1 March 2011
Africa’s bid to build and host the Square Kilometre Array (SKA) telescope – which will provide the first detailed pictures of the “dark ages” of the universe, 13.7-billion years back in time – is gaining momentum with significant scientific breakthroughs.
An important milestone was recently reached with the “detection of fringes” in a what is known among astronomers as a joint very long baseline interferometry (VLBI) observation – the first time South Africa has completed the experiment without assistance from other countries.
Africa’s first ever ‘fringe detection’
The 26-metre Hartebeesthoek Radio Astronomy Observatory (HartRAO) near Pretoria teamed up with one of the seven 12-metre dishes currently part of the Karoo Array Telescope (KAT-7) over 900 kilometres away to jointly observe and record data from a distant radio source known as 3C273.
The data was then correlated in Cape Town to produce the first ever African fringe detection at its first attempt.
“VLBI is significant as it’s used for imaging distant cosmic radio sources, spacecraft tracking, and for applications in astrometry,” Dr Bernie Fanaroff, director of the South Africa SKA Project, said in a statement released on 18 February.
“However, it can also be used ‘in reverse’ to perform earth rotation studies, map movements of tectonic plates very precisely (within millimetres), and other types of geodesy.”
MeerKAT engineers launch new ROACH board
In addition to the fringe detection breakthrough, South African engineers have also built the building block for the next generation of digital processing systems.
The reconfigurable open architecture computing hardware (ROACH) board is primarily a South African development, and already in use in 300 high-tech facilities around the globe. However, ROACH-2 prototypes are much faster and more powerful.
Why the need for such computing speed and capacity in astronomy?
“To put it in perspective, SKA is expected to collect more data in one week than humankind has collected in its entire history,” said Fanaroff.
The leap forward in technology is largely thanks to advances in field-programmable gate array (FPGA) technology. The good news is that progress in FPGA is set to hold for another four generations, so future iterations of ROACH (3,4,5 and 6) are likely in the next few years.
“This is all essential preparation for the SKA project.”
SKA ‘will revolutionise science’
“SKA will revolutionise science,” Fanaroff said. “It will be the world’s largest radio telescope and probably capable of answering questions that we haven’t even thought to ask yet.”
Expected scientific discoveries include understanding the cosmic web of neutral gas, which will unravel how the first stars and black holes were formed. It will track galaxies to investigate the rate of expansion of the universe and hopefully identify the nature of dark energy.
It will also produce three-dimensional galactic maps and detect what are likely to be extremely weak extra-terrestrial signals and pinpoint planets capable of supporting life.
It will also allow for the study of gravity, which could possibly lead to the theory of relativity being challenged. Pulsars, the collapsed spinning cores of dead stars, will also be monitored providing information on gravitational waves and black holes.
“In 2011 South Africa, in conjunction with its eight African-partner countries bidding communally for the SKA, will pull out all the stops to show the world that Africa is the future as far as science and technology are concerned,” Fanaroff said.
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