If life is common in our Universe, and we have every reason to suspect it is, why do we not see evidence of it everywhere? This is the essence of the Fermi Paradox, a question that has plagued astronomers and cosmologists almost since the birth of modern astronomy.
It is also the reasoning behind the Hart-Tipler Conjecture,
one of the many (many!) proposed resolutions, which asserts that if advanced
life had emerged in our galaxy sometime in the past, we would see signs of
their activity everywhere we looked. Possible indications include
self-replicating probes, megastructures, and other Type III-like activity.
On the other hand, several proposed resolutions challenge
the notion that advanced life would operate on such massive scales. Others
suggest that advanced extraterrestrial civilizations would be engaged in
activities and locales that would make them less noticeable.
In a recent study, a German-Georgian team of researchers
proposed that advanced extraterrestrial civilizations (ETCs) could use black
holes as quantum computers.
This makes sense from a computing standpoint and offers an
explanation for the apparent lack of activity we see when we look at the
cosmos.
The research was conducted by Gia Dvali, a theoretical
physicist with the Max Planck Institute for Physics and the physics chair at
Ludwig-Maximilians-University in Munich, and Zaza Osmanov, a professor of
physics at the Free University of Tbilisi, and a researcher with the Kharadze
Georgian National Astrophysical Observatory and the SETI Institute.
The paper that describes their findings recently appeared online
and is being reviewed for publication in the International Journal ofAstrobiology.
The first SETI survey (Project Ozma) was conducted in 1960
and was led by famed astrophysicist Dr. Frank Drake (who proposed the Drake
Equation). This survey relied on the Green Bank Observatory's 26-meter
(85-foot) radio telescope to listen for radio transmissions from the nearby star
systems of Tau Ceti and Epsilon Eridani.
Since then, the vast majority of SETI projects have been
geared towards the search for radio technosignatures, owing to the ability of
radio waves to propagate through interstellar space. As Dvali and Osmanov explained
to Universe Today via email:
"Currently, we are mainly looking for radio messages,
and there have been several attempts to study the sky for finding the so-called
Dyson sphere candidates – megastructures built around stars. On the other hand,
the problem of SETI is so complex that one should test all possible channels.
"A whole "spectrum" of technosignatures might
be much wider: for instance, the infrared or optical emission from
megastructures also built around pulsars, white dwarfs, and black holes. A
completely new "direction" must be the search for an anomalous
spectral variability of these technosignatures, which might distinguish them
from normal astrophysical objects."
For many researchers, this limited focus is one of the main
reasons SETI has failed to find any evidence of technosignatures. In recent
years, astronomers and astrophysicists have recommended extending the search by
looking for other technosignatures and methods – such as Messaging
Extraterrestrial Intelligence (METI).
These include directed energy (lasers), neutrino emissions,
quantum communications, and gravitational waves, many of which are spelled out
in the NASA Technosignature Report (released in 2018) and at the TechnoClimes
2020 workshop.
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