A team of international scientists from the Search for Extraterrestrial Intelligence (SETI) is preparing to use the world’s biggest radio telescope – the Five-hundred-meter Aperture radio Telescope (FAST) in China – boosting international efforts to find alien life.
Opened in 2016, FAST has so far been used exclusively by Chinese scientists. That’s set to change next year with the commencement of a joint project between researchers from the SETI Institute in the U.S., the Chinese Academy of Sciences, as well as scientists working on the Breakthrough Listen Initiative – a project dedicated to SETI.
The team recently unveiled its plans, detailing the unprecedented advantages of the radio telescope in a paper published in the Research in Astronomy and Astrophysics.
SETI scientists target three sets of observations
The team plans to observe different targets: the Andromeda galaxy, star systems with exoplanets orbiting in the potentially habitable zone and modulated radio signals that were not detected in previous SETI efforts.
The Andromeda galaxy, located around 2.5 million light-years from Earth, is ripe for study as the signals coming out of it have been ignored in previous SETI efforts, according to co-author Vishal Gajjar, a research fellow at the University of California, Berkeley, who’s part of the Breakthrough Listen Initiative. This is because signals from the Andromeda galaxy are too weak to be picked up using most instruments.
FAST’s enhanced sensitivity, however, could allow astronomers to detect those weaker signals, provided that they are generated by a planet consuming at least 1019 watts of power. That’s more than Earth’s annual energy consumption, but for more advanced civilizations, it’s considered on the low side.
The radio telescope’s 19-beam receiver can also allow researchers to survey the more than one trillion stars said to be in Andromeda. The sheer number of stars is a lot to comb through, but the receiver can be pointed at different points in the sky. All told, surveying the entire galaxy could only take as few as 14 hours.
Next, the researchers are going to observe exoplanets orbiting in a star’s habitable zone, the orbital region around a star where planets could have stable atmospheres to support liquid water. Liquid water is essential to life, so exoplanets in habitable zones have always interested SETI scientists.
The team has narrowed down their targets by selecting exoplanets that orbit stars identified through the space-based Transiting Exoplanet Survey Satellite (TESS). At 100 to 200 light-years away, TESS-identified stars are less distant compared to many of those discovered using the Kepler space telescope.
The team’s last target is looking for modulated radio signals. Modulation refers to the process of converting data into radio waves. Doing so allows comprehensible data, such as music, to be transmitted. Two common forms are amplitude and frequency modulation, which are used in radio broadcasting (AM and FM radio).
With FAST’s sensitivity and new machine learning algorithms, the researchers could identify modulated signals of unknown origin. If they’re able to do so, the next challenge is to decode these signals for potentially meaningful data. Aliens might be using a modulation technique that’s completely unknown or advanced to man, so that’s something that experts will have to consider.
Gajjar conveyed his team’s excitement about using FAST. He noted that they were “looking forward to conducting some of the deepest radio studies anyone has ever done before.”
Besides their upcoming work at FAST, the Breakthrough Listen team is also planning to conduct space surveys using MeerKAT, a radio telescope in South Africa that recently received computing upgrades.