We've been searching for signs of
extraterrestrial life for the past
50-plus years and so far we have found
no evidence of anything beyond our
planet. But what are we searching for we
are framed by our own human expectations,
our current technology and understanding
of the universe and the physics that we
believe make it work. In other words we
are looking for what we might expect
other beings like ours might send using
technology that we know about. The first
problem is that if we got a signal or a
message from ET could we understand it.
Would it be a signal broadcast and
intended for other civilizations like us
that might contain clues to help
decipher it or would it be just a
byproduct of something they are doing
going about their everyday existence.
Take our output into the cosmos for
example. For the past 100 years or so we
have been accidentally transmitting
radio waves into space from the most
basic spark transmissions of Marconi's
first tests to high-speed data
communications with satellites today and
everything else in between. Nearly all of
this information has been intended for
us other than the intentional signals
which we have sent out and not for
extraterrestrial beings. For any ETS
discovering our transmissions, assuming
that they are nearby enough not to be hearing those
first spark tests of Marconi, it would be
a bit like us stumbling across ancient
writings in an unknown language and
trying to figure out what the message is
saying. In fact there are still a handful
of ancient writing systems here on earth
like the "Linear A" that we still can't
decipher and they were written by modern
humans just a few thousand years ago. Any
message from ET will be coming from a
civilization which had evolved in a
radically different way from us. Another
example we might find on earth is that a
dolphin's, whale's and elephant
communications. We know we're
intelligence and that they communicate
using some form of language but we have
little to no idea of what they are
saying to each other. Theorists believe
that whilst decoding any message from ET
may
extremely difficult by looking at the
way the message was sent could lead to
clues on how to decipher it. The very
fact that it is being received via radio
transmission and that would have been
encoded with some sort of signal in some
way mean ET may not be that different
from us in it they understand about
space, the universe, how to send signals
and that they must also then know about
maths and so on so forth. This could lead
to possible extraterrestrial rosetta
stones that could unlock further meaning
in the message. The second problem is
that the distance between us and any
potentially advanced species is huge we
also have to be looking in the right
place at the right time. If a signal only
lasts for a few seconds or minutes and
our receivers are looking in a different
direction we'll miss it completely or it
might be so weak because of the distance
but we might not detect it in the first
place. If we were very lucky we might
receive a signal that is less than a
hundred light-years away but it is far
more likely to come from thousands or
tens of thousands of light-years away
because that's where most of the stars
and potential life-supporting planets
are in our galaxy. This effectively rules
out any realistic chance of
communication, assuming we got lucky then
we received a signal today from a local
source approximately a hundred
light-years away. If we sent a reply
within a few months after figuring out
whether or not to respond, it would be
another hundred years before they got
our reply, a 200 year round trip that's
even if they are still listening or even
able to listen and this brings us to the
third problem in that it will be highly
unlikely that we will be at the same
stage with technological development as
ET, the earlier distance problem also
compounds this. If we received a radio
signal from a source 10,000 light-years
away that would have been sent whilst
our ancestors were still living in caves
and ET may have been then as
technologically advanced as we are now.
It's hard to imagine where we might be
in ten thousand years time at our
rate of development but a chances are
but we have discovered a radically
different way of communicating across
the vast distances of space. The
extraterrestrials that sent the message
10,000 years ago may now be using
technologies which are way in advance of
our understanding or ability to pick up
and that's why it might be so quiet out
there. We might be doing with radio what
is the technological equivalent of
trying to pick up an email with a couple
of cans and a piece of string. We are
listening for ET using a basic method of
modulated radio waves which will be far
too slow for any advanced spacefaring
species to use. I can't say what methods
they might use, it maybe interdimensional
or quantum entanglement we won't know
until it's discovered but whatever it is
it will have to be faster than light to
make it useful over the vast distances
between star systems which also puts it
out of the realm of our current
understanding of physics. So whilst we
have nothing better than radio I
personally don't think that we will find
any signals from ET, even though I do think
there are many advanced civilizations
out there amongst the stars in our own
galaxy. If we do find anything with radio
it will probably be from ET's that are
too far away for any communication with
and probably in the same situation as us,
isolated pockets of intelligence that
haven't yet figured out how to get for
one star to another within the lifetime
of a crew. Everything else will be way
way ahead of us and may not really be
interested in communicating with a
species until we can communicate with
them at their level just as we don't go
backwards when we discover a Lost Tribe.
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