Using one of the world’s most sensitive radio telescopes, a group of Australian researchers have gone on the hunt for aliens in the heart of the Milky Way. In late 2020, they pointed their antennas toward the center of the galaxy in search of alien technosignatures.
In its field of view were 144 known exoplanets and potentially billions of stars. But after keeping their eyes in the sky for more than seven hours, they heard nothing that might have seemed extraterrestrial (not even miners).
The search was carried out using the Murchison Widefield Array, a collection of 4,096 spider-shaped antennas placed in the desert of Western Australia. The antennas, arranged in 256 tiles, can pick up low-frequency radio waves from space.
More importantly, the array has a wide field of view, meaning researchers can hear technosignatures (signals emitted by intelligent life) over a huge region of space. >
The search is described in a new paper that appeared yesterday and has been accepted for publication in the Publications of the Astronomical Society of Australia.
This is their fourth attempt. Previously, they surveyed the dark forest of our cosmos back in 2020, analyzing more than 10 million stars, studied the galactic center back in 2013, and searched the Orion Nebula in 2018. No luck with any.
However, the new quest is different in key ways. For example, the previous search attempt for the galactic center, in 2013, only contained 38 known exoplanets, while the new search contains 144.
The search for life around the center Galactic is particularly useful because the region contains the highest density of stars within our galaxy. Where there are stars, there may be planets, and where there are planets there should be life.
The team used a different survey, known as the Galactic Core, which classified 3.3 million stars. However, this study covers less than 1% of the area studied by the MWA.
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That’s, in theory, plenty of chances to hear from alien friends. However, it is but a drop in the cosmic ocean: there are many other places from which alien technosignatures could emanate.
This is also the first time a search has been done on a high frequency of 155 MHz. Previous searches have focused on lower frequencies, between 98 and 133 MHz. Of course, this comes with a big caveat: the aliens use the same technologies as us.
The MWA is currently in the process of being updated, which will allow searches to be run at different frequencies, giving it the ability to match other technosignature searches.