We’re still in the early days of searching for life elsewhere. The Perseverance rover is on its way to a paleo-delta on Mars to look for fossilized signs of ancient bacterial life. SETI’s been watching the sky with radio dishes, listening for signals from distant worlds. Our telescopes are beginning to scan the atmospheres of distant exoplanets for biosignatures.
Soon we’ll take another step forward in the search when new, powerful telescopes begin to search not just for life but for other civilizations.
The search for biosignatures is gaining momentum. If we can find atmospheric indications of life at another planet or moon—things like methane and nitrous oxide and a host of other chemical compounds—then we can wonder if living things produced them. But the search for technosignatures raises the level of the game. Only a technological civilization can produce technosignatures.
Technosignatures are simply the effects of technology on an environment. Light from massive cities, particular atmospheric chemicals, and even satellites orbiting a planet are all technosignatures. The granddaddy of all technosignatures is probably the Dyson Sphere. A Dyson Sphere is a hypothetical megastructure surrounding a star and capturing its solar energy output. The idea is that as a civilization grows, its energy requirements will balloon, and the only way to gather the energy the civilization requires is to surround its star with an energy-gathering sphere.
Artist’s impression of a Dyson Sphere. The construction of such a massive engineering structure would create a technosignature that humanity could detect. Credit: SentientDevelopments.com/Eburacum45
In 2021, the National Academies of Sciences released their Decadal Survey on Astronomy and Astrophysics 2020, called Astro2020. They release one every ten years, and each survey outlines the critical challenges in astrophysics and astronomy for the next decade. Astro2020 contains several recommendations that can advance the search for technosignatures. A NASA working group has released a white paper digging into the technosignature part of Astro2020.
The paper is titled “OPPORTUNITIES FOR TECHNOSIGNATURE SCIENCE IN THE ASTRO2020 REPORT.” It comes from Nexus for Exoplanet System Science (NExSS). NExSS is a multidisciplinary group that includes Earth scientists, planetary scientists, heliophysicists, and astrophysicists. They bring a collaborative and synthesized approach to the search for biosignatures and technosignatures.
“Technosignatures refer to any observable manifestations of extraterrestrial technology, and the search for technosignatures is part of the continuum of the astrobiological search for biosignatures,” the paper says. “The search for technosignatures is directly relevant to the “World and Suns in Context” theme and “Pathways to Habitable Worlds” program in the Astro2020 report.”
The white paper aims to “… demonstrate the relevance of technosignature science to a wide range
of missions…” The NExSS group is urging the larger science community to include the search for technosignatures in the design and implementation of projects like LUVOIR, ELTs, infrared and x-ray observatories, and other similar facilities.
A mission concept poster for NASA’s LUVOIR telescope. LUVOIR will see in optical, ultraviolet, and infrared, making it a powerful and versatile telescope. Image Credit: NASA/GSFC
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