Is this an alien radio signal from a super-Earth exoplanet?

Did China’s FAST radio telescope uncover an alien radio signal from the super-Earth exoplanet K2-155 d? The intriguing narrowband radio signal was detected in the direction of the super-Earth, located 238 light-years away. The signal met several criteria for an extraterrestrial origin, but other details suggest it is most likely terrestrial interference.

Using a new machine-learning algorithm, scientists initially narrowed a list of 139,127 candidates down to just two promising signals. After further analysis, K2-155 d emerged as the most promising candidate. The signal was very narrow, which is rare for natural sources and usually artificial in origin. Additionally, the signal exhibited a Doppler shift, indicative of terrestrial interference.

However, there were a few factors suggesting the signal could be of alien origin. For instance, the signal was isolated in one sky location, indicating it was not terrestrial interference. Moreover, despite being detected at only one polarization channel, the signal was still unusual.

Yet, there were also signals at three other nearby stars, suggesting terrestrial interference was a more likely explanation. The researchers acknowledged that they don’t know what produced the signal, leaving its origin unknown for now. While the evidence leans towards terrestrial interference, the possibility of an alien signal cannot be entirely ruled out.