Dyson sphere megastructure
An artist’s representation shows a megastructure known as a Dyson sphere capturing the energy from a distant star. Such a structure could create observable technosignatures pointing to the civilization behind its construction. (Credit: Danielle Futselaar / SETI International)

It’s been a quarter-century since Congress cut off NASA funding for the search for extraterrestrial intelligence, or SETI, but now the space agency is revisiting the topic under another name: technosignatures.

“I’m excited to announce that NASA is taking the 1st steps to explore ways to search for life advanced enough to create technosignatures: signs or signals, which if observed, would let us infer the existence of technological life elsewhere in the universe,” Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate, said in a tweet today.

The search is the focus of a workshop taking place this week at the Lunar and Planetary Institute in Houston, with experts on the search for exoplanets, artificial radio signals and other potential pointers in attendance. House Science Committee Chairman Lamar Smith, R-Texas, is due to give a welcome message.

That’s a far cry from 1993, when a congressional effort spearheaded by Sen. Richard Bryan killed off NASA’s 10-year SETI program, which was known as the High Resolution Microwave Survey, or HRMS. “This hopefully will be the end of Martian hunting season at the taxpayer’s expense,” Bryan declared at the time.

Previously: Scientists expand their spectrum in the search for alien life

Since then, much has changed: Philanthropists including Microsoft co-founder Paul Allen and Seattle tech pioneer Nathan Myhrvold kept the SETI search alive. Ironically, NASA turned its focus to the search for life’s signatures on Mars (which was never a target of NASA’s SETI campaign). And astronomers started discovering planets beyond our solar system, including many that seem potentially habitable.

NASA’s Kepler and TESS missions are in the forefront of the search for alien Earths — but as lists of potentially habitable planets grow, how can scientists determine which worlds actually harbor life, based on observations made from a distance of light-years?

That’s the subject of a mounting pile of research papers. Some studies suggest looking for the spectral signs of chemical disequilibrium in the atmospheres of alien planets, or thermodynamic disequilibrium that could point to the existence of an energy-intensive civilization. Others call for seeking out signatures of bad behavior ranging from global warming and nuclear blasts to air pollution and light pollution from alien cities.

One well-known case even led scientists to consider whether an alien megastructure was behind the seemingly puzzling pattern of fluctuations in a distant star’s brightness. (They eventually dropped the idea.)

And then there are the traditional SETI strategies used in the 58-year-long search for artificial patterns in faraway radio or laser emissions.

NASA said this week’s proceedings are aimed at “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,” the space agency said in its workshop preview.

The Breakthrough Initiatives, backed by Russian billionaire investor Yuri Milner and other tech heavyweights, are sure to figure in that part of the equation. One of the initiatives, Breakthrough Listen, is putting $100 million into a 10-year SETI campaign. Executive director Pete Worden, who previously served as director of NASA Ames Research Center, is among the speakers at this week’s event.

Other presenters are coming from the California-based SETI Institute, which built the radio-scanning Allen Telescope Array with early support from Allen and Myhrvold; and the Seattle-based Blue Marble Space Institute of Science, which has been focusing on the technosignature issue and other cosmic questions.

The workshop gets started bright and early on Wednesday, and there’ll be a Reddit AMA chat at 1 p.m. ET (10 a.m. PT) Thursday. NASA is promising that the entire proceedings will be live-streamed. Which means even E.T. could tune in.

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