In the 1997 movie Contact, a scientist, played by actress Jodie Foster, detects a radio signal—the first communication from an extraterrestrial(外星的)civilization. That story, composed by Carl Sagan, is a fiction. But the search for such a signal is not a crazy story. Real scientists look to the sky, using powerful radio telescopes, hoping to hear even a whisper of a radio signal from one of our neighbor planets.
Indeed, a recent report of a transmission originating from Proxima Centauri, the closest star to our own, was reported by the British newspaper The Guardian in December. The source of the story is not a scientific paper, but instead it seems to have been leaked by an unknown source. The claim of a signal, if it turns out to be truly a sign of extraterrestrial intelligence, would be one of the most important discoveries of all times.
In April and May of 2019, the 64-meter-wide Parkes radio telescope, located in Australia, was recording radio transmissions from the direction of nearby star Proxima Centauri. Over the course of hours, the telescope documented data from the star every half an hour, before staying away to look at a different direction. This procedure, called "nodding" was used to make sure that any observed signal is coming from a particular direction, rather than just random radio noise.
This signal was not immediately noticed; it was over a year after the data was recorded that Shane Smith, an assistant with Breakthrough Listen, found it buried in the telescope's recordings. This was in late October 2020. So, what exactly was seen? It was a radio signal at a single frequency, specifically 980. 002 MHz. It was observed to have originated in a small patch of the sky, about half the diameter(直径)of the full moon, centred on Proxima Centauri.
First and foremost, it is important to note that astronomers think it is highly unlikely that the signal is caused by space aliens trying to communicate with us. However,astronomers mentioning the significance of the signal cannot be ignored.
