Emily Chan
Scientists are searching for alien life in more than 1,300 galaxies. The hunt for any extraterrestrial signals has helped narrow down how many existing advanced civilizations we can expect beyond Earth.
The search was conducted with the Murchison Widefield Array (MWA) in Australia by the SETI Institute, the Berkeley SETI Research Center and the International Center for Radio Astronomy Research.
It aimed to detect low radio frequencies in the 80 to 300 MHz range. Typically, alien signals are looked for in the 1,420 MHz hydrogen emission frequency. Lower frequencies have remained largely unexplored.
The search team focused their attention on a 30-degree field in the constellation of Vela the Sails, which spanned across 2,880 galaxies. The distances to 1,317 of these galaxies have been accurately measured before, so they had a better idea of the power of any transmitters in those galaxies.
The team failed to detect an extraterrestrial signal. They would’ve been able to detect one if it had a transmitter power of 7 x 10^22 watts at a frequency of 100 MHz.
“This work represents a significant step forward in our efforts to detect signals from advanced extraterrestrial civilizations,” said Chenoa Tremblay with the SETI Institute in California. “The large field of view and low-frequency range of the MWA makes it an ideal tool for this kind of research, and the limits we set will guide future guidelines.”
For 64 years, the search for alien life has been concentrated on stars in our own galaxy, the Milky Way. However, in recent areas, the search zone has expanded. For instance, in 2015, the Glimpsing Heat from Alien Technologies project used NASA’s Wide-field Infrared Survey Telescope to assess 100,000 galaxies for civilizations. None were ever found.
In 2023, a team of scientists from the National Chung Hsing University in Taiwan suggested that there could not be more than one civilization within three billion light-years of us that is pointing a radio transmitter at the Milky Way with power above 7.7 x 10^26 watts.
That same year, a search of background galaxies was conducted by leaders of other institutions. They determined the maximum detectable power was at a range of about 10^23 watts to 10^26 watts. Finally, another team used the Green Bank Telescope to search 97 galaxies but detected nothing.
Sign up for Chip Chick’s newsletter and get stories like this delivered to your inbox.
