Radio Telescope Boosts South Africa’s Science Credentials
By Michael Lucibella
In the last week of May, the organizing body of the largest, most advanced radio telescope, the Square Kilometer Array (SKA), revealed its decision to divide construction between candidate sites in New Zealand, Australia and South Africa. Observers have called the split decision a political move, but it reflects how strong both proposals were (Australia and New Zealand submitted jointly as one single bid). South Africa, considered an underdog in the early 1990s when the project was first announced, has shown that it has become a scientific powerhouse on the African continent.
The SKA is so named because the total collecting area of all the dishes, antennas and aperture arrays will total about one square kilometer. South Africa will be home to the mid- and high-frequency antennas. The telescope will be spread out over a huge distance, with antennas as far away as 3,000 miles from its core cluster of dishes. Seen from afar, the telescope’s layout resembles a spiral galaxy, with a dense five-kilometer diameter core of dishes and antennas at its center and long arms spiraling out across the continent.
Radio telescopes already dot the Northern Cape Province at the site where the heart of South Africa’s SKA will be built. On the arid Karoo plains in the western part of the country, seven radio dishes, each 12 meters across, started listening to the skies in 2009. The array, known as KAT-7, is the precursor to another, even bigger array known as MeerKAT. Already under construction, the telescope will ultimately be made up of 64 dishes total, each 13.5 meters across. Ultimately MeerKAT will become part of the larger SKA as construction on the international project goes forward. As it stands, the South African government is planning to have MeerKAT ready to start collecting data by 2016.
“MeerKAT is a done deal. The South African government has committed two billion rands [about $240 million] to build it,” said Nithaya Chetty, a professor at the University of Pretoria and former president of the South African Institute of Physics.
KAT-7 is not the first radio telescope in the country. In 1961 the United States built a 26 meter radio dish outside Johannesburg as part of NASA’s Deep Space Network used to track its space missions. In 1974, after the end of the manned lunar program, NASA relinquished control of the dish to South Africa and it became the Hartebeesthoek Radio Astronomy Observatory. A test dish for MeerKAT was built at the site.
As part of its bid for the Square Kilometer Array, South Africa has partnered with several other countries across the continent, including Ghana, Kenya, Namibia, Botswana, Mozambique, Mauritius and Madagascar. As part of the collaboration, South Africa has been helping either to build new radio telescopes in these countries, or to convert existing radio dishes into stellar observatories.
With its unique position in the Southern Hemisphere, South Africa has had a long history of stargazing, one of the reasons it has been selected for the Square Kilometer Array.
“Astronomy is very big in South Africa, we have an almost 200 year history of astronomy,” Chetty said. In 1820 the first observatory was built in Cape Town. Over the next hundred years, European colonists continued to build observatories across South Africa to take advantage of the dry air and dark skies.
Today the South African Astronomical Observatory is the overarching organization that operates seven optical and infrared telescopes across the country, under the management of the National Research Foundation.
“The real jewel is, of course, the Southern African Large Telescope,” Chetty said. The SALT, as it is more popularly known, is a 9.2 meter diameter reflecting telescope on the Karoo plains, the largest optical telescope in the Southern Hemisphere. It opened its bay doors to the heavens in 2005, and since then has become one of the premier telescopes south of the equator.
Also in 2005, the South African Institute of Physics released the report “Shaping the Future of Physics in South Africa.” The study provided an assessment of the current state of physics in the country, and a roadmap of where to go and the big issues that needed to be addressed.
“What the nation has to do is to invest in the human capital,” said S. James Gates of the University of Maryland, one of the authors of the report. The lingering effects of apartheid are still being felt, and there is still a huge disparity in education between black and white citizens. “The system had to find a way to involve the majority of South Africans.”
The study offered a number of suggestions on ways to increase the profile of physics in the country, and encourage more students to pursue physics and science degrees. These included better elementary and secondary school education, a concerted effort to integrate historically white universities and historically black universities, a national campaign showing that physics degrees are sought after by employers, and an improved broadband internet infrastructure.
“We also suggested that there were some flagship initiatives that would be useful to providing overarching paradigms for the community,” Gates said.
The SKA is one such initiative, as is the African Laser Center. Between the 1960s and 1980s, the apartheid government developed a small nuclear arsenal before dismantling their stockpile and discontinuing the program in 1989. The equipment used to manufacture and design the nuclear weapons was then repurposed for other scientific research. At the time, the South African government was at the forefront of experimenting with lasers to enrich uranium. Much of the advanced laser equipment was used to develop the National Laser Center in Johannesburg in 2000. The center expanded its mission in 2003, and helped to found the African Laser Center, an international collaboration of laser labs across Africa.
“Now laser scientists all over the continent are working together, they know what they’re doing,” said Sekazi Mtingwa, a professor at MIT who helped found the African Laser Center. “We were able to make the connection and transform the entire culture of laser science in South Africa.”
Another initiative is a proposed South African synchrotron light source. Although this is still in the preliminary design phase, the scientific community has been working to build up its expertise. There already exist a number of smaller accelerators throughout the country organized through the nations iThemba LABS; Mtingwa and his colleagues, however, have been calling for a larger, third-generation synchrotron light source.
Students have been traveling to light sources around the world to ready a future generation of researchers and technicians. In addition, the Department of Science and Technology has been working to make South Africa an associate scientific member of the European Synchrotron Radiation Facility located in Grenoble, France. The plan is next to build a beamline at the ESRF owned entirely by South Africa, before construction of a full facility in the country.
“I think one of the biggest benefits of a synchrotron light source is that graduate students can do frontier work there without traveling abroad,” said Herman Winick, a research professor at SLAC who has been a vocal international advocate for a South African synchrotron.
In December, the country hosted a conference on synchrotron science to help promote the construction of such a light source. The proposal is just starting to gain traction. The South African government recently asked for a white paper describing the necessary steps to build a light source in the country. The biggest potential obstacle is likely to be the cost of such a facility, as much as $1 billion by some estimates. The construction and operation of the Square Kilometer Array will be a big part of South Africa’s science budget in the coming years, and promoters of a synchrotron worry that the government won’t opt to pay for the two.
“I can imagine it would be difficult. It would be wonderful if they did both,” said Mtingwa, who has also been a strong advocate for bringing a synchrotron to South Africa. “I would have to be optimistic regardless of what happens with the SKA… In ten to twenty years I think they will get one.”
Despite an uncertain future, scientists from the country have continued to prepare for the day the light source is ready.
“Where we are at currently, I think we’re still in the process of building up our capacity,” Chetty said. He added that the plan for a synchrotron has been slowly building momentum for a decade, but the cost of the SKA would likely postpone its construction. “Not likely in the near future, but that’s not to mean it’s off the agenda… When the time is more opportune I think it will be built up.”