After 30 years of planning and negotiations, construction begins this week on the Square Kilometer Array (SKA), the world’s largest radio and astronomy observatory.
Key Points
The massive instrument – which will be built across emerging areas in Australia and Africa – will collect radio signals emitted by space objects and hopefully shed light on some of the strangest problems in astronomy, such as the nature of dark matter and how galaxies form.
On Monday, astronomers and local communities will travel to remote areas of South Africa’s Northern Cape and Western Australia to celebrate the milestone with officials from the SKA Observatory (SKAO), the intergovernmental organization that runs the telescope.
in the next 50 years,” said Lindsay Magnus, the director of the telescope being built in South Africa, based in Cape Town, South Africa. “That’s the exciting part — this is a long-term legacy.”
Years of construction
In 2012, it was decided that what was envisioned as a large telescope would have two instruments, one in South Africa and one in Australia.
The large distances between the antennas, and the total number, mean that the telescopes – called SKA-Mid and SKA-Low respectively – will pick up radio signals with unprecedented sensitivity. SKA-Low will receive frequencies between 50 megahertz and 350 megahertz and SKA-Mid will receive frequencies between 350 megahertz and 15.4 gigahertz.
Both are interferometers, where many dish-shaped antennas work together as a single telescope. The SKA will be built in phases, with the €1.3-billion (US$1.4-billion) first phase expected to be completed by 2028.
Another 700 million Euro has been earmarked for the operating costs of the telescopes over the next ten years. The ultimate goal is to have thousands of dishes in South Africa and partner countries in Africa, as well as one million horns in Australia, with a collection area of one square kilometer. The first phase is about one-tenth of the planned total project
SKA-Low
The SKA-Low telescope, in Australia, will consist of about 131,000 antennas, each shaped like two-meter-tall wire Christmas trees.
More than 500 256 antennas will dot the red sands of the site, renamed Inyarrimanha Ilgari Bundara, the CSIRO Murchison Radio-astronomy Observatory. ‘Inyarrimanha Ilgari Bundara’, the name chosen by the traditional owners of the land, Wajarri Yamaji, means ‘Sharing the sky and the stars’.
Earlier this month, Wajarri Yamaji and the Australian government signed a land use agreement that would allow the telescope to be built on Wajarri Yamaji land.
Local people will act as guardians of heritage and accompany SKAO officials before any disturbance on the ground during construction, said Des Mongoo, a community member of Wajarri Yamatji who is looking forward to the start of the work.
Once they start construction, there are opportunities for Wajarri people to participate in activities and commercial opportunities.” Scientists are also eager for the antennas to start collecting data. “[SKA-Low’s] sensitivity will enable us to see the distant universe in more detail than anything we’ve done so far,” said Douglas Bock, director of space and astronomy at the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Sydney, Australia.
This is especially exciting because we know so little about the first billion years of the Universe.” But the most interesting science will be phenomena that “we didn’t even know existed” when the telescopes were built, predicts the director of the SKA-Low telescope. Sarah Pearce, based in Perth. The first four members will be collecting data by 2024, with all arrays completed by 2028.
South Africa
On Monday, preparations to build the first major SKA-Mid dishes will begin. These will form a cluster of 197 poles, stretching over 150 kilometers in the arid Karoo region of South Africa.
Four will be completed by 2024, and more will be added by 2028. South Africa’s 64-dish MeerKAT telescope is already on site, and will be installed on SKA-Mid. In early 2022, using MeerKAT data, an international team published the most detailed image yet of the center of our galaxy1, the Milky Way, and images of mysterious radio waves emanating from the galaxy’s black hole.
The South African government and Germany’s Max Planck Society are adding 20 more dishes to the telescope, as part of an extension project. MeerKAT will be installed on SKA-Mid only at the end of its construction in 2027. “The SKA will be a huge scientific step forward,” said Erwin de Blok, an astronomer at the Netherlands Institute of Radio Astronomy in Dwingeloo and principal investigator.
MHONGOOSE’s MeetKAT program exploring galaxy formation. SKA-Mid “will help us examine nearby galaxies in more detail and see directly the gas flow in galaxies and the processes that lead to star formation.” However, the construction of SKA-Mid will interfere with MeerKAT observations, the South African Radio Astronomy Observatory said.
director Pontsho Maruping in Cape Town. Radio telescopes are very sensitive to radio waves emitted by vehicles and telecommunications equipment. “We will do everything we can to ensure that the sights are not disturbed unnecessarily,” he said. MeerKAT will continue to observe until it is installed in SKA-Mid in 2027.
By the end of the year, SKAO, based in the United Kingdom, had issued 500 million euros in construction tenders. About 70% of the contracts should go to industry in member countries.
There are currently eight full members in the organization – namely Australia, China, Italy, the Netherlands, Portugal, South Africa, Switzerland and the United Kingdom – with France planning to join.
