...while science gives us implements to use, science alone does not determine for what ends they will be employed. Radio is an amazing invention. Yet now that it is here, one suspects that Hitler never could have consolidated his totalitarian control over Germany without its use. One never can tell what hands will reach out to lay hold on scientific gifts, or to what employment they will be put. Ever the old barbarian emerges, destructively using the new civilization.

Anyone who has had actual contact with the making of the inventions that built the radio art knows that these inventions have been the product of experiment and work based on physical reasoning, rather than on the mathematicians' calculations and formulae. Precisely the opposite impression is obtained from many of our present day text books and publications.

During the war years I worked on the development of radar and other radio systems for the R.A.F. and, though gaining much in engineering experience and in understanding people, rapidly forgot most of the physics I had learned.

Ere long intelligence—transmitted without wires—will throb through the earth like a pulse through a living organism. The wonder is that, with the present state of knowledge and the experiences gained, no attempt is being made to disturb the electrostatic or magnetic condition of the earth, and transmit, if nothing else, intelligence.

I think that the event which, more than anything else, led me to the search for ways of making more powerful radio telescopes, was the recognition, in 1952, that the intense source in the constellation of Cygnus was a distant galaxy—1000 million light years away. This discovery showed that some galaxies were capable of producing radio emission about a million times more intense than that from our own Galaxy or the Andromeda nebula, and the mechanisms responsible were quite unknown. ... [T]he possibilities were so exciting even in 1952 that my colleagues and I set about the task of designing instruments capable of extending the observations to weaker and weaker sources, and of exploring their internal structure.

In 1945 J.A. Ratcliffe ... suggested that I [join his group at Cavendish Laboratory, Cambridge] to start an investigation of the radio emission from the Sun, which had recently been discovered accidentally with radar equipment. ... [B]oth Ratcliffe and Sir Lawrence Bragg, then Cavendish Professor, gave enormous support and encouragement to me. Bragg's own work on X-ray crystallography involved techniques very similar to those we were developing for "aperture synthesis", and he always showed a delighted interest in the way our work progressed.

In the new era, thought itself will be transmitted by radio.

It was shortly after midday on December 12, 1901, [in a hut on the cliffs at St. John's, Newfoundland] that I placed a single earphone to my ear and started listening. The receiver on the table before me was very crude—a few coils and condensers and a coherer—no valves [vacuum tubes], no amplifiers, not even a crystal. I was at last on the point of putting the correctness of all my beliefs to test. ... [The] answer came at 12:30. ... Suddenly, about half past twelve there sounded the sharp click of the “tapper” ... Unmistakably, the three sharp clicks corresponding to three dots sounded in my ear. “Can you hear anything, Mr. Kemp?” I asked, handing the telephone to my assistant. Kemp heard the same thing as I. ... I knew then that I had been absolutely right in my calculations. The electric waves which were being sent out from Poldhu [Cornwall, England] had travelled the Atlantic, serenely ignoring the curvature of the earth which so many doubters considered a fatal obstacle. ... I knew that the day on which I should be able to send full messages without wires or cables across the Atlantic was not far distant.

Professor Ayrton said that we were gradually coming within thinkable distance of the realization of a prophecy he had ventured to make four years before, of a time when, if a person wanted to call to a friend he knew not where, he would call in a very loud electromagnetic voice, heard by him who had the electromagnetic ear, silent to him who had it not. “Where are you? ” he would say. A small reply would come, “I am at the bottom of a coalmine, or crossing the Andes, or in the middle of the Atlantic.” Or, perhaps in spite of all the calling, no reply would come, and the person would then know that his friend was dead. Think of what this would mean ... a real communication from a distance based on true physical laws.
[His prophecy of cell phones, as a comment on Marconi's paper, ‘Syntonic Wireless Telegraphy’, read before the Society of Arts, 15 May 1901, about his early radio signal experiments.]

The key to SETI is to guess the type of communication that an alien society would use. The best guesses so far have been that they would use radio waves, and that they would choose a frequency based on 'universal' knowledge—for instance, the 1420 MHz hydrogen frequency. But these are assumptions formulated by the human brain. Who knows what sort of logic a superadvanced nonhuman life form might use? ... Just 150 years ago, an eyeblink in history, radio waves themselves were inconceivable, and we were thinking of lighting fires to signal the Martians.

This [the opening of the Vatican City radio station built by Marconi earlier in 1931] was a new demonstration of the harmony between science and religion that each fresh conquest of science ever more luminously confirms, so that one may say that those who speak of the incompatibility of science and religion either make science say that which it never said or make religion say that which it never taught.