radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...

, perytons are short man-made radio signals of a few milliseconds resembling fast radio bursts (FRB). A peryton differs from radio frequency interference by the fact that it is a pulse of several to tens of millisecond duration which sweeps down in frequency. They are further verified by the fact that they occur at the same time in many beams, indicating that they come from Earth, whereas FRBs occur in only one or two of the beams, indicating that they are of galactic origin. The first signal occurred in 2001 but was not discovered until 2007. First detected at the

Parkes Observatory Parkes Observatory is a radio astronomy observatory, located north of the town of Parkes, New South Wales, Australia. It hosts Murriyang, the 64 m CSIRO Parkes Radio Telescope also known as "The Dish", along with two smaller radio telescopes. T ...

, data gathered by the telescope also suggested the source was local. The signals were found to be caused by premature opening of a

microwave oven A microwave oven, or simply microwave, is an electric oven that heats and cooks food by exposing it to electromagnetic radiation in the microwave frequency range. This induces Dipole#Molecular dipoles, polar molecules in the food to rotate and ...

door nearby.

Naming

Due to the unclear origin of the detections at first, the radio signals were named after the peryton, a fictional winged stag that casts the shadow of a man. This interprets into "strangeness made by man". This name was chosen for these signals because they are man-made but have characteristics that mimic the natural phenomenon of FRBs. The name was coined by Sarah Burke-Spolaor et al. in 2011.

Detection

Perytons were observed at the Parkes Observatory and Bleien Radio Observatory. After the discovery of the first FRB in 2007, Dr. Burke searched through old telescope data looking for similar signals. She found what she was looking for, with a small difference. The 16 signals that she found seemed to fill the entire patch of the sky visible to the telescope. The lack of directionality in the new signals led Burke to the considerations that the signals were man-made and of earth. Between 1998 and 2015, old data showed 46 perytons that were identified at the Parkes Observatory. On June 23, 1998, 16 perytons were detected at that same location within 7 minutes. In January 2015, 3 perytons were detected at the Parkes Observatory. As of 2015, 25 perytons had been the subject of scientific publications.

Origin hypotheses

These signals mimicked some aspects of FRBs that appeared to be coming from outside the

Milky Way galaxy The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galaxy, which are ...

, but the possibility of their having an astronomical origin was soon excluded. To track activities near the telescope, the Commonwealth Scientific and Industrial Research Organization (CSIRO) installed a radio frequency interference (RFI) monitor at the Parkes site in December 2014. This form of monitoring became more common as radio-emitting devices became more prevalent on radio telescope sites, including mobile phones, Wi-Fi, and digital televisions. Important information was disclosed by the RFI monitor data, which had not been accessible for earlier peryton discoveries. Each peryton event was accompanied by a period of radio emission at a frequency of 2.5 GHz that was outside the telescope's field of view. These spikes were probably related to the perytons. Hypothesized potential sources of perytons included: * Signals from aircraft * Flashes in the

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays ...

Lightning Lightning is a natural phenomenon consisting of electrostatic discharges occurring through the atmosphere between two electrically charged regions. One or both regions are within the atmosphere, with the second region sometimes occurring on ...

Solar flare A solar flare is a relatively intense, localized emission of electromagnetic radiation in the Sun's atmosphere. Flares occur in active regions and are often, but not always, accompanied by coronal mass ejections, solar particle events, and ot ...

s *

Terrestrial gamma-ray flash A terrestrial gamma-ray flash (TGF), also known as dark lightning, is a burst of gamma rays produced in Earth's atmosphere. TGFs have been recorded to last 0.2 to 3.5 milliseconds, and have energies of up to 20 million electronvolts. It is spe ...

es * Narrow bipolar pulse (electrical discharges between clouds at high altitude with a capacity of several hundred

gigawatts The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named in honor o ...

)

Identification of origin

In 2015, perytons were found to be the result of premature opening of microwave oven doors at the Parkes Observatory. On March 17, 2015, three perytons were produced by experimentation by microwaving ceramic mugs filled with water and opening the door before the microwave had stopped operating. The microwave oven releases a frequency-swept radio pulse that mimics an FRB as the

magnetron The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave oven, microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of ...

turns off. Two Matsushita microwave ovens were deemed responsible for most of the perytons. Both were functional and over 27 years old. Perytons were found to be produced about 50% of the times that the microwave door was opened before the timer expired.

References

External links

What is a peryton?
at Physics