by Jane Icke
University
of Nottingham
June 15, 2020
from
Eurekalert Website
Credit: CC0 Public Domain
One of the biggest and longest-standing questions in the history of
human thought is whether there are other intelligent life forms
within our Universe.
Obtaining good estimates
of the number of possible extraterrestrial civilizations has however
been very challenging.
A new study (The
Astrobiological Copernican Weak and Strong Limits for Intelligent
Life) led by the University of Nottingham and published
today in The Astrophysical Journal has taken a new approach
to this problem.
Using the assumption that
intelligent life forms on other planets in a similar way as it does
on Earth, researchers have obtained an estimate for the number of
intelligent communicating civilizations within our own galaxy - the
Milky Way.
They calculate that there
could be over 30 active communicating intelligent civilizations
in our home Galaxy.
Professor of Astrophysics at the University of Nottingham,
Christopher Conselice who led the research, explains:
"There should be at
least a few dozen active civilizations in our Galaxy under the
assumption that it takes 5 billion years for intelligent life to
form on other planets, as on Earth."
Conselice also explains
that,
"The idea is looking
at evolution, but on a cosmic scale. We call this calculation
the Astrobiological Copernican Limit."
First author Tom
Westby explains:
"The classic method
for estimating the number of intelligent civilizations relies on
making guesses of values relating to life, whereby opinions
about such matters vary quite substantially.
Our new study
simplifies these assumptions using new data, giving us a solid
estimate of the number of civilizations in our Galaxy.
The two Astrobiological Copernican limits are that
intelligent life forms in less than 5 billion years, or after
about 5 billion years - similar to on Earth where a
communicating civilization formed after 4.5 billion years.
In the strong
criteria, whereby a metal content equal to that of the Sun is
needed (the Sun is relatively speaking quite metal rich), we
calculate that there should be around
36 active civilizations in our Galaxy."
The research shows that
the number of civilizations depends strongly on how long they are
actively sending out signals of their existence into space, such as
radio transmissions from satellites, television, etc.
If other technological
civilizations last as long as ours which is currently 100 years old,
then there will be about 36 ongoing intelligent technical
civilizations throughout our Galaxy.
However, the average distance to these civilizations would be 17,000
light-years away, making detection and communication very difficult
with our present technology.
It is also possible that
we are the 'only' civilization (sic) within our Galaxy unless
the survival times of civilizations like our own are long.
Professor Conselice continues:
"Our new research
suggests that searches for
extraterrestrial intelligent civilizations
not only reveals the existence of how life forms, but also gives
us clues for how long our own civilization will last.
If we find that
intelligent life is common then this would reveal that our
civilization could exist for much longer than a few hundred
years, alternatively if we find that there are no active
civilizations in our Galaxy it is a bad sign for our own
long-term existence.
By searching for
extraterrestrial intelligent life - even if we find nothing - we
are discovering our own future and fate."
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