Mystery SETI Signal Set Rules of Engagement

[dropcap]In[/dropcap] the Fall of 967, a small team of radio astronomers came face-to-face with a profound mystery that they didn’t want to be true.

At one point they half-seriously thought about destroying the data and staying stone silent. That’s because announcing it to the world could open a Pandora’s box for science, and derail at least one astronomer’s PhD thesis.

A small group of radio astronomers in the United Kingdom had stumbled upon clock-precision radio pulses coming from deep space. The signal was unlike anything ever seen before or even predicted in astronomy. In the absence of a natural explanation, the researchers pondered, for three long weeks, whether this was really a “hello” from an extraterrestrial civilization.

The team faced a cultural black hole with regard to the public response. How do you verify the signal? How do you announce it to the world? Do you send a reply to the stars, or is that too dangerous?

As is the case in our compulsive universe, nature was cleverer than imagined. This story of mistaken identity, as recently researched by Alan Penny of the University of St. Andrews, set the stage for preparing a SETI protocol for how to announce the discovery of the real deal sometime in the future.

Little Green Men

In July 967, a novel long-wavelength radio telescope, the largest of its time, began operations at the Mullard Radio Astronomy Observatory in Lord’s Bridge, Cambridgeshire, U.K.

Antony Hewish built the array to study radio emissions from quasars, a very distant, energetic and utterly mysterious newly discovered class of object (today we know they are the black hole powered cores of active galaxies). Graduate student Jocelyn Bell took home a 98-foot long paper strip chart of the telescope’s observations (this was a time before microcomputers and wide use of digital data processing and storage by astronomers).

While marking up the chart in her attic, she noticed a peculiar source that was flickering like a police car strobe light. As any good scientist would do, she checked for instrument noise, malfunction or man made clutter. (In 1963 the all-sky glow of the cosmic microwave background was first suspected to be radio contamination from pigeon droppings in a radio communications antenna.)

Bell realized that the source moved with the Earth’s rotation. The source really is in the sky and somewhere out there in the galaxy!

The telescope’s builder, Hewish, was intrigued and installed a faster strip recorder. The ghostly source reappeared in On Nov. 28 and the astronomers recorded pulses that lasted a fraction of a second but recurred precisely every 1.3 seconds. The eye-opener was that the pulses were so short in duration that they had be coming from something smaller than a few thousand miles across. This might place the source on an Earth-sized planet rather than a star!

What’s more, the unusually narrow frequency of the signal mimicked the signature of man made radar transmissions.

In the absence of a physical explanation, the astronomers toyed with the possibility that the signal could be coming from an alien civiliz