South Africa, Australia to share world's largest telescope

South Africa and Australia will jointly host the Square Kilometre Array, which promises to be the world's largest telescope, the international consortium in charge of the project said Friday.

The Square Kilometre Array, or SKA, is a $2-billion US radio telescope that is set to go into construction in 2016 and should be completed by 2024.

It aims to survey the sky with the help of 3,000 parabolic antennas, or dishes, and aperture arrays, a type of stationary antenna that detects mid- and low-frequency radio waves, spread across thousands of kilometres in several countries.

Combined, the radio signal-capturing capacity of all the SKA antennas will be equivalent to one giant telescope with a dish that has an area of one square kilometre — hence the telescope's name.

The antennas will be arranged in spiral arms extending from a central core to at least 3,000 kilometres away.

Optical fibres will transport the signals received by the antennas to a central supercomputer, and the data received will be processed and shared around the world.

The giant telescope will be 50 times more sensitive and scan the sky 10,000 times faster than any existing telescope. It will be powerful enough to detect airport-type radar on a planet 50 light years away and will aim to answer some of the most fundamental questions about the universe.

"Where do we come from? Where are we going? What is this universe we live in?" said John Womersley, chair of the board of directors of the SKA Organization, when describing the kinds of questions astronomers will be asking. "We don't understand what 96 per cent of our universe is made of."

An advisory committee to the SKA Organization, which includes representatives of Canada and seven other countries, had previously recommended South Africa as the sole site to host the telescope, but on Friday, the consortium announced in Amsterdam that it had settled on a dual site.

The plan to jointly operate the telescope will see Australia focus on surveying large portions of the sky quickly while South Africa, which will have the majority of telescope dishes, concentrates on observing small sections of the sky in greater detail.

"This model for splitting the SKA closely follows the workings of other observatories around the world; often separate instruments will survey the sky and inform where another telescope should look closer," said Peter Quinn, the director of the International Center for Radio Astronomy Research, a joint venture of Curtin University and the University of Western Australia, both located in Perth, Australia.

Fierce competition

The shared operation of the telescope will add about 10 per cent to the cost of construction but will expand the telescope's capabilities.

South Africa has been in fierce competition with Australia for the SKA since 2005.

South Africa led a consortium of African countries, including Botswana, Ghana and Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia, some of whom will also host parts of the telescope, while Australia's bid was submitted jointly with New Zealand.

On Friday, both sides claimed victory.

"We may feel slightly disappointed that we didn't get the whole thing, but I think one should emphasize that we did get most of it," said Justin Jonas, the chief South African scientist on the project. "Two-thirds of the biggest instrument in the world is still the biggest instrument in the world."

Quinn, meanwhile, said Australia's portion of the project plays to the country's strengths.

"Placing a major part of the SKA here shows international recognition of Australia's strength in radio astronomy and the high-quality radio-quiet site Australia has developed in Western Australia's midwest," he said.

Radio telescopes are different than optical telescopes because they detect radio-frequency signals, not light, from space. The can reveal sections of space not accessible to an optical telescope because of obstructions like cosmic dust.