Ilaria Rosella Pagliaro New studies suggest that silicon solar panels on extraterrestrial planets could constitute a detectable technology signature
If extraterrestrial beings exist, they might very well harness solar energy just as we do. Imagine silicon solar panels covering vast areas of distant planets, creating technological signatures detectable by our telescopes. This intriguing possibility has been explored by NASA researchers in a recent study. Could this unconventional approach revolutionize how we search for extraterrestrial life?
The study
The article, titled “Detectability of Solar Panels as a Technosignature,” was published in The Astrophysical Journal. The lead author is Ravi Kopparapu from NASA’s Goddard Space Flight Center.
In their study, the authors evaluate the potential to detect silicon-based solar panels on a planet within a habitable zone similar to Earth’s. Silicon photovoltaic cells reflect a significant amount of light in the ultraviolet, visible, and near-infrared spectra, making them detectable by space missions like the Habitable Worlds Observatory (HWO). This mission aims to identify and photograph Earth-like planets in habitable zones.
Assumptions and hypotheses
Naturally, the authors make several assumptions about a hypothetical extraterrestrial civilization using solar energy. They assume the use of large-scale silicon-based solar panels and that the planet orbits a star similar to our Sun. Silicon panels are cost-effective to produce and well-suited to harness the energy of a Sun-like star.
Energy requirements and detection challenges
The authors explain that to generate enough energy for our needs on Earth, only 2.4% of Earth’s surface would need to be covered by silicon solar panels. However, to detect such coverage on an exoplanet, a telescope like the HWO would require hundreds of hours of observation. Even if a planet were 23% covered by solar panels, distinguishing the planet’s light from that of the star would still be very challenging.
Furthermore, with advancing technology, an extraterrestrial civilization might cover less of their planet’s surface to generate the same amount of energy, making detection even more difficult.
Conclusion: the improbability of detecting solar panels
Ultimately, it is unlikely that silicon-based solar panels on a planetary surface would create an easily detectable technological signature. Even with an advanced telescope and many hours of observation, distinguishing signals from a planet with high solar panel coverage would be extremely difficult. As the authors explain:
“We find that, even with significant population growth, the energy needs of human civilization would be several orders of magnitude lower than the energy threshold for a Kardashev Type I civilization or a Dyson sphere that harnesses a star’s energy.”
According to this theory, advanced civilizations require ever-increasing amounts of energy and eventually construct enormous structures to capture all the available energy from their star. However, the results of this research suggest we may never see one of these structures because they may not be necessary.
Source: The Astrophysical Journal
