Posted by A new study from Sejong University proposes a different way to think about the search for extraterrestrial intelligence. Instead of asking only whether a planet could support life, astronomers may also need to consider whether its sky offers the kinds of observable phenomena that could help an intelligent species develop astronomy and science.
Professor Woong-bae Zee introduces the concept of “developmentability”: the idea that an exoplanet’s astronomical environment could influence how easily a technological civilization learns about its place in the universe; habitability describes whether life could survive, while developmentability asks whether that life would have useful observational clues for building a scientific understanding of the cosmos. The study focuses on apparent retrograde motion, when a planet temporarily seems to reverse direction against the background stars. From Earth, Mars and other planets display this behavior because planets move around the Sun at different orbital speeds. Historically, such motions challenged simple Earth-centered models of the Solar System and became important clues in the development of heliocentric astronomy. Zee therefore asked whether observers on potentially habitable exoplanets could witness similarly obvious planetary motions in their own skies. Using orbital and physical data from the NASA Exoplanet Archive, the study calculated how neighboring planets would appear from rocky worlds in or near their stars’ habitable zones. The analysis considered not only whether retrograde motion would occur, but whether it would last long enough, span a large enough angle, appear sufficiently separated from the host star, and be bright enough to see with the naked eye.
Two nearby systems stood out. From GJ 1002 b, about 16 light-years away, a hypothetical observer could see the neighboring planet GJ 1002 c undergo clear retrograde motion. A similar view may be possible from Teegarden’s Star c, roughly 12.5 light-years away, where observers could watch Teegarden’s Star d appear to reverse course.
The study does not suggest that intelligent life actually exists on either world. Instead, it expands SETI thinking by asking whether some planetary systems may provide especially favorable conditions not just for life, but for the emergence of scientific civilizations capable of understanding – and perhaps communicating across – the universe.
For more details, read the full article by Sejong University.
