Of all the questions that remain unanswered by science, the question about life in the Universe is the one that captures our interest the most. In exploring alien civilization, NASA established the Search for Extraterrestrial Intelligence (SETI) program to discover signs of intelligent life outside the Earth.
In a recent study, experts from the SETI Institute, Berkeley SETI Research Center, and the University of Washington reported an exciting development in identifying signals from advanced civilizations. Using data from the Transiting Exoplanet Survey Satellite (TESS) mission, they monitor the SETI ellipsoid to look for alien technosignatures. The result of their study is discussed in the paper "Searching the SN 1987A SETI Ellipsoid with TESS."
What are Technosignatures?
In our efforts to look for signs of alien civilization, scientists acknowledge that the first confirmed proof of life outside the Earth might not involve biological evidence. Scientists might intercept communication signals through electromagnetic waves, such as radio, or even find telescopic evidence of engineering skills.
Most investigations focus on non-technological life, but NASA scientists have also begun considering what technosignatures might look like. Technosignatures refer to potentially detectable signatures and signals that indicate the presence of advanced extraterrestrial civilizations. They are a subset of the larger and far more mature search for biosignatures, or the evidence of microbial or other forms of life that might exist on some known exoplanets.
Quest for Alien Life
The SETI Ellipsoid is a novel technique developed by experts for selecting potential technosignature candidates. It is based on the assumption that distant civilizations, upon witnessing significant cosmic events like supernova 1987A, could use these occurrences as a focal point in emitting synchronized signals to announce their presence in the Universe.
This method can potentially leverage continuous, wide-field sky events and improve our ability to detect potential alien signals. Using this capability, the researchers compensate for the uncertainties in the estimated time-of-arrival of such signals, allowing them to implement the SETI Ellipsoid technique innovatively.
According to lead author Bárbara Cabrales, new surveys of the space offer groundbreaking opportunities to look for technosignatures coordinated with supernovae. Since the typical timing uncertainties are a few months, the team wanted to cover their bases by finding well-documented targets over about one year. Moreover, they recognize the need to conduct as many observations as possible to determine what looks like normal behavior in each target of interest and what might look like a potential technosignature.
The TESS continuous viewing zone covers 5% of all TESS data from the first three years of its mission. The scientists used the advanced 3D location data from Gaia Early Data Release 3 to examine these data. This helped them identify 32 prime targets within the SETI Ellipsoid in the southern TESS continuous viewing zone, with uncertainties refined to better than 0.5 light years.
Although no anomalies were revealed by the initial examination of TESS light curves during the Ellipsoid crossing event, the groundwork laid by this study paves the way for expanding the search to other surveys. Applying the SETI Ellipsoid technique to examine large archival databases is a monumental step forward in the search for technosignatures.
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