It is not uncommon for radio telescopes to receive unexplained radio waves. While such signals could possibly come from regions in outer space, the source of a certain mysterious radio signal has been found to come from somewhere right at home.

The mysterious signals, named perytons, are similar to the noted dispersion of astrophysical pulses across cold plasma, which are known as an FRB or "fast radio burst." The origin of FRBs is unexplained, but the origin of perytons has now been traced to, surprisingly, a household appliance.

In a report, Emily Petroff of the Parkes Observatory in Australia wrote that the physical origin of perytons had been a mystery, with strong, out-of-band emissions recording 2.3 GHz to 2.5 GHz being connected with perytons.

"Subsequent tests revealed that a peryton can be generated at 1.4 GHz when a microwave oven door is opened prematurely and the telescope is at an appropriate relative angle," Petroff and her team revealed.

Petroff's statements meant that, if a person would open the door of a microwave before the appliance finished running, the microwave will release a short but very strong radio signal. If a radio telescope was angled facing the direction of the microwave, the FRB-like signal will be picked up.

One major difference between FRBs and perytons, Petroff noted, is that perytons appear to be originating from near us over a wide field of view, while FRBs originate from one source. Petroff also noted that perytons are found mostly during office hours on weekdays, which further adds to the credibility of the explanation that the mysterious perytons were in fact only being caused by microwaves.

To trace the origins of perytons, Petroff's team put up a real-time monitor for radio interference at the observatory. In January, the monitor recorded three radio signals that were simultaneous with instances when the telescope picked up perytons.

Because the signals occurred within the frequency range being released by microwave ovens, Petroff's team decided to try replicating the phenomenon using the microwaves in the observatory. Sure enough, the researchers found that they could create perytons by simply opening the door of microwaves while the oven was still running.

According to Petroff, the two microwave ovens that were producing most of the perytons that were observed were both made by National/Matsushita and are over 27 years old but still reliably operate. The research points to the magnetrons of the ovens as the origins of the perytons and that perytons are not unusual faults but are instead inherent to certain oven types.

Photo: Michael Coté | Flickr

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