London : South Africa, Australia and New Zealand have decided to host the biggest radio telescope ever built that will sweep the sky for answers to the major outstanding questions in astronomy.
The nations belonging to the Square Kilometre Array (SKA) organisation took the decision at a meeting on Friday.
The 1.5bn-euro SKA’s huge fields of antennas will probe the early Universe, test Einstein’s theory of gravity and even search for alien intelligent life, the BBC repoted.
The project aims to produce a radio telescope with a combined collecting area of one million square metres – equivalent to about 200 football pitches.
To do this, it will have to combine the signals received by thousands of small antennas spread over thousands of kilometres.
South Africa and Australasia had put forward separate, competing bids, and the early indications had been that there would be one outright winner.
The SKA will have 3,000 antennas across a vast semi-desert part of South Africa known as the Karoo. The site is already home to seven massive Gregorian dish antennas that form part of the Karoo Array Telescope, or Kat7.
South Africa is also pressing ahead with a 64-dish project, Meerkat, which is a precursor to SKA.
Professor Justin Jonas, a director of the SKA project in South Africa, says hosting two-thirds of the telescope still means hosting the largest telescope in the world.
But the SKA organisation decided both proposals should contribute something to the final design of the telescope.
“We have decided on a dual site approach,” said SKA board chairman Prof John Womersley while speaking at a news conference held at Amsterdam’s Schiphol Airport following a meeting of the organisation’s members in the Dutch capital.
The decision to use two sites will undoubtedly increase the cost and complexity of the SKA.
Its targets will be radio sources in the sky that radiate at centimetre to metre wavelengths.
These include the clouds of hydrogen gas in the infant Universe that collapsed to form the very first stars and galaxies.
The SKA will map precisely the positions of the nearest billion galaxies. The structure they trace on the cosmos should reveal new details about “dark energy”, the mysterious negative pressure that appears to be pushing the Universe apart at an ever-increasing speed.
The telescope will also detail the influence of magnetic fields on the development of stars and galaxies. And it will zoom in on pulsars, the dead stars that emit beams of radio waves that sweep across the Earth like super-accurate time signals.
Astronomers believe these dense objects may hold the key to a more complete theory of gravity than that proposed by Einstein.
And Australia and South Africa had even started building precursor facilities, which they hoped would enhance their bids’ attractiveness.
Both these pathfinders, known as ASKAP (Australia) and Meerkat (South Africa), will now be incorporated into the early development of the network.
Most of the subsequent telescope dishes and mid-frequency aperture arrays will then be built in southern Africa (sites will include Namibia, Botswana, Mozambique, Kenya, Zambia, and even out into the Indian Ocean in Mauritius and Madagascar) – the bulk of the SKA.
The low-frequency aperture array antennas will be positioned in Australia.
“What the SKA project has decided is to put different technologies in different places, playing to the strengths of each sit,” said Prof Bryan Gaensler, from Sydney University and a former project scientist on the SKA.
And Prof Womersley told BBC News: “The important aspect of doing it this way is that we will get more science out of the project in the first phase by taking advantage of the existing ASKAP and Meerkat investments. So, while there’ll be some additional operating costs associated with this implementation, we will get more science in return.”