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Siting decision due on Square Kilometre Array

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Published: 25th May 2012 02:47:58

A decision is due later on where to site one of the great scientific projects of the 21st Century.

Australia and South Africa have been competing to host the 1.5bn-euro (£1.2bn) Square Kilometre Array, a giant next-generation radio telescope.

The SKA's huge fields of antennas will sweep the sky for answers to the major outstanding questions in astronomy.

They will probe the early Universe, test Einstein's theory of gravity and even search for alien intelligent life.

Nations belonging to the SKA Organisation are meeting in a hotel at Schiphol Airport, Amsterdam, to make the decision.

It has been widely reported that South Africa edged out Australia in the technical assessment of the rival bids, but it is down to the members to make the final judgement.

The project aims to produce a radio telescope with a collecting area of one million square metres - equivalent to about 200 football pitches.

Pallab Ghosh visits Jodrell Bank where the SKA project team is based

To do this, it will have to combine the signals received by thousands of small antennas spread over a distance of more than 3,000km.

This practice, known as interferometry, was pioneered by radio astronomers, but the SKA will push the approach to new levels to create a superscope with remarkable sensitivity and resolution.

Its targets will be light 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 maps precisely the positions of a 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 map out 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 which sweep across the Earth like super-accurate time signals.

Astronomers believe these super-dense objects may hold the key to a more complete theory of gravity than that proposed by Einstein.

The competition between Australia and South Africa has been intense but friendly.

The countries were shortlisted because they each have territories that enjoy very little radio interference from the likes of cellular phones and TV transmissions.

For Australia, the array would be centred on a site at Boolardy Station, about 500km (310 miles) north of Perth in Western Australia. For South Africa, the central location would be in the Karoo in the Northern Cape, about 95km from Carnarvon.

But the sheer scale of the SKA means individual radio antennas would spread to New Zealand in the case of the Australian architecture, and into a number of neighbouring states and even Indian Ocean islands in the case of South Africa.

Whichever bid comes second will walk away with a very decent prize - a smaller radio astronomy facility built as a precursor during the bid process.

Both the Australian Square Kilometre Array Pathfinder (ASKAP) and the Karoo Array Telescope (known as Meerkat) will do world class science irrespective of whether they are eventually incorporated into the SKA.

As well as being a scientific marvel, the Square Kilometre Array is also a mighty engineering challenge.

It will generate prodigious amounts of data that have to be channelled through a vast fibre-optic broadband network; and that information will have to be processed by the fastest supercomputer available. The design calls for an exaflop system - a system capable of carrying out a million, million, million (quintillion) floating point operations per second.

Such a system does not yet exist, but the SKA Organisation is banking on the fact that it will by the time the project is fully up and running in the early 2020s.

The member nations meeting at Schiphol Airport will be asked to come to a unanimous endorsement of one of the bidders.

One complicating factor concerns a report ordered by the SKA board in April that sought to evaluate the feasibility of splitting the SKA across Australia and South Africa.

If the members are satisfied this is a non-starter (it would certainly be more expensive), they are back to a simple choice.

Votes can be cast at Friday's gathering by the UK, Netherlands, Italy, China and Canada. Australia, New Zealand and South Africa will not vote; neither will India, as an associate member.

There will be a major industrial return for all members, irrespective of where the SKA is finally positioned.

The next project engineering phase is worth about 90m euros. Phase 1 of the project, due to start in 2015/16, is valued around 360m euros. The cost of the last phase will not be known until final detailed design work is done, but is likely to exceed 1.2bn euros.

Jonathan.Amos-INTERNET@bbc.co.uk and follow me on Twitter

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BBC News, 2012. Siting decision due on Square Kilometre Array [Online] (Updated 25th May 2012)
Available at: http://www.ukwirednews.com/news/1430816/Siting-decision-due-on-Square-Kilometre-Array [Accessed 24th Apr 2014]

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