IAUS 404 Symposium and Agnostic Technosignatures

Last week (2-6 March 2026), I attended the online IAUS 404 symposium hosted by the Blue Marble Space Institute of Science. The conference was about the search for indications of non-terrestrial technology (i.e., technosignatures). The sessions covered a variety of topics, including traditional radio searches for technosignatures (radio SETI), searching for evidence of industrial pollutants in exoplanetary atmospheres, and technosignatures in the solar system, which is the field that is most relevant to my expertise as a planetary scientist. There were also more speculative discussions, ranging from looking for exhaust heat from Dyson spheres to Unidentified Aerial Phenomena (UAPs). There were also discussions about distinguishing between biosignatures and technosignatures. What I most took away from the conference is how interdisciplinary the field is, which is a parallel to planetary science. Another parallel to planetary science thinking beyond our earth bound assumptions. How do we detect technosignatures that don’t come from a civilization like our own?

This past week, I had the privilege of attending the IAUS 404 symposium hosted by the Blue Marble Space Institute of Science (March 2-6 2026) on SETI and technosignatures. As a planetary scientist, the talks which stood out most to me were talks related to solar system science. Several talks covered using ML models to search for anomalies on planetary surfaces which could be potential technosignatures. There was also discussion of distinguishing a biosignature from a technosignature on a planetary surface. This was particularly interesting since it reveals how the difference between biology and technology is more like a spectrum than a clear categorical distinction.

When thinking about how to detect extraterrestrial intelligence, we typically think of advanced technology that only humans build, like interplanetary spacecraft or radio telescopes, but other organisms also construct artificial structures. Beavers build dams, termites build mounds, etc. If technology is defined mainly as an organism extending their limbs by augmenting elements of the natural world to accomplish a task (when you use a hammer you are essentially “augmenting” another limb), beaver dams or termite mounds could arguably be technosignatures, albeit not the technosignatures we might have in mind.

While attending the conference, I was struck by two parallels between planetary science and the broader field of SETI. One parallel is the interdisciplinary nature. The other parallel is the need to think beyond parochial, Earth-centric categories.

Planetary science draws upon the fields of astronomy, geology, chemistry, meteorology, and even biology to understand planetary processes. This is because planets are complex systems.with their own geochemical, atmospheric, and geological cycles. We also need to understand planetary orbits and the orbits of the moons around their parent planets since they also affect planetary processes.

The climates of Earth and Mars are impacted by Milankovitch cycles, because of gradual changing in the shape of their orbits and their axial tilt, leading to changes in climate. The moons of the giant planets are affected by gravitational influences between the other moons and the parent planet, or tides, leading to tidal heating and possible subsurface oceans. Understand the influence of tidal forces on the icy moons was a major part of my research as an intern at JPL and my doctoral work at the University of North Dakota.

In a similar way, SETI is also interdisciplinary since it draws from all the field of study needed to search for and understand extraterrestrial civilizations. We must understand astronomy and planetary science so that we know where to look. We must understand biology and ecology so that we know how extraterrestrials would function and evolve. We must also understand sociology and engineering to understand what they would build and what choices their societies might make. Since many technosignatures, like Dyson spheres and space garbage, are archaeological in nature, we also need to think about archaeology and how things are preserved.

The other parallel is more philosophical in nature and it has to do with the need to move beyond our planetary context. When I participated in a planetary geologic mapping workshop in Flagstaff, AZ a few years ago, I learned that in planetary mapping descriptions of geological featues must be carefully distinguished fom interpretation.

This is because we cannot actually land on the surface and walk up to a geologic feature and confirm what it is and how it formed. A feature that looks like a volcano or a river channel on one planet may have been formed by a completely different process. For example, channels on Mars that look like erosion channels formed by running water were actually formed by the sublimation of carbon dioxide ice. There are also features on other planetary bodies that don’t have a clear parallel on Earth, like double ridges on icy moons, the coronae on Miranda and Venus, or the spider-like araneiform features on Mars.

For this reason, when exploring planetary surfaces we need to avoid premature interpretations based on descriptions. Something might look like a river channel on Mars or Titan, but it might have been formed by a completely different process. This means that each planet is unique and has its own geological features and processes. We cannot assume each planet is the same.

This same principle is also true of extraterrestrial civilizations. One example is the assumption that evidence of technosignatures will come from the disruption of nature. Most technosignatures tend to either be the result of pollution, like CFCs in an exoplanet atmosphere, or radical alterations of nature. Building a Dyson sphere, for example, would likely require the deconstruction of half a planet the size of Mercury to get the requisite materials. A topic that came up during the symposium was the possibility that a civilization might develop its technology in a way that enhances nature rather than disrupting it. Civilizations that build Dyson spheres may exist but be relatively rare compared to civilizations that advance though pathways that are less obvious at interstellar distances.

This bias towards technosignatures that our civilization would recognize as obvious is also true for planetary technosignatures. It is easy to assume that structures built by a non-terrestrial civilization will resemble human-made structures, but the way humans build structures may also be a consequence of the human body plan. Aliens shaped more like termites, for example, might build something that looks more like a giant termite mound.

In astrobiology there is an emerging concept called an agnostic biosignature. It is a biosignature that can be detected which is not necessarily organic or carbon-based. Agnostic biosignatures attempt to identify life as we don’t know it, that is, independent of their specific biochemical pathway. An popular example of life as we don’t know it is silicon-based life, a hypothetic form of life where silicon replaces carbon in its biochemistry.

In the same way, could a methodology for detecting an agnostic technosignature be developed? Common technsignatures are those we would expect from industrial civilizations like ourselves that pollute the environment and radically alter nature. Could there be a way to identify technosignatures that don’t assume this or any particular technological pathway? That will be the topic for a future ML project.

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