Breakthrough Listen uses radio telescopes like the Parkes Telescope in Australia or the Green Bank Observatory in West Virginia. These instruments regularly detect what looks like signals from space, but are actually due to local interference from the ground. In April and May 2019, the team captured something else – a narrow beam transmission around 980 MHz that lasted 30 hours. The signal, called BLC1, also seemed to shift in such a way that it could have come from a planet orbiting the star.
The team is still preparing a paper that the scientific community can examine, but there are a few reasons to be excited here. Proxima Centauri is the closest star to our solar system, and in 2016, scientists announced the discovery of an Earth-like exoplanet orbiting the habitable zone. Later, astronomers saw another larger planet further out in the solar system. So it is theoretically possible that there is life on one of these planets, especially the one in the habitable zone.
However, it is still too early to start celebrating the discovery of alien life. BLC1 is one candidate signal to be analyzed, and if we are realistic, it is doubtful that intelligent aliens live in the next solar system above. The Milky Way galaxy has an estimated 300 million exoplanets and is nearly 14 billion years old. Finding another intelligent species that existed at the same time as us, just a few light years away, would be highly unlikely. If the strangers also use radio frequency technology at the same time as we are, it’s an even greater coincidence.
This is not the first signal that could be interpreted as having artificial origin. The famous “Wow” signal, discovered in 1977 by SETI researchers, is another example. One did not go out, but BLC1 could be the first serious challenger in decades. If this is not the case then maybe there are many more stars out there. The only way we find them is to keep looking.