The search for evidence of extraterrestrial technology, known as technosignatures, has taken a significant step forward with the introduction of a new framework by researchers. In a paper accepted for publication in The Astrophysical Journal Letters, Jacob Haqq-Misra from the Blue Marble Space Institute of Science and his co-authors outline their framework, dubbed Project Janus. This initiative aims to predict what Earth might look like in 1,000 years, thereby informing the search for similar technological advancements on other planets.
Project Janus defines ten potential scenarios for Earth’s future, ranging from a heavily industrialized dystopia with atmospheric carbon dioxide levels soaring into the tens of thousands, to an ecological paradise that closely resembles pre-industrial Earth. Importantly, all scenarios assume the presence of human civilization, without exploring the consequences of a complete societal collapse.
To assess potential technosignatures, the researchers focus on an Earth-Sun analog located approximately 32.6 light years away. They examine how the technological evolution of a civilization on that planet might manifest and what observable signs could be detected by upcoming observatories.
Key Observatories for Detection
One of the most promising candidates for detecting technosignatures is the Habitable Worlds Observatory (HWO), NASA’s future flagship telescope designed specifically to analyze the atmospheres of potentially habitable worlds. According to the researchers, nitrogen dioxide (NO2), a pollutant linked to intense industrial activity, would be identifiable in eight out of the ten scenarios outlined by Project Janus. In instances where a civilization has transformed its planet into a vast urban expanse, known as an ecumenopolis, the HWO might even detect sodium emissions from artificial lighting.
In contrast, distinguishing between technologically advanced and biologically rich planets could prove challenging in more eco-friendly scenarios.
The paper also highlights the potential of radio astronomy in the search for technosignatures. The Square Kilometer Array (SKA), anticipated to be the most powerful radio telescope upon its launch in 2028, could play a critical role. However, the authors caution that radio waves lose intensity over long distances. Unless a civilization intentionally transmits radio frequency messages towards Earth, the SKA may struggle to differentiate between signals meant for communication and those directed at its own space probes.
While two of the proposed scenarios do involve civilizations actively sending messages to others, the authors note that this approach carries numerous assumptions.
Another significant tool in the search for technosignatures is the Large Interferometer for Exoplanets (LIFE), a mission concept from the European Space Agency (ESA). Designed to function as a long baseline interferometer in space, LIFE could detect various industrial pollutants, including chlorofluorocarbons (CFCs) and carbon tetrafluoride (CF4). These substances would indicate the presence of an industrial civilization, particularly CF4, which is associated with large-scale agriculture identified in two of the Project Janus scenarios.
The most ambitious of the proposed observatories is the Solar Gravitational Lens (SGL). Although still in conceptual stages and lacking formal support from any space agency, this observatory could potentially travel 600 times farther from the Sun than Earth. By leveraging the Sun’s gravitational lens, it could amplify signals from distant exoplanets, providing a low-resolution image of features such as orbital rings or urban developments on those worlds.
Implications for the Search for Life
While the SGL is a distant prospect, it underscores the necessity of long-term planning in the search for extraterrestrial life. The authors suggest that it may take a significant portion of the next millennium before we can gather data from the civilizations theorized in Project Janus. Current technology would require about 70 years to reach the SGL, making it a long-term endeavor.
Ultimately, this research framework lays the groundwork for understanding the types of technosignatures that may exist beyond our planet. As observatories like the HWO, SKA, and LIFE progress through their development cycles, keeping these potential discoveries in mind could lead to groundbreaking revelations. The possibility of confirming that humanity is not alone in the universe remains a tantalizing prospect for scientists and the public alike.
