Research on detecting extraterrestrial life is advancing with the introduction of a new framework called Project Janus. Developed by Jacob Haqq-Misra from the Blue Marble Space Institute of Science and his colleagues, this framework outlines ten potential scenarios for Earth’s technological landscape 1,000 years into the future. Their findings, which are available in pre-print on arXiv and accepted for publication in The Astrophysical Journal Letters, aim to enhance our understanding of technosignatures—indicators of technology on distant planets.
Project Janus presents a diverse range of possibilities, from a heavily industrialized Earth with elevated carbon dioxide levels to a thriving ecological paradise reminiscent of pre-industrial times. Importantly, all scenarios assume the continued presence of humans, deliberately omitting what might occur if civilization were to collapse entirely within the next millennium.
The authors establish a baseline by focusing on an Earth-like planet located approximately 32.6 light years away from our solar system. They assess which technosignatures could emerge from the evolution of civilization on that planet, depending on the technological pathway it follows. The study further investigates whether current and upcoming observatories would be capable of detecting these signals.
Key Observatories in the Search for Technosignatures
The Habitable Worlds Observatory (HWO), NASA’s next flagship telescope, emerges as a primary candidate for this technosignature search. Designed to analyze the atmospheres of potentially habitable worlds, HWO could identify nitrogen dioxide (NO2), a pollutant associated with industrial activity, in eight out of the ten scenarios. In cases where civilization expands into a planet-wide urban environment, known as an ecumenopolis, HWO might even detect sodium emissions from artificial lighting.
In contrast, scenarios that depict a more ecologically balanced planet present challenges for HWO, as differentiating between advanced technology and natural cellular life could prove difficult.
The study also highlights radio astronomy as a promising avenue for technosignature detection. The Square Kilometer Array (SKA), set to become the most powerful radio telescope when it begins operations in 2028, could help identify signs of intelligent life. However, the authors note that radio waves often lose strength over vast distances. Unless a civilization actively transmits messages towards Earth, the SKA may struggle to distinguish signals intended for its own spacecraft.
While two of the more advanced industrial scenarios do involve intentional communication with other civilizations, the likelihood of detecting such signals remains tenuous.
Innovative Concepts for Future Observations
Another potential tool in the search for technosignatures is the Large Interferometer for Exoplanets (LIFE), a mission concept by the European Space Agency (ESA). LIFE would operate as a long baseline interferometer in space, capable of identifying numerous industrial pollutants, such as chlorofluorocarbons (CFCs) and carbon tetrafluoride (CF4). The presence of CF4, in particular, would suggest large-scale agricultural practices, which feature in two of the Project Janus scenarios.
Lastly, the ambitious Solar Gravitational Lens (SGL) observatory remains a theoretical concept but has garnered increased research interest. If realized, the SGL would operate at a distance 600 times greater than the distance between the Earth and the Sun, utilizing the Sun’s gravitational lens to amplify signals from distant exoplanets. This innovative approach could potentially provide a low-resolution image of a planet, revealing substantial structures indicative of advanced civilizations, such as urban sprawl.
The timeline for developing the SGL is uncertain, and current technologies indicate that a mission could take up to 70 years to reach its destination. As such, significant advancements in technology may be necessary before we can analyze the potential civilizations outlined in Project Janus.
Ultimately, the research presented in this paper lays a foundation for understanding the types of technosignatures we should pursue in our quest for extraterrestrial life. As the development of these observatories progresses, they could facilitate one of humanity’s most profound discoveries: confirmation that we are not alone in the universe.
