Scientists have proposed a new approach to searching for highly advanced extraterrestrial civilizations. Instead of focusing on infrared radiation from giant megastructures (such as Dyson spheres), researchers suggest paying attention to anomalously slow stellar rotation rates.
The core of the Stellar J‑Harvesting hypothesis is that an advanced civilization could extract energy not from a star’s light output, but from its angular momentum — essentially deliberately slowing the star’s rotation. Theoretically, this could be achieved using large‑scale conductive structures interacting with the star’s magnetic field and stellar wind. One example is a giant orbital ring located about one astronomical unit from the star — similar to the distance between Earth and the Sun. Such a system would block almost no light and emit very little excess heat, making it extremely difficult to detect with conventional methods.
Traditional searches for extraterrestrial intelligence rely on detecting an infrared “signature” from hypothetical energy‑harvesting structures, but so far no reliable evidence of such objects has been found. The new method proposes a different indicator: if a megastructure has been extracting rotational energy from a star for decades or centuries, the star’s axial rotation should become noticeably slower compared to similar stars of the same type and age.
To test the idea, scientists analyzed data from nearly 6,700 stars of spectral classes FGK collected by the Kepler telescope. As a result, two objects stood out: KIC 67606183 and KIC 9834255. These stars are similar to the Sun, but their rotation periods are 61–65 days, whereas typical stars of this class rotate once every 5–10 days.
At the same time, the study authors do not claim that the anomaly is caused by extraterrestrial activity. Such slow rotation can have entirely natural explanations — for example, peculiarities in the star’s evolution, unusual chemical composition, or membership in an unresolved binary system. Currently, these objects are merely promising candidates for further observations.
More broadly, the work highlights a key issue in current searches for extraterrestrial intelligence: scientists can only detect signals they are able to theoretically predict and model. If a civilization uses fundamentally different energy management methods — for example, subtle manipulation of a star’s magnetosphere or rotation — existing tools and techniques will likely fail to capture them.
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