www.ska.ac.za

The KAT-&7 precursor dished in the Karoo offer a glimpse of what a small portion of the site will look like if the SKA telescope bid is won by SA. If South Africa wins SKA, hundreds of dishes will be arranged in this location by 2024.

Staff Writer

THE SKA, the world’s largest radio telescope, will be able to answer probing questions that have plagued scientists for centuries, and SA is in a tight battle with Australia to become the site for the telescope.

Today, a technical evaluation of both sites is to be released to the SKA Siting Group, which reports to the SKA Founding Board. The Siting Group will weigh the process of the technical evaluation, making sure protocol was followed, and submit its assessment to the founding board.

Bernie Fanaroff, project director for SA’s SKA bid, and the SA SKA team will receive the report on February 15 at the earliest.

Regardless of where the site is located, its work will be revolutionary.

For scientists, the nature of dark energy will be among the main questions that SKA might be able to answer.

“One of the possible Nobel Prizes awarded from this telescope would be for discovering the nature of dark energy,” said Fanaroff. Other potential breakthroughs include the existence of extraterrestrial life and a challenge to Einstein’s theory of gravity.

This mega-telescope is a hot commodity, with South Africa and Australia fiercely assured of the legitimacy of their bids. The criteria that could determine the decision include:

l Radio Frequency Interference Levels: The site needs to be free from radio interference. A big draw for Australia is the remoteness of the site in the western Outback. The region, Murchison, has a large area of about 50 000km2 and a population of fewer than 150 people.

South Africa’s site in the Karoo is closer to human activity but backed by legislation that bars radio activity from the area.

According to a SKA South Africa fact sheet, Justin Jonas, associate director of Science and Engineering for SKA SA said: “A radio quiet environment does not necessarily imply a very remote location that is expensive to provide infrastructure to, and difficult to access and operate.”

l Physical Characteristics and Climate: South Africa’s physical site is located at an altitude of 1 000m, which Fanaroff said is ideal for observing the universe at high frequencies. “There is more water vapour closer to sea level, which makes viewing more difficult,” he said.

“Our site is also dry, with little cloud cover.”

While Australia has a stable climate, their team has repeatedly cited their larger baseline as an advantageous physical characteristic. The baseline is defined as the geographic distance across which a telescope’s connected antennae are distributed.

With New Zealand on board, Australia can situate antenna stations 5 500km away from its core site, a feature that may enable sharper images of the universe, according to an online article in the science magazine Cosmos. Sergei Gulyaev, astronomer at Auckland University of Technology in New Zealand, said: “For South Africa to reach the minimum SKA baseline requirements, they will have to go all the way to the Congo and many other countries have to be involved. Here you have just one country, plus New Zealand, ideally placed.”

l Cost and Infrastructure:

Simon Ratcliffe, a leading astronomer working on the SA SKA bid, told Cosmos: “Our proximity to Europe and similar time zones, coupled with value-for-money labour and good existing infrastructure, can greatly reduce the major costs of the SKA.”

The SA site is closer to existing roads and infrastructure than the isolated Australian site.

The Karoo site has connections to the national electricity grid, optical fibre backbone and road network.

“Our site has struck an ideal compromise between remoteness and proximity to infrastructure to keep costs low,” said Fanaroff.

The technical report may produce a coherent statement on which site comes out on top.