Scientists are taking significant steps toward identifying signs of extraterrestrial life by imagining what Earth may look like in the future. A new paper, recently accepted for publication in The Astrophysical Journal Letters, introduces a framework called Project Janus. Developed by Jacob Haqq-Misra and his colleagues from the Blue Marble Space Institute of Science, this project outlines ten potential scenarios for Earth 1,000 years from now.
The goal of Project Janus is to enhance our understanding of what technological signatures, or technosignatures, might be visible from distant exoplanets. These signatures could indicate advanced civilizations similar to our own. The authors propose a baseline scenario involving an Earth-Sun analog located approximately 32.6 light years away, assessing the potential technosignatures that could arise from various technological developments.
Imagining Diverse Futures
The ten scenarios range from a dystopian world with drastically elevated carbon dioxide levels to a flourishing ecological paradise reminiscent of pre-industrial Earth. Notably, all scenarios maintain human presence, as the study does not account for a complete collapse of civilization.
The authors conducted a detailed analysis to determine which technosignatures might be detectable using existing and upcoming observatories. The Habitable Worlds Observatory (HWO), NASA’s next flagship telescope, is a primary candidate for this search. Designed specifically to analyze the atmospheres of habitable worlds, HWO could potentially identify nitrogen dioxide (NO2) emissions, a pollutant linked to heavy industrial activity, in eight out of the ten scenarios. In cases where civilization has developed into a vast urban environment, known as an ecumenopolis, the observatory may even detect sodium emissions from artificial lighting.
In contrast, in more ecologically balanced scenarios, distinguishing between advanced technology and basic cellular life poses a significant challenge for HWO.
Exploring Technosignatures with Radio Astronomy
Another avenue for identifying technosignatures is through radio astronomy. The Square Kilometer Array (SKA), set to become operational in 2028, will be the most powerful radio telescope to date. However, the authors caution that radio waves diminish over long distances. Unless civilizations actively transmit radio signals aimed at other intelligent life, detecting their communications may prove difficult.
Despite these challenges, two scenarios within Project Janus involve civilizations sending messages to others, keeping the possibility of detecting such signals open.
The Large Interferometer for Exoplanets (LIFE), a mission concept under the European Space Agency, also offers potential. Designed as a long baseline interferometer in space, LIFE could identify industrial pollutants, including chlorofluorocarbons (CFCs) and carbon tetrafluoride (CF4). These pollutants could serve as indicators of advanced industrial civilizations, particularly in scenarios involving large-scale agriculture.
The most ambitious observatory concept discussed is the Solar Gravitational Lens (SGL) observatory. Although still in the conceptual stage and lacking formal support from space agencies, the SGL could potentially travel 600 times farther from the Sun than Earth. By utilizing the Sun’s gravitational lensing effect, it could capture images of exoplanets, revealing vast structures such as orbital rings or sprawling urban areas.
Though the SGL represents the most powerful option, its development timeline may extend well into the future, possibly requiring a significant portion of the next millennium.
Ultimately, the researchers emphasize the importance of understanding these potential technosignatures as observatories advance. The hope is that one or more of these projects may eventually lead to a groundbreaking discovery: definitive evidence that humanity is not alone in the universe.
