment the Earth is where
we make our stand.”
SETI represents a series
of questions whose answering
would tell us about Earth’s place
in the universe: whether the
Copernican principle is correct,
and if so, where else life has
evolved. The answers could
eventually provide humans with
a way to transcend their origins
and become a galactic species. ■Voyager 1 sent back this image of
Earth from beyond the orbit of Pluto.
The “pale blue dot” appears in a band
of scattered sunlight.
We are almost certainly
not the first intelligent species
to undertake the search ...
Their perseverance will be
our greatest asset in our
beginning listening phase.
Project Cyclops Report,
NASA