The first scientific experiment at Jodrell Bank took place 75 years ago; from an army radar trailer, on a damp and icy Friday afternoon on the 14th December 1945.
Although crude by today’s standards, it is the foundation on which the ground-breaking research at Jodrell Bank has been built. However, the story is not as simple as it sounds. The outcome of this first experiment was something of a happy accident; a coincidence of timing and human error.
Above: Setting up the first radar experiment at the University of Manchester’s Experimental Botany Grounds Jodrell Bank, 14th December 1945. Copyright University of Manchester
In 1945 Bernard Lovell was a physicist at the University of Manchester and he was looking for cosmic ray showers – high-energy particles entering the earth’s atmosphere. Whilst developing wartime radar systems Lovell had speculated about this new technology; if radar could be used to detect aircraft at night, could it be used to detect other invisible things, like the cosmic rays he had been studying before the war?
When the war ended Lovell acquired some surplus equipment from the army and drove it out to the University of Manchester’s experimental botany grounds at Jodrell Bank in Cheshire. It was isolated with no electricity, but this was perfect for his purposes. No electricity meant no interference to confuse his readings.
Above: Jodrell Bank farmland, c.1945. Copyright University of Manchester
But he had more terrestrial issues to deal with first. His trailers got stuck in the mud, the diesel generator kept icing up, and it was only with the help of the two friendly gardeners and a local farmer that Lovell got the equipment working at all. Late in the day on the 14th December he switched on the transmitter and the receiver and directed the aerial to the sky. It was a success! But, as he describes in his oral history interview for Web of Stories…
‘I switched on in mid-December in a most extraordinary coincidence. I anxiously looked at the cathode ray tube. It was free of this interference, but full of transient echoes, and I thought, marvellous. These must be the radar echoes from huge cosmic ray air showers. Then I had a few moments of doubt and I thought, no it can’t be. There can’t be as many huge air showers as that…’
The coincidence he refers to is the date: 14th December. Lovell knew nothing of astronomy at this time, so was not aware that he did his first observations at the peak of the annual Geminids meteor shower. The large number of transient echoes he detected were in fact from meteor trails.
|Meteor. Source: Alan Newman (CC BY-NC 2.0)||Artist’s conception of a cosmic ray shower. Source: Chantelauze / Staffi / Bret (CC BY-NC 4.0)|
What followed were months of recalculation, adjustment and correspondence with fellow scientists as Lovell tried to make sense of his results. It turned out that he hadn’t considered the effects of damping in his calculations (i.e., that the electrons from cosmic ray showers would collide with other atmospheric particles, decreasing the amount of energy scattered back to earth); a critical oversight that meant it would have been almost impossible for his equipment to detect energy from cosmic ray showers. But he had found something more interesting; Lovell quickly realised the potential of meteor research and was drawn into the world of astronomy.
History shows that many of the great leaps forward in science have come about through mistake and serendipity: Newton’s apple, and Fleming’s discovery of penicillin in some unwashed petri dishes. If Lovell had arrived at Jodrell Bank in January he would have missed the spectacular echoes from the Geminids, or if he had checked his calculations he may never have attempted the observations in the first place. The happy accident of Lovell’s first experiment is just one of the many twists and turns in the story of Jodrell Bank and we are uncovering many more of these stories and telling them as part of the First Light at Jodrell Bank project.