Science and technology

Africa to co-host Square Kilometre Array

It will be capable of probing the edges of our universe. It will search for gravitational waves, predicted but never detected. It will be a virtual time machine, enabling scientists to explore the origins of galaxies, stars and planets. And South Africans are at the heart of its development.

South Africa, allied with eight other African countries, is competing against Australia (allied with New Zealand) to host the 1.5-billion Square Kilometre Array (SKA), an instrument 50-100 times more sensitive and 10 000 times faster than any radio imaging telescope yet built.

The international science funding agencies and governments involved in the international SKA consortium are due to announce the winning bidder in 2012, with construction likely to start in 2016 and take place in phases over several years, with completion by about 2022.

More than 70 institutes in 20 countries, together with industry partners, are participating in the scientific and technical design of the SKA telescope, which will be located either in Australia and New Zealand or in southern Africa extending to the Indian Ocean Islands.

The design, construction and operation of the telescope will have a potentially massive impact on skills development in science, engineering and associated industries, not only in the host countries but in all project partner countries.

The SKA project will drive technology development in antennas, fibre networks, signal processing, and software and computing, with spin-off innovations in these areas set to benefit other systems that process large volumes of data.

'Time machine'

At between 50 to 100 times more sensitive than any existing radio telescope, the SKA will be able to probe the edges of our universe, and help us to answer fundamental questions about the laws of nature and physics, including the study of so-called "dark energy" and "dark matter".

It will subject Einstein's theory of general relativity to its most stringent tests yet, and will search for gravitational waves, which have been predicted but never detected.

It will be a powerful virtual time machine, enabling scientists to "go back in time" to explore the origins of the first galaxies, stars and planets. If there is life somewhere else in the Milky Way galaxy, the SKA will help us find it.

According to the South African SKA project office, the operations and maintenance of a large telescope normally cost about 10% of the capital costs per year, meaning the international SKA consortium would be spending approximately 100-million to 150-million a year on operating and maintaining the telescope.

"It is expected that a significant portion of the capital, operations and maintenance costs would be spent in the host country," says SKA South Africa's Kim de Boer.

The SKA in Africa

The completed telescope will comprise around 3 000 antennas with a combined collecting area of roughly one square kilometre.

South Africa plans to locate the core of these in the Karoo region of the Northern Cape an arid, remote area blessed with exceptionally clear skies and minimal radio interference with outlying stations in Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia.

The major component of the SKA telescope receptor will be an extensive array of approximately 3000 antennas, half of which will be concentrated within a five kilometre diameter of the central region, with the rest distributed up to 3000km from this central concentration. These antennas will be 12-15 metre diameter dishes.

South Africa plans to locate the core of these in the arid Karoo region of the country's Northern Cape province an arid, remote area blessed with exceptionally clear skies and minimal radio interference with outlying stations in Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia. Added together, the combined collecting area of these antennas will be roughly one square kilometre.

The antennas would be connected via a super-fast data communications network to an extremely large and powerful computer in the Northern Cape, and the telescope would be controlled and operated remotely from Cape Town, where the operations and science centre would be located.

De Boer says the SKA will be one of the largest scientific research facilities in the world and, if awarded to South Africa, would consolidate the southern African region as a major international hub for astronomy and cutting-edge technology.

It would attract the best scientists and engineers to work in Africa, and would provide unrivalled opportunities for scientists and engineers from African countries to work on cutting-edge research and collaborate in joint projects with the top universities in the world.

Why the Northern Cape?

The Karoo region of South Africa's Northern Cape province is ideal for radio astronomy, because it is remote and sparsely populated, with a very dry climate.

There is minimal radio frequency interference from man-made sources such as cellular phones and broadcast transmitters, which is crucial for radio astronomy, as radio interference would "blind" the telescope.

In 2007, South Africa's Parliament passed the Astronomy Geographic Advantage Act, which declares the Northern Cape an "astronomy advantage area", giving the Minister of Science and Technology powers to protect the area from future radio interference.

An area of 12.5-million hectares around the proposed core of the SKA will be protected as a radio astronomy reserve, with regulations controlling the generation and transmission of interfering radio signals in and around the area around.

MeerKAT: world-class SKA precursor

South Africa is no newcomer to major league astronomy. The Northern Cape is already home to one of the world's largest telescopes, the Southern African Large Telescope or SALT.

South Africa also works closely with neighbour Nambia on the HESS gamma ray telescope, and is currently building an 80-dish precursor instrument for the SKA, the Karoo Array Telescope (also known as the MeerKAT).

Regardless of whether South Africa wins the SKA bid, the MeerKAT will be a powerful scientific instrument in its own right, comprising 80 dishes each 13.5-metres in diameter. It is being built adjacent to the site proposed for the SKA, in a radio astronomy reserve near the small town of Carnarvon in the Northern Cape, where it is due to be commissioned in 2014/15.

An engineering test bed of seven dishes, called the KAT-7, is already complete.

In the process of building the MeerKAT, South African engineers are already working on some of the SKA's technological building blocks such as a prototype dish antenna that combines new materials with innovative design processes to meet the SKA's exacting precision, durability and cost criteria.

MeerKAT: scientific programmes

The MeerKAT will be the most sensitive centimetre-wavelength radio telescope in the Southern Hemisphere, and astronomers from around the world are already queuing up to use it.

Following an October 2009 invitation for applications for telescope time to perform large survey projects, 21 proposals involving more than 500 astronomers from around the world including 59 from Africa were received.

A committee made up of local and international experts rated the proposals on the basis of their scientific merit, technical feasibility, the resources each group was prepared to bring to the project, and the extent to which the MeerKAT had a unique role to play in the proposed projects.

In total, more than 43 000 hours of observation time have been allocated, of which nearly 8 000 hours were allocated to a proposal to test Einstein's theory of relativity and investigate the physics of enigmatic neutron stars as part of a radio pulsar timing survey.

In addition, 5 000 hours will be dedicated jointly to two proposals requiring an ultra-deep survey of neutral hydrogen gas in the early universe.

The objectives of these studies coincide with those of the first phase of the SKA telescope itself, confirming the MeerKAT's status as a SKA precursor instrument.

MeerKAT-SKA collaboration

According to the local SKA project office, the MeerKAT's scientific programme will be a mixture of "blind" and "directed" surveys conducted by large project teams, and smaller experiments designed by individual principal investigators or small teams. These teams and principal investigators will be international in their composition, and will include participants from Africa.

The MeerKAT scientists are fully embedded in the international SKA project, participating in technical committees and working groups set up by the SKA project development office.

Bilateral agreements have been established with key institutions involved in the international SKA consortium, including the Universities of Oxford and Cambridge, the University of California at Berkeley and Caltech, the National Radio Astronomy Observatory (NRAO) of the USA, the national radio astronomy centre in India, and thee radio astronomy institutes in Italy.

In South Africa, the Hartebeesthoek Radio Astronomy Observatory and the South African Astronomical Observatory are participating in the MeerKAT project, while researchers and students at many universities in South Africa and the rest of Africa are also actively participating.

The local SKA project's head office is in Rosebank, Johannesburg, while the MeerKAT engineering office is in Pinelands, Cape Town. The Department of Science and Technology is funding the SKA project via the National Research Foundation.

Connectivity boost for SALT, SKA

In October 2010, the Council for Scientific and Industrial Research (CSIR) announced that it would be installing a R100-million ultra-high speed broadband link between the Northern Cape sites of both the Square Kilometre Array and the Southern African Large Telescope (SALT) and the SA National Research Network backbone in Cape Town.

The ultra-high speed link will enable local and international researchers to process data from SALT and the KAT-7/MeerKAT in near real time, and significantly boost South Africa's bid to host the SKA.

The installation of the new link will demonstrate "that South Africa can provide the bandwidth needed to fulfil the requirements of the full SKA, and will serve as a significant boost to the South African SKA bid," said Department of Science and Technology chief director Daniel Adams.

National Research Foundation CEO Albert van Jaarsveld said the development paved the way for international collaborators to actively make use of the facilities that will be provided by the two telescope sites.

"Furthermore, the broadband link demonstrates our ability to invest heavily in scientific infrastructure in support of our desire to win the SKA bid."

Skills development and training

The SKA South Africa project, including the MeerKAT telescope, is one of the biggest science and engineering projects in South Africa. It thus represents an unrivalled opportunity for the development of very high-level science and technology expertise paving the way for Africa to contribute significantly to the global knowledge economy and global technology trade.

These technologies include very fast grid computing, very fast data transport, data storage, wireless engineering, digital electronics, image processing and software development.

In 2005, the South African SKA project initiated a targeted "Youth into Science and Engineering Programme" to develop highly skilled young scientists and engineers.

"The young people supported by this programme will serve South Africa, and our African partner countries, in the future in key areas of economic development in addition to their participation in 'blue skies' scientific research," says Kim de Boer.

The programme offers comprehensive bursaries to students in engineering, mathematics, physics and astronomy at undergraduate and postgraduate level. Bursary holders also benefit from regular workshops and conferences where they interact with the world's leading astronomers.

SAinfo reporter

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Artist's impression of the Square Kilometre Array Artist's impression of the core of the Square Kilometre Array. The full facility will comprise around 3000 antennas with a combined collecting area of roughly one square kilometre (Image Swinburne Astronomy Productions / Square Kilometre Array) South Africa, Russia sign satellite pact

Three of the seven antennas of the KAT-7 demonstrator radio telescope outside Carnarvon in the Northern Cape province. The KAT-7 is paving the way for the 64-dish Karoo Array Telescope (also known as the MeerKAT), due to be commissioned in 2015/16 as a precursor to the SKA - and as one of the most powerful telescopes in the world in its own right (Photo: SKA South Africa)

Listening to the early Universe

Astronomers explore the universe by passively detecting electromagnetic radiation and cosmic rays emitted by celestial objects. The earth's atmosphere shields us from much of this radiation, so modern astronomy is done from large optical telescopes on high mountains, or from orbiting satellite observatories.

Radio astronomers, on the other hand, concentrate on the relatively long wavelength (or low frequency) radio waves that penetrate the earth's atmosphere with little impediment or distortion.

Because electromagnetic radiation travels at a fixed speed of about 1.08 billion km/h, very distant objects are observed as they were in the distant past. Astronomers are therefore able to "look back in time" to observe the early stages of the evolution of the universe.

Most existing radio telescopes were built 10 to 30 years ago. For radio astronomy to progress, a new telescope with 100 times the collecting surface of existing telescopes will be needed in about 10 years' time.

The SKA will probe the so-called "Dark Ages", when the early universe was in a gaseous form before the formation of stars and galaxies. At present, astronomers do not have the necessary tools to observe radiation from this period of the universe, which extends from about 300 000 years till one billion years after the Big Bang.

Radiation reaching us from the "Dark Ages" has travelled a huge journey through space, and is in the form of radio signals emitted by the neutral hydrogen gas that dominated the universe during this period. The signals are, however, extremely faint, and require a telescope with the planned sensitivity of the SKA to be detected.

The SKA will map the time evolution of this cosmic web of primordial gas as it condenses to form the first objects in the universe. It will also chart the development of these adolescent stars and galaxies, which will provide us with information about our own origin. The atoms in our bodies, our planet and our star were formed by the nuclear reactions that powered these early stars.

Source: Square Kilometre Array SA

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