USAF first discovered pulsar in Crab Nebula

In the Birthday Honours List, the Queen made Jocelyn Bell, the astrophysicist a Dame of the British Empire. Lord Patel posted the fascinating story of her discovery of the first pulsar (now called PSR B1919+21 ) and it's publication in Nature in 1968 ((A. Hewish et al. Nature 217, 709-713; 1968). Her supervisor Antony Hewish was later awarded a Nobel prize for the discovery, but she was not. A continung source of bitter personal controversy.

Pulsars are most likely the remnants or neutron stars resulting from the collapse of massive stars as predicted by Robert Oppenheimer and Fritz Zwicky (who remarkably lived next door to Lenin in Zurich) in the 1930s.

The central part of a pulsar consists of a neutron star. They are accompanied by magnetic fields of immense strength - many millions of times stronger than those ever produced on Earth. The neutron star is surrounded by an electrically-conducting gas or plasma. Each pulsar rotates and emits beams of radiation in the Universe, in the way light escapes from a lighthouse beacon which strike the Earth periodically with high precision - in the case of PSR B1919+21 30 times a second.

Now Nature have published a report that their existence had been previously discovered bya US Air Force staff sergeant of 13th Missile Warning Squadron (MWS), Charles Schisler then 41, in 1967, operating a workstation on the Ballistic Missile Early Warning System,(BMEWS) at the 11,000 acre Clear Air Force Station in Alaska (click on pic to enlarge) on a massive set of military radars that looked some 4,800 km across Siberia for incoming warheads. (On 15th December 2000 after nearly 40 years of operation, the last of the original BMEWS radars ceased transmitting, and the Solid-State Phased-Array Radar System SSPARS began 24-hour operations. It now operates with radar units at Thule Air Base, Greenland, and Fylingdales-Moor, United Kingdom, which comprise the current Ballistic Missile Early Warning System.

He had noticed noticed a faint signal on his radar , all summer it showed up. Then he noticed the unexplained blip appeared 4 minutes earlier than the day before. As an ex- navigator of B - 47's he new that stars rise 4 minutes earlier each night as the seasonal rotation of the Earth shortened the day's length in the Northern hemisphere.

He calculated the radio source's approximate position in the sky and took a weekend trip 125 miles to the University of Alaska at Fairbanks,an astronomy professor directed him to find a catalog of celestial radio sources -- "General Catalog of Discrete Radio sources" (Howard and Maran ApJ Supp. 10, 1 1965 . He had not known that celestial radio sources had been documented. In this way, Charles determined that he had observed a radio source Taurus A -- the Crab Nebula some 6,300 light years from Earth. At the centre of the Crab, a supernova remnant, we now know, sits a bright (well, noisy) pulsar. The nebula was first identified in July 4, 1054 A.D. by Chinese astronomers as a new or "guest star," and is about four times brighter than Venus but wasn't named until 1844.


Schisler returned to Clear with the coordinates of other likely radio sources and began a meticulous log of any "sightings" .By his own count, he spotted about a dozen sources. "My commanders didn't know what the hell I was doing," he recalls. (for more technical detail of the site equipment and it's uses see website - Montreal 2007: 40 Years of Pulsars
Schisler was not the only one to "pre-discover" a pulsar, though, according to Jocelyn Bell .

"There are actually a lot of stories," she says. A woman visiting the observatory at the University of Chicago, Illinois, in 1950 identified a regularly pulsating source of visible light in the Crab Nebula. An astronomer at the university, dismissed the claim, explaining that all stars seem to flicker - which is true as the earth's atmosphere does causes the twinkling of a star at optical wavelengths.

She also claims another radio astronomer, who may be encouraged, when plied with liquor to confess to having dismissed observations of a pulsating source as the result of faulty equipment. This story is not in anyway connected to Sir Bernard Lovell and the Jodrell bank telescope who discovered a double pulsar in 2003. But they are proud of the fact that their microwave oven in the staff canteen is kept in a Faraday cage to stop radiation escaping. Staff relate a possibly apocryphal-sounding anecdote from the Search for Extraterrestrial Intelligence, when a promising signal turned out be a technician warming his lunch at the Arecibo Observatory in Puerto Rico.
If you visit Jodrell bank - highly recommended if only for the immense and world famous Arboretum, you will be required to switch off your mobile telephone.

As Rene Briton remarks at the Montreal website "Once again, it shows how subtle is the nature of discoveries: Mr. Schisler could have let this little "annoying" signal go and not bother about it but instead he carefully recorded details of what he observed. - and "wonder(s) how many such discoveries will remain unknown forever... "

On the other hand the original discovery of gamma ray bursts GRB's (extra galactic and the most luminous events known in the universe since the Big Bang). They are flashes of gamma rays, coming from seemingly random places in the sky and at random times. The first observations were made with the Vela rockets sent up to detect Soviet weapon tests after the test ban treaty in 1963 - but they did identify the Israeli backed South African tests in the so called Vela incident .

Whilst their detection of the GRB's was classified for many years the results were eventually published in 1973 - Observations of Gamma-Ray Bursts of Cosmic Origin:
Klebesadel, Ray W.; Strong, Ian B.; Olson, Roy A.: Astrophysical Journal, vol. 182, p.L85 06/1973

Who knows what discoveries are languishing in sealed files today?