Using a large array of radio antennas in rural Australia, a group of astronomers has begun the first search for signals from alien technology from galaxies beyond our own.
The SETI Institute, the Berkeley SETI Research Center, and the International Center for Radio Astronomy Research initiated the work. The collaboration makes observations using the Murchison Widefield Array, a 4,096-antenna radio astronomy observatory in Western Australia. The array’s antennas look like a swarm of metallic spiders arranged in a grid; while not as grand as some large radio observatories, the array is well suited for deep space radio observations.
The team’s research, currently hosted on the preprint server arXiv, took advantage of the array’s large field of view to scan 2,800 galaxies in a single observation. This distinguishes the recent study from previous research, which focused on radio sources within the Milky Way. Stars within the Milky Way are between 4 and 100,000 light-years away, while nearby galaxies are between 2 million and 30 million light-years away, so the difference in size is quite large.
“One of the major challenges in searching for signs of extraterrestrial intelligence is the speed at which we can observe the sky,” the team wrote in the paper. “Even though aperture arrays like the MWA offer large fields of view, specialized experiments performed on shared instruments “It also limits how much of the sky we can cover and how often we can cover the same light source.”
According to news released by the SETI Institute, in order for alien civilizations from different galaxies to send messages detectable on Earth, the civilization’s technology needs to be advanced enough to use its host star or several stars as energy. This classification is based on the Kardashev Scale of Progress of Intelligent Life, which describes three basic categories of civilizations and their levels of progress, defined by the energy at their disposal.
The Western Australia Array has previously been used to search for extraterrestrial intelligence, or SETI; in 2020, a comprehensive search for alien signatures was unsuccessful. At the risk of stating the obvious, recent searches have yielded no technological signatures and no indication that aliens are using technology of their own. But if you don’t shoot, you will 100% miss!
Researchers note that current and planned telescopes are increasing the speed of the search. In other words, both the Very Large Array and the MeerKAT telescope will help search for extraterrestrial signals at radio wavelengths. I just hope the aliens are familiar with standard radio communication protocols – “roger”, “over”, etc. Otherwise, when things are bad enough for humanity, we’ll get stuck in an airplane routine of dealing with aliens.
