The 4% Universe

The 4% Universe: Dark matter, dark energy and the race to discover the rest of reality by Richard Panek

Times, 12 February 2011

For Galileo seeing was believing. When in 1609 he learnt of the Dutch invention of the telescope, he quickly constructed his own. With no reason to think there was anything to find, he searched the night sky and found that there was far more to the universe than meets the naked eye. He saw that the Moon had mountains, the Sun had spots and he observed the phases of Venus. With the discovery of Jupiter’s moons, Galileo found hard evidence that not all heavenly bodies revolved around the Earth. In March 1610 he published, The Starry Messenger, his report of what he had seen. All 500 copies were sold within a week.

Four centuries later Galileo’s successors know that they cannot see, even using their dazzlingly variety of modern telescopes, an astonishing 96 percent of the universe. The tiny fraction that is visible to their fine-tuned instruments is the stuff that we and all the countless planets, stars and galaxies are made from. Get rid of us and of everything else we’ve ever thought of as the universe, and very little would change. ‘We’re just a bit of pollution,’ one cosmologist says. We maybe irrelevant, but the rest of reality has been dubbed ‘dark’ and for the American science writer Richard Panek it ‘could go down in history as the ultimate semantic surrender’. For this is not ‘dark’ as in distant or invisible, but ‘dark’ as in unknown - for now at least.

Yet what is known is that almost a quarter of what can’t be seen is something called dark matter. Although its very nature is a mystery, its presence is discernible through its gravitational effect on the movement of galaxies. Without dark matter the astronomical data doesn’t make sense.

From a derelict iron mine in Minnesota to mountaintop observatories, at a pace that would shame many a thriller writer, Panek tells the story of the quest to unlock the secrets of dark matter and the particles that make it up. These weakly interacting massive particles, or WIMPs, have proven so elusive that the possibility that two were detected in November 2009 caused great excitement.

Dark matter is less than half the tale Panek wants to tell. For three quarters of the unknown universe consists of an even stranger substance called dark energy. Its existence was inferred, once again, from the circumstantial evidence gathered by astronomers measuring what could be seen. They didn’t need Sherlock Holmes to remind them that after eliminating the impossible, whatever remains, no matter how improbable, is the truth.

In the late 1990s two rival teams set out to collect data on distant supernovae in an attempt to determine the rate at which the universe was expanding. It was assumed that the pull of gravity would act as a break on the pace of expansion. To their disbelief they found that space-time was being pushed apart faster than ever before. Something was overwhelming the force of gravity to drive the expansion. Dark energy was winning the cosmic tug-of-war.

With a future Nobel prize at stake, disputes and arguments over who did what and when were inevitable. Parek provides a behind-the-scenes glimpse of science in the raw as alliances are forged and friendships strained. There is a new universe to explore and the latest experiments reveal it is 13.75 billion years old and made up of 72.8 per cent dark energy, 22.7 per cent dark matter and 4.5 per cent ordinary matter. These numbers are ‘an exquisitely precise accounting of the depths of our ignorance,’ says Panek. ‘It’s 1610 all over again.’

Pathfinders

Arabic Heights

Pathfinders: The Golden Age of Arabic Science by Jim Al-Khalili

The Times, 18 September 2010

Stockholm, December 1979. Ten men wait to receive their Nobel prizes from the King of Sweden. Nine are wearing white tie and tails. Abdus Salam, a devout Muslim, stands out in a turban and traditional Punjabi clothes. The Pakistani physicist is being honoured for his part in formulating the electroweak theory that unites electromagnetism and the weak nuclear force. ‘There is no doubt in my mind that his work places him as the greatest physicist of the Islamic world for a thousand years,’ says Jim Al-Khalili, Iraqi-born physicist-cum-writer.

For many non-Muslims, the term ‘Islam’ evokes a ‘negative stereotype that contrasts with our Western, secular, rational, tolerant and enlightened society’, says Al-Khalili. This captivating book is his timely reminder of the debt owed by the West to the intellectual achievements of Arab, Persian and Muslim scholars, a thousand years before Salam got his Nobel prize, when the roles were reversed.

Al-Khalili has long wanted to tell the tale of the ‘golden age of Arabic science’ that began in the late 8th century and lasted for more than 500 years. Since there is no such thing as ‘Jewish science’ or ‘Christian science’, Al-Khalili explains that by ‘Arabic science’ he means the remarkable body of work produced in Arabic, the lingua franca of science and much else as Europe slumbered through its Dark Ages.

The Koran was the first book written in Arabic, and much effort was spent studying and interpreting it. The wealth and power of the growing Islamic empire made it possible for the Abbasid caliphs to promote an ever-expanding sphere of academic inquiry that had been lost since the glory days of Greek Alexandria. Advances in maths, astronomy, physics, chemistry, medicine and the flourishing of philosophy that took place, first in Baghdad and then across the Islamic world, all have their origins in what historians call the translation movement.

Thanks to the practical benefits it brought in finance, agriculture, engineering and health, the translation movement was a 200-year process during which much of the wisdom of the Greeks, Persians and Indians was translated into Arabic. These translations helped produce a culture of scholarship that became self-sustaining and formed part of a wider quest for knowledge that evolved into a new tradition of intellectual exploration that sparked the beginning of an age of scientific progress. A 9th-century caliph of Baghdad created the House of Wisdom, a centre of learning that some say was home to 400,000 books – at a time when the best European libraries held no more than a few dozen.

In 711, Muslims crossed into Spain and so began almost eight centuries of Islamic influence in Andalusia. Just as Baghdad had been the epicentre of the translation movement from Greek into Arabic, so cities like Córdoba and Toledo became the centres of translation of the great Arabic texts into Latin. One of the first scholars to study these was Gerbert d’Aurillac, a 10th-century French monk. He would later become the first Christian scholar to carry Arabic learning across the Pyrenees. It seems fitting that the man who would later become Pope Sylvester II introduced Christian Europe to the science of the Islamic empire.

Al-Khalili argues that the scientific revolution could not have taken place without the advances of the medieval Islamic world. Ibn al-Haytham dominated the field of optics long before Newton and used the scientific method 600 years before Francis Bacon even thought about it. Abdus Salam, who died in 1996, named some of the giants of Arabic science in his Nobel lecture: al-Biruni, al-Razi, Ibn Sina, Jabir, and al-Khwarizmi. If you want to know what these men did, read this fascinating book and let Al-Khalili tell you their stories.

‘We should not be ashamed to recognise truth and assimilate it, from whatever quarter it may reach us, even though it may come from earlier generations and foreign peoples,’ wrote Ya’qub ibn Ishaq al-Kindi, one of the great polymaths of the ‘golden age’. ‘For the seeker after truth there is nothing of more value than truth itself; it never cheapens or debases the seeker, but ennobles and elevates him.’