Several years ago (2010) I met an astronomer from Jodrell Banks radio telescope (one of the first big ones operated by the UK) and she told me the story of a signal being detected, which was thought to be from some intelligent alien source in the cosmos.
The signal was detected at 10.30 am every time. After some investigation, it turned out to be the microwave oven used to heat the muffins for morning tea. It was from an intelligent source after all, but not from space. Her anecdote sounds very similar to what was proven to have been the source of some anomalous signals at the Parkes radio telescope in Australia.
Perytons at Parkes
According to Simon Johnston, head of astrophysics at CSIRO, in 1998 the Parkes radio telescope began detecting some fast radio bursts and related signals named perytons once or twice a year. It was theorised that these may have been signals from another galaxy, or emissions from neutron stars becoming black holes, or just interference from lightning strikes. But in 2015 it was determined that perytons were detected by the Parkes telescope when staff opened the door of the microwave oven at the facility to heat their lunch.1
“ … 1 January  they installed a new receiver which monitored interference, and detected strong signals at 2.4 GHz, the signature of a microwave oven.”1
Immediate testing of the facility microwave oven did not show up any perytons. Until, that is, they opened the oven door before it had finished heating. “If you set it to heat and pull it open to have a look, it generates interference,” Johnston said.1
Problem solved! No signal there from ‘little green men’ either!
Prior to the installation of the new microwave oven, the old oven operated at 1.4 GHz and was the source of those spurious signals for a long time. 1.4 GHz is very close to the frequency of the 21 cm (8 in) wavelength signal astronomers very frequently look for as it comes from hydrogen atoms, which are common in space.
The Wow! signal
On 15 August 1977, radio astronomers using the Big Ear radio telescope at Ohio State University picked up a powerful signal from space. Some believed it was our first interception of an alien broadcast.
The signal—known as the “Wow! signal” after a note scribbled by astronomer Jerry Ehman, who detected it—came through at 1.420 GHz, corresponding to a wavelength of 21 cm (8 in). Searchers for extra-terrestrial transmissions have long considered it an auspicious place to look, as it is one of the main frequencies characteristic of hydrogen.2
This was a one-off and they never heard anything like it again. In this case it was determined that it did come from space and not some pesky microwave device. So ET was suspected.3 Now, astronomy Professor Antonio Paris thinks the signal might have come from one or more passing comets. He suspects two comets, called 266P/Christensen and P/2008 Y2 (Gibbs), which were not known in 1977. Others, however, are not so convinced.
Therefore to test his idea, Prof. Paris proposed to search the same region of space that Big Ear was pointing at when these comets return. They will transit the region on 25 January 2017, and on 7 January 2018, respectively. An analysis of the hydrogen signal of the comets should reveal if he is correct (I suspect he is).
These stories are only significant because of the evolutionary belief system, which says that if life evolved on earth it must also have evolved elsewhere in the cosmos. Mankind now has been searching for 50 years, fruitlessly, for a source of intelligence from the cosmos. But God the Creator has already revealed that He is the Intelligent Source from which life came, when He created Adam from the dust of the ground.
- M. Tan, Microwave oven to blame for mystery signal that left astronomers stumped, theguardian.com, May 5, 2015.
- Famous Wow! signal might have been from comets, not aliens, New Scientist, January 11, 2016.
- Forum: Wow! Was that ET?, New Scientist, August 9, 1997.
Comment added April 9, 2016
I’ve been thinking more about that Wow! signal. I had previously thought that the string of characters represented an ASCII representation of a series of pulses. However, after reading the Wikipedia article, I understand it is just an arbitrary encoding of amplitude to alphanumeric character that enabled a three-dimensional signal to be displayed easily on the 2-dimensional devices that were available at the time. What they actually detected was just a large signal at (approximately) the hydrogen line. Could have been caused by all sorts of things. At best what they seem to have been able to conclude is that it did not originate on Earth — but, perhaps, this is also not definitive.
Comment added June 10, 2017
The comets, P/2008 Y2(Gibbs) and 266/P Christensen appeared again in the night sky from November 2016 through February of 2017.
The team reports that radio signals from 266/P Christensen matched those from the Wow! signal 40 years ago. To verify their results, they tested readings from three other comets, as well, and found similar results. The researchers acknowledge that they cannot say with certainty that the Wow! signal was generated by 266/P Christensen, but they can say with relative assurance that it was generated by a comet.
Read more at: https://phys.org/news/2017-06-wow-mystery-space.html#jCp