A zoom into the Hubble Space Telescope photograph of an enormous, balloon-like bubble being blown into space by a super-hot, massive star. Astronomers trained the iconic telescope on this colorful feature, called the Bubble Nebula, or NGC 7635.
Credits: NASA, ESA, and the Hubble Heritage Team (STScI/AURA), F. Summers, G. Bacon, Z. Levay, and L. Frattare (Viz 3D Team, STScI)
Since the beginning of civilization, humanity has wondered whether we are alone in the universe. As NASA has explored our solar system and beyond, it has developed increasingly sophisticated tools to address this fundamental question. Within our solar system, NASA’s missions have searched for signs of both ancient and current life, especially on Mars and soon, Jupiter’s moon Europa. Beyond our solar system, missions, such as Kepler and TESS, are revealing thousands of planets orbiting other stars.
The explosion of knowledge of planets orbiting other stars, called
exoplanets, and the results of decades of research on signatures of life
- what scientists call biosignatures - have encouraged NASA to address,
in a scientifically rigorous way, whether humanity is alone. Beyond
searching for evidence of just microbial life, NASA now is exploring
ways to search for life advanced enough to create technology.
Technosignatures are signs or signals, which if observed, would allow
us to infer the existence of technological life elsewhere in the
universe. The best known technosignature are radio signals, but there
are many others that have not been explored fully.
In April 2018, new interest arose in Congress for NASA to begin
supporting the scientific search for technosignatures as part of the
agency’s search for life. As part of that effort, the agency is hosting
the NASA Technosignatures Workshop
in Houston on Sept. 26-28, 2018, with the purpose of assessing the
current state of the field, the most promising avenues of research in
technosignatures and where investments could be made to advance the
science. A major goal is to identify how NASA could best support this
endeavor through partnerships with private and philanthropic
organizations.
To view the workshop online, visit: http://www.ustream.tv/channel/asteroid-initiative-idea-synthesis---3
On Thursday, Sept. 27 at 1 p.m. EDT, several of the workshop’s speakers will be answering questions in a Reddit AMA.
What are Technosignatures?
The term technosignatures has a broader meaning than the historically
used “search for extraterrestrial intelligence,” or SETI, which has
generally been limited to communication signals. Technosignatures like
radio or laser emissions, signs of massive structures or an atmosphere
full of pollutants could imply intelligence.
In recent decades, the private and philanthropic sectors have carried
out this research. They have used such methods as searching for
patterns in low-band radio frequencies using radio telescopes. Indeed,
humanity's own radio and television broadcasts have been drifting into
space for a number of years.
NASA’s SETI program was ended in 1993 after
Congress, operating under a budget deficit and decreased political
support, cancelled funding for a high-resolution microwave survey of the
skies. Since then, NASA’s efforts have been directed towards furthering
our fundamental understanding of life itself, its origins and the
habitability of other bodies in our solar system and galaxy.
History of the Search for Technological Life
Efforts to detect technologically advanced life predates the space
age as early 20th century radio pioneers first foresaw the possibility
of interplanetary communication. Theoretical work postulating the
possibility of carrying signals on radio and microwave bands across vast
distances in the galaxy with little interference led to first
“listening” experiments in the 1960s.
Thanks to NASA’s Kepler mission’s discovery of thousands of planets
beyond our solar system,including some with key similarities to Earth,
it’s now possible to not just imagine the science fiction of finding
life on other worlds, but to one day scientifically prove life exists
beyond our solar system.
As NASA's 2015 Astrobiology Strategy
states: "Complex life may evolve into cognitive systems that can employ
technology in ways that may be observable. Nobody knows the
probability, but we know that it is not zero.” As we consider the
environments of other planets, “technosignatures” could be included in
the possible interpretations of data we get from other worlds.
Debate about the probability of finding signals of advanced life
varies widely. In 1961, astronomer Frank Drake created a formula
estimating the number of potential intelligent civilizations in the
galaxy, called the Drake equation, and calculated an answer of 10,000.
Most of the variables in the equation continue to be rough estimates,
subject to uncertainties. Another famous speculation on the subject
called the Fermi paradox, posited by Italian physicist Enrico Fermi,
asserted that if another intelligent life form was indeed out there, we
would have met it by now.
NASA’s SETI work began with a 1971 proposal by biomedical researcher
John Billingham at NASA’s Ames Research Center for a 1,000-dish array of
100-meter telescopes that could pick up television and radio signals
from other stars. “Project Cyclops” was not funded, but in 1976, Ames
established a SETI branch to continue research in this area. NASA’s Jet
Propulsion Laboratory (JPL) also began SETI work.
In 1988, NASA Headquarters in Washington formally endorsed the SETI
program leading to development of the High Resolution Microwave Survey.
Announced on Columbus Day in 1992 - 500 years after Columbus landed in
North America - this 10-year, $100 million project included a targeted
search of stars led by Ames using the 300-meter radio telescope in
Arecibo, Puerto Rico, and an all-sky survey led by JPL using its Deep
Space Network dish. The program lasted only a year before political
opposition eliminated the project and effectively ended NASA’s research
efforts in SETI.
Why Start Looking at Technosignatures Now?
Fueled by the discovery that our galaxy is teeming with planets,
interest in detecting signs of technologically-advanced life is again
bubbling up. Kepler’s discovery in 2015 of irregular fluctuations in
brightness in what came to be known as Tabby’s Star led to speculation
of an alien megastructure, though scientists have since concluded
that a dust cloud is the likely cause. However, Tabby’s Star has
demonstrated the potential usefulness of looking for anomalies in data
collected from space, as signs of technologically-advanced life may
appear as aberrations from the norm.
Scientists caution that we will need more than an unexplained signal
to definitively prove the existence of technological life. For example,
there can be a lot of radio frequency interference from Earth-based
sources.
NASA will continue assessing promising current efforts of research in
technosignatures and investigating where investments could be made to
advance the science. Although we have yet to find signs of
extraterrestrial life, NASA is amplifying exploring the solar system and
beyond to help humanity answer whether we are alone in the universe.
From studying water on Mars, probing promising “oceans worlds” such
as Europa or Saturn’s moon Enceladus, to looking for biosignatures in
the atmospheres of exoplanets, NASA’s science missions are working
together with a goal to find unmistakable signs of life beyond Earth.
And perhaps that life could indeed be more technologically advanced than
our own.
Fascinating.
Editor: Tricia Talbert
Source: NASA/Solar System and Beyond
