The 1974 Nobel Prize for Physics was awarded to Sir Martin Ryle and Antony Hewish for their pioneering efforts to tune in to radio broadcasts from the stars. Their development and use of radio-based versions of telescopes has broadened our view of the universe by revealing information about stars in remarkable detail.
Sir Martin Ryle applied his expertise in developing airborne radar systems during the Second World War to intercepting radio transmissions that stars send out as they burn their fuel. Constructing a series of telescopes consisting of radio antennae attached to large receiver dishes allowed Ryle to detect characteristics of the Sun, such as its surrounding layer of hot gas, called the corona. Recognising more faint and distant stars was a daunting task, thought to be possible only by building dishes of impossible proportions, but Ryle’s finest technical achievement was showing that this could also be achieved by connecting a series of small telescopes all pointing in the same direction, a set-up known as aperture synthesis.
One of the most remarkable observations using radio astronomy was made in 1968, when Antony Hewish’s graduate student, Jocelyn Bell, spotted something in the skies that didn’t twinkle like a normal star. Spinning around rapidly this star shoots out a powerful lighthouse-like beam of radio waves, and as the beam repeatedly sweeps around it appears to blink every second when viewed from Earth. Hewish’s suggestion, later proved true, was that this so-called pulsar was the first sighting of the dense, burnt-out remains of a massive star that had been predicted to exist as far back as the 1930s. As these stars die spectacularly in a supernova explosion the extreme conditions fuse almost all the components of their atoms together to form a crushed ball of neutrons, hence their name neutron stars.
Ryle and Hewish’s Prize in Physics was the first to celebrate breakthroughs in astronomy. Ryle also had the additional honour of being the 100th individual to be awarded the Physics Prize since the first, Wilhelm Röntgen, in 1901.