SETI Institute uses new ellipsoid technique to search for signals from distant civilizations

A team of researchers from the SETI Institute, the Berkeley SETI Research Center and the University of Washington have reported an exciting development in the field of astrophysics and the search for extraterrestrial intelligence (SETI), using observations from the Transiting Exoplanet Survey Satellite (TESS) mission to monitor the SETI ellipsoid, a method of identifying potential signals from advanced civilizations in the cosmos.

The SETI ellipsoid is a strategic approach to screening potential technosignature candidates, based on the hypothesis that extraterrestrial civilizations, after observing significant galactic events such as supernova 1987A, could use these events as a focal point to emit synchronized signals to announce their presence.

In this work, researchers show that the SETI Ellipsoid method can take advantage of continuous, wide-field sky surveys, significantly improving our ability to detect these potential signals. By compensating for uncertainties in the estimated arrival time of these signals using observations spanning up to a year, the team is implementing the SETI Ellipsoid strategy in an innovative way by using cutting-edge technology.

“New studies of the sky offer revolutionary opportunities to search for coordinated technosignatures with supernovae.” said co-author Bárbara Cabrales.

“Typical temporal uncertainties are a few months, so we want to cover our bases by finding well-documented targets over a period of about a year. On top of that, it’s important to have as many observations as possible for each target of interest so we can determine what looks like normal behavior and what might look like a potential technosignature.

Examining data from the TESS Continuous Viewing Area, covering 5% of all TESS data from the first three years of its mission, researchers used advanced 3D location data from Gaia Early Data Release 3. This analysis identified 32 main targets in the SETI ellipsoid. in the southern continuous observation zone of TESS, all with uncertainties refined to better than 0.5 light years.

Although initial examination of the TESS light curves as it crossed the ellipsoid revealed no anomalies, the foundation laid by this initiative paves the way for extending the research to other investigations, to a wider range of targets and the exploration of various types of potential signals.

Applying the SETI Ellipsoid technique to examine large archival databases represents a monumental step forward in the search for technosignatures. Using Gaia’s highly accurate distance estimates, the study demonstrates the feasibility of cross-referencing these distances with other time-domain surveys like TESS to improve monitoring and anomaly detection capabilities in SETI research.

The SETI Ellipsoid method, combined with Gaia’s distance measurements, provides a robust and adaptable framework for future SETI research. Researchers can apply it retrospectively to sift through archival data for potential signals, proactively select targets, and plan future monitoring campaigns.

“As Dr. Jill Tarter often points out, SETI searches are like looking for a needle in a 9-D haystack,” said co-author Dr. Sofia Sheikh. “Any technique that can help us prioritize where to look, like the SETI ellipsoid, could potentially give us a shortcut to the most promising parts of the haystack. This work is the first step in finding these newly placed parts highlight of the parameter space, and sets an exciting precedent for future large survey projects like the LSST.

The research is published in The astronomical journal.