By Ogova Ondego
Published March 14, 2011
Africa is bidding to host the world’s most powerful radio telescope that will probe the edges of the universe, even before the first stars and galaxies that formed after the Big Bang. Known as the Square Kilometre Array (SKA), this â‚¬1.5 billion project with operating costs of about â‚¬100 million a year telescope will contribute to answering fundamental questions in astronomy, physics and cosmology, including the nature of dark energy and dark matter. This mega radio telescope is said to be about 100 times more sensitive than the biggest existing radio telescope.
Rod Marcel of SKA Africa says when the telescope is constructed in 2025, “it will have 50 times greater sensitivity than any other radio telescope on earth. The SKA will probe the edges of our universe, even before the first stars and galaxies that formed after the Big Bang. This telescope will contribute to answering fundamental questions in astronomy, physics and cosmology, including the nature of dark energy and dark matter.”
If Africa wins the bid to host the SKA, then it will be located in South Africa with several stations located in Namibia, Botwana, Mozambique, Mauritius, Madagascar, Kenya and Zambia.
South Africa is leading the African bid and has already legislated to create 12.5 million hectares of protected area – or radio astronomy reserve. This area is also referred to as the Karoo Central Astronomy Advantage Area, offering low levels of
radio frequency interference, very little light pollution, basic infrastructure of roads, electricity and communication.
Since the human story began in Africa, Marcel argues, Africa “can also be the place where we find answers to the story of our universe.”
Marcel says that at least 24 organisations from 12 countries, including Australia, Canada, India, China, France, Germany, Italy, Portugal, Spain, South Africa, Sweden, the Netherlands, the UK and the USA, are involved in this project that will consist of approximately 4,000 dish-shaped antennae and other hybrid receiving technologies.
Both South Africa and Australia have suitably remote, radio quiet areas for hosting the SKA and have competing bids to host the SKA.
If Africa wins the SKA bid, the core of this giant telescope will be constructed in the Karoo region of the Northern Cape Province near to the towns of Carnarvon and Williston, linked to a computing facility in Cape Town.
Following an initial identification of sites suitable for the SKA by the International SKA Steering Committee in 2006, southern Africa and Australia are the finalists. A consortium of the major international science funding agencies, in consultation with the SKA Science and Engineering Committee (SSEC), will announce the selected site for the SKA in 2012.
The construction of the SKA is expected to cost about 1.5 billion Euro. The operations and maintenance of a large telescope normally cost about 10% of the capital costs per year. That means the international SKA consortium would be spending approximately 100 to 150 million Euro per year on the telescope. It is expected that a significant portion of the capital, operations and maintenance costs would be spent in the host country. South Africa offers a competitive and affordable solution for constructing, operating and maintaining the SKA.
A major component of the SKA telescope will be an extensive array of approximately 3000 antennas. Half of these will be concentrated in a 5 km diameter central region, and the rest will be distributed out to 3 000 km from this central concentration. South Africa’s bid proposes that the core of the telescope be located in an arid area of the Northern Cape Province of the Republic of South Africa, with about three antenna stations in Namibia, four in Botswana and one each in Mozambique, Mauritius, Madagascar, Kenya and Zambia. Each antenna station will consist of about 30 individual antennas.
An important milestone was reached with the “detection of fringes” in a joint very long baseline interferometry (VLBI) observation. For the first time South Africa has completed the experiment without assistance from other countries. The 26m Hartebeesthoek Radio Astronomy Observatory (HartRAO) near Pretoria teamed up with one of the seven 12m dishes currently part of the Karoo Array Telescope (KAT-7) over 900 km away to jointly observe and record data from a distant radio source known as 3C273. The data was then correlated in Cape Town to produce the first ever African fringe detection at its first attempt.
South Africa’s Astronomy Geographic Advantage Act (2007) declares the entire Northern Cape Province, with the exception of the Sol Plaatje Municipality (Kimberley) as an astronomy advantage area. Within that an area of 12.5 million hectares is the main protected area – or radio astronomy reserve – for the SKA. This area is also referred to as the Karoo Central Astronomy Advantage Area.
The SKA will be one of the largest scientific research facilities in the world and will consolidate Southern Africa as a major hub for astronomy in the world. Hosting the SKA would be a major accomplishment for the Astronomy Geographic Advantage Programme (AGAP), an initiative by the South African government to establish a hub of world-class astronomy facilities in Southern Africa. Other major astronomy facilities in the region include the Southern African Large Telescope (SALT) in the Karoo, and the HESS gamma ray telescope in Namibia.
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Simon Ratcliffe, an astronomer and a member of the South African SKA bid team, has been part of the MeerKAT project (a precursor to SKA) for several years. His work includes cutting-edge astronomy, including the recent and successful very long baseline interferometry (VBLI) observations. “His astronomical colleagues are doubtful if Ratcliffe owns a pair of shoes other than a set of “plakkies” (flip flops or thongs), let’s just say that no one has even seen him wearing such items. He has a rather peculiar habit of working barefoot,” says Fanaroff, Director, South Africa SKA Project.
In the next few years, in the build up to the SKA project, RatcliffeÂ “The Barefoot Astronomer” will not only conduct his science but, more importantly, will also travel extensively promoting the benefits of the SKA project for mankind and South Africa, in particular. He will focus not only on the global scientific community and astronomists generally, but interested members of the general public. He does this in a light-hearted fashion, making use of simple, everyday terminology and, of course, barefoot.