Interference is Everywhere
Interference (unwanted signal or noise) is everywhere, and isn’t always what you predict!
Any scientific analysis has to take into account any possible sources of interference. From fluorescence in X-ray diffraction (XRD) to magnets in the Scanning Electron Microscope (SEM), a good scientist must always be aware of the factors that may affect, bias or obscure their results.
Unfortunately those sources of interference aren’t always easy to pinpoint as was shown recently at the Parkes Observatory earlier this year. Parkes Observatory, in central west NSW, houses one of the radio telescopes comprising CSIRO’s Australia Telescope National Facility and has contributed significantly to global astronomical discoveries.
The Parkes radio telescope has the capacity to pick up a range of radio signals from terrestrial and non-terrestrial sources. The observatory has for some time been picking up mysterious radio signals known as ‘perytons’, named after a mythical winged stag and similar in nature to the extraterrestrial FRBs (fast radio bursts) but determined to be terrestrial (from earth) in origin.
After much confusion, the mystery was solved early this year when it was discovered that the perytons were the result of the observatory’s lunchroom microwave ovens releasing brief pulses of radio waves when the doors was opened too quickly (interesting science can give you quite an appetite!). The two microwave ovens responsible were both over 27 years old, and were found to be the origin of perytons for the last 17 years! It appears the radio bursts only occurred when the microwave door was opened prior to the microwave (resonator) turning off.
While slightly embarrassing, this did lead to the discovery that perytons are distinguishable from FRBs, and that the first known FRB, which was also the first FRB detected by the Parkes telescope could not be attributed to the microwave ovens.
Even in the search for interference, science marches on (after lunch of course).