From Olympic Fireworks to Cosmic Ones

by Nicholas Mee on September 3, 2012

Scientific Progress was the theme of the Paralympic Opening Ceremony.

On 29th August the Paralympic Games were opened in London in spectacular fashion. The Opening Ceremony took scientific progress as its theme, in particular the launch of the modern age by the publication of Newton’s masterpiece – The Principia. So amidst the fireworks we were shown clockwork planetary systems and cosmic vistas, there were plenty of apples and an inspirational narrative from the world’s most famous theoretical physicist Stephen Hawking. Hawking urged the audience to ‘Be Curious’ and ‘To look at the stars and not down at their feet’.

An Unlikely Superstar

Hawking has starred on a Pink Floyd album and even made appearances in The Simpsons. But he became a star of theoretical physics as a young researcher in the early 1970s when he addressed a meeting of British theorists at the Rutherford Appleton Laboratories near Oxford. Hawking had already been diagnosed with motor neurone disease and was using a wheelchair.

As he came to the conclusion of his talk, he broke the news of his momentous insight into fundamental physics. There was a stunned silence. The audience of experienced physicists were shocked. Finally, John Taylor, who was acting as chairman for this session of the meeting, stood up angrily saying “this is nonsense Stephen”, before rushing from the lecture theatre – apparently intending to write a paper to demolish Hawking’s idea. Needless to say, this is not the usual response to a fundamental physics seminar.

Black Holes Aren’t Completely Black!

Hawking’s outrageous proposal was that black holes are not completely black. Black holes were named by the American theorist John Wheeler because their gravitational attraction is so great that not even light can escape. It was believed that black holes must inexorably increase their mass as they suck up passing interstellar debris and nothing could ever come out of a black hole. But Hawking recognised that this analysis would not necessarily hold in a quantum theory of gravity.

Building on the work of Israeli physicist Jacob Bekenstein, Hawking had realised that it is possible to associate a temperature with a black hole. Any object with a temperature above absolute zero must emit radiation. Hawking’s result meant that this must also be the case for black holes, despite the preconceived ideas of the entire physics community. The radiation emitted by a black hole is now known as Hawking radiation. The temperature of a black hole with the mass of a star is incredibly low – about one ten millionth of a degree above absolute zero. This means that its output of Hawking radiation is so feeble that it could never be detected. But much smaller black holes, if they exist, would have a much higher temperature and would emit far more radiation.

Cosmic Fireworks

A spectacular image from the Opening Ceremony.

In 1974 Hawking speculated that if the Big Bang was quite turbulent there might have been pockets of material that were denser than average and these regions could have collapsed in the earliest moments of the universe to form mini black holes. These primordial black holes might have much less mass than the stellar mass black holes and it might therefore be possible to detect the Hawking radiation that they were emitting.

Such a black hole, with a mass of a mountain say, would lose mass as it emitted radiation, its temperature would therefore increase and so it would emit even more radiation. Finally the black hole would disappear in a blaze of gamma rays. Hawking suggested that it might be possible to witness the fireworks produced by the explosion of primordial black holes (as long as they weren’t too close). Astronomers are still on the look-out for these spectacular events.

It is worth remembering Hawking’s words from the opening ceremony: ‘The Paralympic Games is about transforming our perception of the world. We are all different. There is no such thing as a standard or run-of-the-mill human being but we share the same human spirit. What is important is that we have the ability to create. This creativity can take many forms, from physical achievement to theoretical physics. However difficult life may seem, there is always something you can do and succeed at.’

More Information

The video of the entire opening ceremony is available on YouTube at http://www.youtube.com/watch?v=Kd4FgGSY5BY

For more details on Hawking Radiation, see this fantastic short video from the BBC:  http://www.youtube.com/watch?v=S6srN4idq1E

And Finally…

Although it might seem a bit early, if you’re starting to think about Christmas Presents, we’ve got a great gift for the scientifically inclined (or you might just want to drop a hint or two…).

 

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