Loeb’s research is backed up by a 2018 NASA report written after a three-day workshop of more than 60 scientists looking for ways to identify alien life from any time in the universe’s history. Even considering the evidence might already be here on Earth.

The gathered scientists were from various fields including two from NASA. They exchanged ideas and theories about the existence of technosignatures and the role NASA could play in future searches.

The report that came out of the workshop focused on finding ways to identify extraterrestrial existence through technology.

A technosignature is described in four parts in the report:

1. Technosignatures are analogous to biosignatures in that they are a detectable sign of extant or extinct life. Note that while some consider technosignatures to be a subset of biosignatures and others think of them as being complementary to biosignatures, either way searches for technosignatures are logically continuous with the search for biosignatures as part of astrobiology.

2. Technosignatures represent any sign of technology that we can use to infer the existence of intelligent life elsewhere in the universe, including familiar objects of searches for extraterrestrial intelligence such as narrow-band radio signals or pulsed lasers. The term SETI (Search for Extraterrestrial Intelligence) often is used synonymously with the search for technosignatures.

3. As with biosignatures, one must proceed by hypothesizing a class of detectable technosignatures, motivated by life on Earth, and then designing a search for that technosignature considering both its detectability and its uniqueness. The search for technosignatures is thus broad, encompassing much of astronomy.

4. Unlike biosignatures, many proposed technosignatures are self-luminous or involve the manipulation of energy from bright natural sources. Also, since technological life might spread through the galaxy, its technosignatures might be found far in both space and time from its point of abiogenesis. Compared to biosignatures, technosignatures might therefore be more ubiquitous, more obvious, more unambiguous, and detectable at much greater (even extragalactic) distances.

At the end of the workshop at the Lunar and Planetary Institute in Houston, Texas the group published a 70-page report called “NASA and the Search for Technosignatures.”

Also in the report is discussion that extraterrestrial life may already be on Earth. “Because the geological, paleontological, and archaeological records on Earth are so incomplete, it is even possible that the Earth itself hosts such artifacts,” the group concluded in the report. “Although, again, this idea is often conflated with unscientific popular imaginings and science fiction stories about alien visitation, and so must be approached carefully.”