Astronomers using the Murchison Widefield Array in Western Australia have searched for alien signals at a 10 kHz spectral resolution originating from a population of about 2,800 galaxies toward the Vela supernova remnant.
This illustration shows what the activities of a Kardashev Type III civilisation might look like – encapsulating the energy of stars by so-called Dyson spheres is one way to harness enormous energies on galactic scales; the resulting waste heat products should be detectable by telescopes. Image credit: Danielle Futselaar / ASTRON.
“When we consider the search for intelligent life beyond Earth, we often consider the age and advancement of technology that may produce a signal detectable by our telescopes,” said Dr. Chenoa Tremblay from the SETI Institute and Professor Steven Tingay from Curtin University.
“In popular culture, advanced civilizations are portrayed as having interstellar spacecraft and communications.”
“In the 1960s, the astrophysicist Nikolai Kardashev proposed the scale to quantify the degree of technological advancement of intelligent life beyond Earth.”
“The Kardashev scale has three levels: Type I civilizations are capable of accessing all the energy available on their planet (upward of 1016 W); Type II civilizations can directly consume a star’s energy (upwards of 1026 W); and Type III civilizations can capture all the energy emitted by their galaxy (upward of 1036 W).”
“Civilizations on the upper end of the Kardashev scale could produce large quantities of electromagnetic radiation detectable at galactic distances.”
“Some of the ideas explored in the past involve harnessing their galaxies’ starlight, colonizing their solar system, or using pulsars as communication networks.”
“The ability for radio waves to permeate space over long distances and through planetary atmospheres made them a practical method for searching for interstellar communication.”
The authors used the Murchison Widefield Array (MWA) to search for signs of alien technology in galaxies beyond the Milky Way focusing on low radio frequencies (100 MHz).
They covered about 2,800 galaxies in one observation, of which 1,300 they know the distance to.
“This work represents a significant step forward in our efforts to detect signals from advanced extraterrestrial civilizations,” Dr. Tremblay said.
“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 studies.”
The work appears in the Astrophysical Journal.
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C.D. Tremblay & S.J. Tingay. 2024. An Extragalactic Widefield Search for Technosignatures with the Murchison Widefield Array. ApJ 972, 76; doi: 10.3847/1538-4357/ad6b11
Source : Breaking Science News