by Jamie Carter
Spanish equivalent version
Should we be sending
messages to aliens?
Are we alone? Probably not...
After all, astronomers
have already found 4,001 confirmed exoplanets in our Milky Way
galaxy, and expect there to be over 50 billion
For scientists gathering
in Paris today, the question is different:
why haven't we
made contact (???...)
What is the
Fermi Paradox and the "Great Silence?"
Italian physicist Enrico Fermi asked 'where is everybody?'
back in 1950 in what's now called the
It addresses a
contradiction in astronomy, and can be summarized thus:
life and even intelligent alien civilizations are not just
likely, but highly probable, then why have none of them been in
contact with us?
Are there biological
or sociological explanations for this "Great Silence?"
"We are very
interested in the scientific approach used in the analysis
of the Fermi Paradox and the search for intelligent life in
the universe," said Cyril Birnbaum and Brigitte David at the
Cité des Sciences et de l'Industrie (Cité), the science
museum in Paris that's hosting today's meeting.
'Are we alone?' affects us all, because it is directly
related to humanity and our place in the cosmos."
Illustration of the view from the innermost
of the two exoplanets
orbiting Gliese 667 C (largest star, a red dwarf)
Gliese 667 system, which lies around
24 light years from Earth in the
What are scientists doing in Paris?
Today, leading researchers from the fields of astrophysics, biology,
sociology, psychology, and history are meeting at the Cité.
two years, METI International (METI stands for messaging
extraterrestrial intelligence) organizes a one-day workshop in Paris
as part of a series of workshops entitled 'What is Life? An
Extraterrestrial Perspective'," said Florence Raulin Cerceau,
co-chair of the workshop and a member of METI's Board of Directors.
The scientists are discussing some pretty insane-sounding questions:
Are extraterrestrials staying silent out of concern for how contact
would impact humanity?
Do we live in a "galactic zoo?"
Should we send intentional radio messages to nearby stars to signal
humanity's interest in joining the "galactic club?"
Will extraterrestrial intelligence be similar to human intelligence?
Did life get to earth from elsewhere in the galaxy (interstellar
"This puzzle of why we haven't detected extraterrestrial life has
been discussed often, but in this workshop's unique focus, many of
the talks tackled a controversial explanation first suggested in the
1970s called the 'zoo hypothesis'," said Raulin Cerceau.
Ah yes, the
idea that we're being watched by aliens and ... perhaps even being
protected by them.
If a zebra started pounding out
a series of prime numbers in a zoo,
would we re-evaluate their intelligence?
That's how some scientists
are characterizing the search
for extraterrestrial intelligence.
What is the "zoo hypothesis"?
This is a mind-warping idea that there are alien civilizations out
there (no, not on Oumuamua) that know all about us, but purposefully
hide from us.
It certainly explains the "Great Silence."
extraterrestrials are watching humans on Earth, much like we watch
animals in a zoo," explains Douglas Vakoch, president of METI.
can we get the galactic zookeepers to reveal themselves?"
workshop, Douglas Vakoch proposed that humans should be more active in the
search for extraterrestrial intelligence.
"If we went to a zoo and
suddenly a zebra turned toward us, looked us in the eye, and started
pounding out a series of prime numbers with its hoof, that would
establish a radically different relationship between us and the
zebra, and we would feel compelled to respond," he said.
It's hard to disagree with that.
"We can do the same with
extraterrestrials by transmitting powerful, intentional,
information-rich radio signals to nearby stars," he said.
No, there are no aliens watching us from
interstellar asteroid that passed
through the solar system in late
What is the "galactic quarantine" theory?
Think the "zoo hypothesis" theory is insane?
That's nothing compared
to another theory about alien benevolence.
"It seems likely that
extraterrestrials are imposing a 'galactic quarantine' because they
realize it would be culturally disruptive for us to learn about
them," said Jean-Pierre Rospars, the honorary research director at
the Institut National de la Recherche Agronomique and co-chair of
"Cognitive evolution on Earth shows random features
while also following predictable paths... we can expect the
repeated, independent emergence of intelligent species in the
universe, and we should expect to see more or less similar forms of
intelligence everywhere, under favorable conditions," he added.
"There's no reason to think that humans have reached the highest
cognitive level possible. Higher levels might evolve on Earth in the
future and already be reached elsewhere."
The Robert C. Byrd Green Bank Telescope (GBT)
at the Green Bank
Observatory, West Virginia,
is the world's largest fully steerable
What does the Drake Equation try to do?
A formula to estimate the number of technological civilizations in
the Milky Way galaxy, the Drake Equation is an attempt to put the
Fermi Paradox into numbers.
Drake Equation was posited in 1961
Frank Drake, a radio astronomer at the National Radio
Astronomy Observatory in Green Bank, West Virginia.
What is the Drake Equation?
OK, don't expect any answers here. The formula below, which comes
from the SETI Institute might seem impressive, but it's mostly
Practically speaking, its purpose is not to find a
definitive answer, but to keep the discussion going about the search
for extraterrestrial intelligence.
N = R* x fp x ne x fl x fi x fc x L
N = The number of civilizations in the Milky Way Galaxy whose
electromagnetic emissions are detectable.
R = The rate of formation of stars suitable for the development of
fp = The fraction of those stars with planetary systems.
ne = The number of planets, per solar system, with an environment
suitable for life.
fl = The fraction of suitable planets on which life actually
fi = The fraction of life bearing planets on which intelligent life
fc = The fraction of civilizations that develop a technology that
releases detectable signs of their existence into space.
L = The length of time such civilizations release detectable signals
METI puts a special emphasis on those last three terms, which
explore not just the frequency of intelligence-bearing worlds, but
how long they last (before they get wiped out).
vs. Interstellar Colonization
While for now, radio astronomy is the only practical way of humans
sending messages out into the cosmos, says one scientist, only
full-blown colonization of other stars is the only way to prove the
existence of intelligent life.
"It appears that although radio
communications provide a natural means for searching for
extra-terrestrial intelligence for civilizations younger than a few
millennia, older civilizations should rather develop extensive
programs of interstellar colonization," said Nicolas Prantzos,
director of research of the Centre National de la Recherche
Scientifique (CNRS), in advance of Monday's meeting.
"This is the
only way to achieve undisputable evidence, either for or against the
existence of extraterrestrial intelligence, within their lifetime."
Dr. Frank Drake at the National Radio Astronomy Observatory
in Green Bank, West Virginia used the 25-meter dish
Project Ozma, in which he searched two nearby stars
called Epsilon Eridani
(an artist's impression pictured here)
and Tau Ceti for signs of
Why aliens could be very different from humans
Why should they be even remotely similar?
"The environment on an exoplanet will impose its own rules," said Roland Lehoucq, an
astrophysicist who works at the Commissariat à l'Énergie Atomique (CEA).
"There is no trend in biological evolution: the huge range of
various morphologies observed on Earth renders any exobiological
speculation improbable, at least for macroscopic 'complex' life."
Skeptical that humans would have much in common with
extraterrestrial life forms, Roland Lehocq discussed,
anthropocentrism in our understanding and description of alien life"
and how difficult it is for humans to imagine extraterrestrial
intelligence radically different from ourselves.
We're too self-obsessed to even imagine extraterrestrial
life, let alone find and communicate with it, and if there's not
going to be proof within our lifetimes, we're not much interested in