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Mystery radio signals that baffled astronomers for years came from the staff microwave

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A telescope started picking up the signals in 1998

Ian Waldie/Getty Images

Beginning in the late '90s, once or twice a year, astronomers operating the telescope at the Parkes Observatory in New South Wales, Australia would pick up mysterious radio signals. These signals were known as perytons, described in a recent report as "millisecond-duration transients of terrestrial origin." The researchers believed the perytons were linked to atmospheric activity such as lightning strikes, and they held this belief for around 17 years, until this year, when they installed a new receiver to monitor interference, The Guardian reports. The actual source of the perytons? A microwave.

The receiver detected signals at 2.4 GHz within 5 kilometers of the telescope, which the researchers realized were being created by staffers heating up their lunches in the Parkes Observatory kitchen. The interference only occurred when staffers opened the microwave door while it was still heating.

Digital interference in the time it takes to heat up leftovers

"If you set it to heat and pull it open to have a look, it generates interference," Simon Johnston, head of astrophysics at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) told The Guardian. The telescope also had to be pointed toward the microwave to pick up the signals.

When the telescope, known as The Dish, was built in 1961, Parkes was a quiet town and the observatory just outside it was largely isolated. But Johnston says digital interference has only gotten worse as time goes own.

To escape the digital noise, the astronomers looked for a more secluded area in which to build a new telescope, the Australian Square Kilometer Array Pathfinder (ASKAP). Johnston said they found the "quietest site on earth to do astronomy" in Western Australia — a place with no Wi-Fi, no radio signals, and no mobile phone coverage. That telescope is scheduled to be completed in 2016.

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