Africa could host the world's most powerful telescope

Sitting in a white prefab hut, Lindsay Magnus punches a code into a computer beneath bands of red, green and blue representing the Centaurus A galaxy. Beyond the window, seven giant dishes turn in unison, throwing shadows across the gravel. Their target lies millions of light years away in the cosmos. Magnus and his colleagues are aiming to build the world's biggest telescope. 

It will cost £1.3bn and consist of thousands of dishes with a total surface area of one square kilometre. It will generate enough raw data to fill 15m 64 GB iPods every day, requiring a supercomputer 1,000 times faster than currently exists. It will peer back to a time before the first stars and galaxies formed and offer our best chance yet of detecting alien intelligence. And there is a strong chance the telescope will be African. Bids will be submitted on Thursday to host the Square Kilometre Array (SKA), an instrument that turns radio waves into pictures of galaxies, exploding stars and other space phenomena.

The contest pitches South Africa (in partnership with eight other African countries) against Australia and New Zealand. Both contenders offer vast tracts of land with tiny populations – vital to avoid interference from mobile phones and other electronics. Both are also in the southern hemisphere, which offers a better perspective on the centre of our galaxy but which has been relatively neglected to date. An old joke has it: "God put all the astronomers in the northern hemisphere and all the interesting objects in the southern." But Africa would also have political purchase. A continent often written off as broken and doomed, and a backwater of scientific research is on the verge of landing one of the most important astronomical projects of the early 21st century.

Much was said about last year's football World Cup as a blow to "Afro-pessimism." The SKA could be a galvanising moment for its intellectual capital, self-confidence and prestige around the world. "I work in a world class field and now I can do it at home, I don't have to go overseas," said Magnus, commissioning scientist at the Karoo Array Telescope (KAT-7), a prototype of the SKA. "If it comes to Africa, conversations will happen that never could have happened. "If you were to think about the way to impact people here with science, there's no better way. Children already know there's something big going on – it's broadening their horizons. It's very different from the daily toll of war, famine and poverty." KAT-7 is an array of seven 16-metre-tall dishes undergoing tests in the Karoo desert.

Staff charter a weekly flight from Cape Town to the Northern Cape village of Carnarvon, then drive for an hour into a wilderness where only sheep, springboks and hardy farmers venture. Mobile phone reception soon disappears, which is just the way the researchers like it. This is a quarantined zone where anything that emits radio frequency interference (RFI) is like an infectious disease. Internet connections are by fibre optic cables only. "Wifi is a curse word round here," one scientist observed. Such is the dishes' sensitivity that their "cold" receivers are cryogenically cooled to about 70 kelvin (-203C) to reduce "noise". 

Banks of data servers, with green and red lights scrolling left and right below humming air conditioners, are sealed inside RFI-shielded containers with thick metal doors providing "radio airlocks". The staff kitchen, including a potentially intrusive microwave oven, and recreation room are hidden safely behind a lone hill ("Losberg" in Afrikaans) in isolated buildings that resemble a lunar base. A notice on the wall gives emergency contact numbers and reassurance that Carnarvon hospital is "stocked with snake anti-venom". The heavy data lifting, however, is performed hundreds of miles away at a control room beneath Table Mountain in Cape Town.

 Here, staff sit at computer screens looking at what appear to be red and yellow blobs but actually represent 10 hours' observation of galaxies such as PKS 1610-60, some 240m light years away. Dr Deborah Shepherd, project scientist and commissioning manager, has moved from her native America to join the team. "You have a fresh outlook on things in South Africa," she said. "The innovation that's coming out is incredible. They're not limited by the way things have been done in the past."

 During apartheid, South Africans have to pitch in and get on with things themselves. They are willing to change if they get it wrong. When they make mistakes, they figure out how to solve them." The project says it has created jobs for about a hundred young scientists and engineers with skills in "next generation" technologies. It has funded nearly 300 bursaries for astronomy, engineering and physics students and says astronomy is now being taught in Botswana, Ghana, Kenya, Mozambique, Madagascar, Mauritius and Zambia.

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