On this day in 1905, Karl Guthe Jansky was born in Norman, Oklahoma. He only had a fairly short life—dying on Valentine’s Day, 14 February, 1950—but nevertheless he had an enormous impact on our understanding of our world and, more importantly, the entire universe surrounding it. Jansky was the first to understand that some of the static that affects analogue radio signals (even today) actually comes from distant stars, millions of miles away. So he started the all-important field of radio astronomy, which has widened our knowledge of space and the cosmos. In other words, he was a star discoverer.
Jansky studied physics at the University of Wisconsin and in 1928, after graduating, he started working at the Bell Telephone Laboratories in Holmdel, New Jersey. Bell Telephone Laboratories was working on the provision of transatlantic radio telephone services, and were intending to use short wave (around 10-20 metres wavelength) signals for this purpose—Jansky’s major task was to investigate and explore any sources of static that could interfere with short wave radio voice transmissions across the Atlantic Ocean. In order to find this out, he constructed a rotating antenna—nicknamed “Jansky’s merry-go-round”—to record signals from every direction.
After a few months of study with his merry-go-round, Jansky had discovered three main types of static: thunderstorms close by, thunderstorms far away, and a faint but constant mystery hiss, its origins unknown. After over a year of investigations into this perplexing mystery noise, he realised that it repeated every 23 hours and 56 minutes—a cyclical duration that is characteristic of fixed stars and other faraway objects in the distant universe, outside of our solar system. Thus Jansky deduced that the noise was actually originating in outer space, from the direction of the center of our galaxy.
Unsurprisingly, the great scientist wanted to experiment further, and proposed that Bell Telephone Laboratories build a 30-metre-wide dish antenna to receive the radio waves coming from the Milky Way. But Bell, now satisfied that this source of interference would not ruin their plans for transatlantic radio transmissions, were no longer interested. They simply assigned Jansky to another task, and he never worked on radio astronomy again.
In the late 1930s, other scientists—such as Grote Reber and John Kraus—started exploring the field of radio astronomy, and it has since played an essential role in helping us to discover stars in the universe. Thankfully, Karl Guthe Jansky is still credited as the “father of radio astronomy,” even though he was prevented from pursuing the full implications of his discoveries himself. Bell Labs even built a monument to commemorate him: a scale model of “Jansky’s merry-go-round” antenna.
Credit: ALAMY BBY82E
Caption: Karl Guthe Jansky with his directional radio aerial system.