Scientists Are Using Ten Possible Futures of Earth to Figure Out How We Might Detect Alien Technology

Searching for signs of extraterrestrial intelligence has always been a challenging scientific goal. While we’ve made enormous progress in discovering exoplanets and analyzing their atmospheres, finding clear evidence of technology beyond Earth, known as technosignatures, remains extremely difficult. A recent scientific study takes a fresh and surprisingly practical approach to this problem by asking a simple but powerful question: What would Earth look like to distant observers 1,000 years from now?

A new paper by Jacob Haqq-Misra of the Blue Marble Space Institute of Science and his collaborators explores this idea through a framework called Project Janus. The study has been accepted for publication in The Astrophysical Journal Letters and is currently available as a preprint on arXiv. Instead of speculating wildly about alien civilizations, the researchers focus on future versions of humanity itself, using Earth as a reference point to understand what kinds of technological signals might be detectable on distant Earth-like planets.

What Is Project Janus and Why It Matters

Project Janus is a structured attempt to imagine ten distinct scenarios for Earth’s future roughly 1,000 years from now. These scenarios are not predictions but plausible trajectories based on current technological, environmental, and societal trends. Importantly, all ten futures assume that humans still exist and that civilization has not fully collapsed.

The scenarios span a wide range of possibilities. On one extreme is an industrial dystopia, where atmospheric carbon dioxide levels soar into the tens of thousands of parts per million. On the other extreme is an ecological civilization, where human activity leaves almost no detectable technological footprint and Earth appears nearly indistinguishable from its pre-industrial state.

The goal is not to judge which future is better, but to understand what kinds of signals each version of Earth would send into space—and whether those signals could be detected by telescopes being planned or built today.

The Baseline: Observing Earth From 32.6 Light-Years Away

To make the analysis realistic, the researchers modeled Earth as if it were orbiting a Sun-like star 32.6 light-years away. This distance was chosen because it is close enough for next-generation observatories to plausibly study Earth-sized exoplanets in detail.

For each of the ten Project Janus scenarios, the team asked a critical question: What technosignatures would escape Earth’s atmosphere or surface, and could we detect them from that distance? To answer this, they evaluated four major observational approaches—some already under construction, others still conceptual.

Habitable Worlds Observatory and Atmospheric Pollution

One of the most promising tools discussed in the paper is NASA’s planned Habitable Worlds Observatory (HWO). This next-generation space telescope is specifically designed to study the atmospheres of Earth-like exoplanets.

In eight out of the ten future Earth scenarios, HWO would likely be able to detect nitrogen dioxide (NO₂) in the atmosphere. NO₂ is a strong indicator of industrial activity, produced by fossil fuel combustion and other large-scale manufacturing processes. On a planetary scale, its presence could be difficult to explain without technology.

In some extreme cases, such as a planet-wide city known as an ecumenopolis, HWO might even detect sodium emission lines caused by artificial nighttime lighting. However, in the more environmentally balanced scenarios, the observatory would struggle to distinguish a technologically advanced planet from one that simply hosts microbial or simple biological life.

Radio Astronomy and the Limits of Detection

Radio signals have long been associated with the search for extraterrestrial intelligence, but the study highlights some sobering limitations. The Square Kilometre Array (SKA), set to become operational around 2028, will be the most powerful radio telescope ever built.

Despite its capabilities, radio signals weaken dramatically over interstellar distances. The researchers found that routine radio communications, such as those used for satellites or planetary probes, would be nearly impossible to detect unless a civilization was intentionally broadcasting toward Earth.

Only in a couple of the Project Janus scenarios do civilizations actively attempt to communicate with others in the galaxy. In those cases, SKA could potentially detect directed signals, but this would still require long observation times and favorable assumptions.

LIFE and the Detection of Industrial Chemicals

Another observatory concept examined in the study is LIFE (Large Interferometer for Exoplanets), a proposed European Space Agency mission. LIFE would operate as a space-based infrared interferometer, allowing it to detect very specific atmospheric chemicals.

This includes chlorofluorocarbons (CFCs) and carbon tetrafluoride (CF₄)—both strong indicators of industrial activity. CF₄, in particular, is associated with large-scale agriculture and industrial processes and would be extremely difficult to produce through natural means.

In two of the Project Janus scenarios, these gases build up to detectable levels, making LIFE a powerful tool for identifying advanced civilizations through chemical fingerprints.

The Solar Gravitational Lens and Direct Imaging

The most ambitious concept discussed in the paper is the Solar Gravitational Lens (SGL) observatory. This idea involves sending a spacecraft more than 600 astronomical units from the Sun, using the Sun’s gravity to magnify light from a distant exoplanet.

While still theoretical and unsupported by any space agency, SGL could produce low-resolution images of an exoplanet’s surface. Unlike other observatories that see only a few pixels, SGL could potentially reveal urban sprawl, massive infrastructure, or orbital megastructures.

The downside is the timescale. With current propulsion technology, reaching the correct position would take around 70 years, and the mission would likely take decades more to return usable data.

Understanding Technosignatures Beyond Radio Signals

One of the strengths of this study is its broad definition of technosignatures. Instead of focusing solely on radio transmissions, the researchers consider atmospheric pollution, artificial lighting, industrial chemicals, and surface structures.

This approach reflects a growing consensus in the scientific community that passive signs of technology may be far more common and detectable than intentional communication attempts.

Why This Research Changes How We Search for Alien Life

By grounding technosignature searches in realistic futures of Earth, this study provides a practical roadmap for upcoming observatories. It helps scientists prioritize which signals are most likely to exist and which instruments are best suited to detect them.

Rather than asking what alien civilizations might do, the paper asks what we ourselves might look like from afar—a far more testable and grounded strategy.

As future telescopes come online, frameworks like Project Janus could play a crucial role in one of humanity’s biggest scientific questions: Are we truly alone in the universe, or are other technological civilizations quietly leaving detectable traces among the stars?

Research Paper:
https://arxiv.org/abs/2511.20329