Australia or South Africa -- One Will be Home to Radio Astronomy's Square Kilometre Array. (September 29, 2006)

    Four nations were in the running to site radio astronomy's Square Kilometre Array (SKA), Argentina, Australia, China and South Africa. Taking a month to visit the four proposed remote sites the search committee of seven has now eliminated Argentina and China.

Artist's impression of the core site of the Square Kilometre Array if it is based in Australia.  Credit: CSIRO

The SKA gets its name from the approximate total area of its multiple dish antennas, and it is being developed by researchers in 17 countries.

Rob Millenaar of the Astron observatory in the Netherlands, and leader the search group said,  "The general idea is that you want to have the instruments set up in a region that's as far away from human activity as possible."

According to Phil Diamond, a member of the 21-strong steering committee the search committee determined that while all four of the proposed sites were quiet enough for the SKA,  in China, the "dramatic, vegetation-clad hills" presented significant problems and the site didn't allow fitting the design into the landscape."

Jenny Hogan of news@nature.com reports, "The Argentine bid lost out because of turbulence in the ionosphere over the site. The shape of the Earth's magnetic field directs charged particles into the atmosphere near the area, causing oscillations that muddle the propagation of low frequency radio waves."

And according to Ms Hogan, "Six key science projects have been proposed for the telescope, including a study of the mysterious 'dark energy' driving the expansion of the Universe, probes of the era in which the first stars switched on and imaging of planet-forming regions. Astronomers also hope that the telescope's unprecedented sensitivity will turn up entirely new phenomena."

The Australian bid, led by Brian Boyle of CSIRO's Australia Telescope National Facility proposed to erect thousands of antennas in the Western Australian desert at Mileura Station, 100 kilometres west of Meekatharra and 350 kilometres north-east of Geraldton. Thousands additional antennas will be placed across the continent, with some possibly positioned in New Zealand.

South Africa proposes to place the centre of the SKA in the Karoo desert, with additional dishes set up in countries such as Botswana and Ghana. as well as on the island of Madagascar.

News@nature says, "While the shortlist was based on scientific merit, the final decision on the telescope's home is likely to be determined by money and politics."

Currently the time timeline for the SKA schedules the telescope's overall design to be fixed in 2009 with funding arranged for construction to begin in 2011 and operation to commence in 2014.

The current forecast of overall cost is about US$1 billion and Science's Robert Koenig reports, "Some doubts remain about funding, with the U.S. National Science Foundation so far avoiding a firm commitment. But Boyle says he is confident that SKA will eventually be built: 'It is too good of an astronomy opportunity to pass up.'"