There is a saying in science that it is never aliens... until it is. A great many natural phenomena can generate electromagnetic radiation.
On Wed, Sep 8, 2021 at 7:01 PM Larrywrote:
I am enjoying a great sci fi book called Omega from Jack MxDevitt, which has bad things coming from the galactic center...but here is something new in reality...
Astronomers have detected a strange, repeating radio signal near the center of the Milky Way, and it's unlike any other energy signature ever studied.
According to a new paper accepted for publication in The Astrophysical Journal and posted on the preprint server arXiv, the energy source is extremely finicky, appearing bright in the radio spectrum for weeks at a time and then completely vanishing within a day. This behavior doesn't quite fit the profile of any known type of celestial body, the researchers wrote in their study, and thus may represent "a new class of objects being discovered through radio imaging."
The radio source — known as ASKAP J173608.2−321635 — was detected with the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope, situated in the remote Australian outback. In an ASKAP survey taken between April 2019 and August 2020, the strange signal appeared 13 times, never lasting in the sky for more than a few weeks, the researchers wrote. This radio source is highly variable, appearing and disappearing with no predictable schedule, and doesn't seem to appear in any other radio telescope data prior to the ASKAP survey.
When the researchers tried to match the energy source with observations from other telescopes — including the Chandra X-ray Observatory and the Neil Gehrels SwiftObservatory, as well as the Visible and Infrared Survey Telescope for Astronomy in Chile, which can pick up near-infrared wavelengths — the signal disappeared entirely. With no apparent emissions in any other part of theelectromagnetic spectrum, ASKAP J173608.2−321635 is a radio ghost that seems to defy explanation.
Prior surveys have detected low-mass stars that periodically flare up with radio energy, but those flaring stars typically have X-ray counterparts, the researchers wrote. That makes a stellar source unlikely here