Cosmic Quest

Revolution Number Three: The Violent Universe

February 1942. The world was at war. But little did anyone realise that the violence of combat would alert us to violence on an altogether greater scale – the recognition that our Universe, far from being a calm haven, is a seething cauldron of unimagined energy and destruction.

It all began with the development of radar: echoes of radio waves that now allow air traffic controllers to track airplanes. In World War II, the technique was in its infancy; but it was being used – with some success – to home in on enemy bombers and ships.

One of the radar experts was 33-year-old Stanley Hey (pictured right) – a brilliant young physicist who had signed up for war service on the government’s scientific register. But there was always a worry that the enemy might ‘jam’ the Allies’ radar by transmitting on the same wavelength.

On 27 and 28 February 1942, Hey was alerted to powerful radar interference – during the hours of daylight – which covered the whole country. After analysing the data from several radar stations, Hey came to an inescapable conclusion.

The ‘jamming’ was not coming from a Nazi secret weapon, but from the Sun. He checked with the Royal Greenwich Observatory, and discovered that there was an enormous sunspot group generating huge magnetic eruptions – solar flares – that spew streams of energetic electrically-charged particles into the Solar System.

The first radio waves from space had been discovered over ten years earlier, by Bell Laboratories engineer Karl Jansky. The Bell Labs were keen on setting up a transatlantic communications system, and wanted Jansky to investigate sources of interference. He built a rotating radio antenna, which detected static from thunderstorms – and an unknown hiss that prevailed in the background. Delving deeper, Jansky discovered that it came from the Milky Way.

It could have been the start of radio astronomy. But the Bell Labs reckoned the static posed no threat to their communications system – and took Jansky off the job. He never returned to astronomy again. That’s why Stanley Hey deserves to be called the father of radio astronomy.

After the War, Hey joined the Royal Radar Establishment in Malvern, England. They had no radio astronomy research in progress, and so he took it upon himself to rectify the situation. As Hey recalls, a giant German Wurzburg radar dish (below) had been ‘acquired’ by the Establishment. Hey used it as the basis to build the first proper radio telescope in Britain, with a collecting dish 14 metres (45 feet) across. He quietly carried on his research out of the glare of publicity.

But his reputation had created waves amongst the young war scientists. Among them was Martin Ryle, a researcher at Cambridge who wanted to study radio waves from solar flares in more detail. And at Manchester, another budding radio astronomer, Bernard Lovell, borrowed Hey’s equipment to study radar echoes from meteors – another of Stanley Hey’s discoveries.

And the rest is history. Lovell created a sensation in detecting signals from the launcher that lofted Sputnik 1 into space – an ICBM that indicated Russia’s attempt to nuke the planet. Ryle and his team proved that our expanding Universe was born in a Big Bang, now dated to 13.7 billion years ago. And Ryle’s young research student, Jocelyn Bell, would go on to discover pulsars – the cadavers of stars that have exploded as supernovae.

The advent of radio astronomy opened new windows onto the cosmos. It ushered in new technologies - so that astronomers are no longer limited to simply looking at the sky.

Satellites high above Earth’s blocking atmosphere finally have the ability to tune into the cosmos at a whole range of wavelengths – from hugely energetic gamma rays to the lowest frequency radio waves.

And this recent cornucopia of data on the cosmos has told us – in no uncertain terms – that we live in a violent universe. The safe, predictable, stars and planets of our ancestry have been replaced by wild worlds. Black holes, erupting galaxies (like Centaurus A, pictured left), wayward planets and exploding stars are all out there on the cosmic stage.

However, astronomers have evidence that - despite all this disruption – there could be life elsewhere.

We have now discovered hundreds of planets circling distant suns. Many may boast life – even if it is only green slime. But surely more advanced lifeforms must have evolved?

Cosmic Conversation: Revolution Number Four?

Let me predict the next revolution in astronomy. It will be the day when we make contact with intelligent extraterrestrial life.

And who knows where that will lead us?

For more information

Listen to Heather Couper's 30-part radio series on the history of astronomy, Cosmic Quest, on BBC Radio 4.

The programmes air at 3:45 pm BST (14:45 GMT) every weekday from 26 May for six weeks, with a one-hour Omnibus edition on Fridays at 9pm BST (20:00 GMT).

Click on:
http://www.bbc.co.uk/radio4/
and either follow links to Listen Live for the real-time broadcast, or Listen Again to hear the programmes later.

 
BBC webpage on Cosmic Quest
http://www.bbc.co.uk:80/radio4/science/cosmology/