Big science tackling the big questions

The race is on to win the right for Australia to host the biggest telescope project that the world has ever seen. Known as the Square Kilometre Array (SKA), it will consist of thousands of separate radio dishes and other antennas spread across an area the size of a continent.

Merging the signals received by each of the antennas will effectively produce one giant antenna hundreds or thousands of kilometres wide—providing the sharpest-ever pictures of the sky, along with incredible sensitivity to faint signals.

A combined Australia-New Zealand effort— ‘Team anzSKA’—is competing with a southern African-based group of countries for the right to host the facility. Team anzSKA comprises the Australian Government, the New Zealand Government, CSIRO and the Government of Western Australia.

If successful, the core of the facility will be at the Murchison Radio-astronomy Observatory (MRO) site in remote Western Australia, about 300 kilometres northeast of Geraldton; but hundreds of the antennas will be scattered across Australia and New Zealand.

Australian scientists are confident that the anzSKA bid will have what it takes to win the hosting rights. “Our candidate core SKA site in outback Western Australia offers the outstanding radio quietness needed to maximise the scientific potential of the SKA,” explains Brian Boyle, SKA Project Director for Australia and New Zealand. “To capture the faint radio signals of the cosmos, a radio telescope as sensitive as the SKA needs almost perfect radio quietness,” Brian notes. “Radio noise, the bane of radio astronomers, is typically generated by human activity and the use of roads, railways, farm equipment, home electrical devices, radios and mobile phones. The MRO is the ideal environment for the SKA— naturally radio quiet and located in a region where population density and activity is extremely low.”

With up to 50 times the sensitivity and 10,000 times the survey speed of current radio telescopes, the $2.5-billion SKA will be the world’s landmark astronomical facility for the first half of the 21st century, driving innovations in antenna technology, signal transmission and processing, and super-computing.

The facility will enable researchers to tackle numerous outstanding problems in astrophysics, with particular emphasis on five key projects:

• studying the extreme environments of pulsars and black holes to put Einstein’s theory of gravity, general relativity, to its most exacting test yet
• understanding how the three major components of the Universe—matter, dark matter and dark energy—have evolved
• investigating the end of the cosmic ‘Dark Ages,’ when the first black holes and stars appeared
• probing for places and conditions where life might have arisen elsewhere in the Universe, and
• examining the origin and evolution of one of the Universe’s most enigmatic features— cosmic magnetism.

“The SKA will help unlock some of the biggest mysteries of the Universe—but more intriguingly, it is likely to make future discoveries that we can’t even begin to imagine,” says Brian, summing up the scientific potential of the SKA.

The SKA will be an international facility, funded by all the member countries. A final decision on the winning proposal will be made in 2012. Construction will begin in the second half of this decade, with completion expected by the mid-2020s.

However, astronomers won’t have to wait that long to start using powerful new radio telescopes. As part of the ‘run off’ to host the SKA, the two competitors are each building demonstrator facilities. In southern Africa it is MeerKat. In Australia, two key demonstrators are being built: CSIRO’s Australian Square Kilometre Array Pathfinder (ASKAP); and the Murchison Widefield Array (MWA), which is run by a consortium of universities and managed by Curtin University in Perth. Both will be located at the MRO.

PHOTO: CSIRO’S NEW ASKAP ANTENNAS AT THE MURCHISON RADIO-ASTRONOMY OBSERVATORY (MRO) IN WESTERN AUSTRALIA, 2010. CREDIT: WA DEPARTMENT OF COMMERCE.

CSIRO Astronomy and Space Science
Tony Crawshaw, Tel: +61 (2) 9372 4528, Tony.Crawshaw@csiro.au, www.ska.gov.au

Also in this section:

Australia’s SKA demonstrator already booked out
Tracing cosmic rays from radio pulses
Managing a data mountain
Telescope of tiles