Conceptual diagram of SKA-Low antenna array. Image source: DISR
After 30 years of planning and negotiations, construction began this week on the world's largest radio astronomy observatory, the Square Kilometer Array (SKA). The massive instrument, to be built in Australia and Africa, will collect radio signals from celestial objects and promise to provide clues to some of astronomy's most mysterious questions, such as the nature of dark matter and how galaxies form.
"We're basically laying the groundwork for the next 50 years of this instrument," said Lindsay Magnus, who led the telescope's construction in South Africa. "It's exciting — it's a long-term legacy."
The giant telescope was originally envisioned to consist of two facilities, one in Australia and the other in South Africa, called SKA-Low and SKA-Mid. The distance between and the sheer number of its antennas means the telescope array will pick up radio signals with unprecedented sensitivity. SKA-Low will detect frequencies from 50MHz to 350MHz, while SKA-Mid will detect frequencies from 350MHz to 15.4GHz.
The SKA will be built in stages, with the first phase costing 1.3 billion euros and expected to be completed in 2028, with an additional 700 million euros earmarked for operating the telescope over the next 10 years. SKA's ultimate goal is to build thousands of antennas in South Africa and African partner countries, and 1 million antennas in Australia, with a total collection area of 1 square kilometer. The first phase accounts for about 1/10 of the entire project plan.
Australia's SKA-Low telescope will consist of about 131,000 antennas, each shaped like a two-meter-tall wire Christmas tree. More than 500 arrays of 256 antennas will dot the red clay of the observatory, which has been renamed the CSIRO Murchison Radio Astronomy Observatory. The first four of these arrays will begin collecting data in 2024, with all arrays to be completed by 2028.
Scientists are eager to collect data with the new antenna. Douglas Bock, director of space and astronomy at the Commonwealth Scientific and Industrial Research Organization in Australia, said: "SKA-Low's sensitivity will allow us to observe the distant universe in the most detailed way to date. Years know very little."
"But the most exciting will be phenomena that were 'never known to exist' when the telescope was designed," said Sarah Pearce, head of the SKA-Low telescope.
On December 5, preparations began for the construction of the first antenna of South Africa's giant SKA-Mid telescope. The antennas consist of 197 antennas and extend about 150 kilometers across the arid Karoo region. Four antennas will be built in 2024 and more will be added in 2028.
The existing 64-dish MeerKAT telescope in South Africa will eventually be incorporated into the SKA-Mid telescope. In early 2022, an international team used MeerKAT data to release the most detailed image yet of the center of the Milky Way, as well as images of mysterious radio lines emanating from the Milky Way's black hole. The South African government and the Max Planck Society in Germany will add 20 more dishes to the telescope as part of the expansion project. MeerKAT will be integrated into SKA-Mid at the end of construction in 2027.
"SKA will be a huge step forward for science," said Erwin de Blok, astronomer at the Netherlands Institute for Radio Astronomy and principal investigator of the MHONGOOSE large-scale galaxy formation observation program at MeerKAT. SKA-Mid will help us study nearby galaxies in more detail. , and directly probe the flow of gas into galaxies and the processes that lead to star formation."
However, Pontsho Maruping, director of the South African Radio Astronomy Observatory, said the construction of SKA-Mid would interfere with MeerKAT observations. Radio telescopes are particularly sensitive to radio waves emitted by vehicles and communications equipment. We will do our best to ensure that observations are not unduly interrupted. She revealed that MeerKAT will continue to observe until it is incorporated into SKA-Mid in 2027.
It is reported that the UK-based SKA intergovernmental organization has announced a construction tender project of 500 million euros, of which about 70% of the contracts must be provided to the industrial sectors of the member countries. The organization currently has 8 official members, namely Australia, China, Italy, the Netherlands, Portugal, South Africa, Switzerland and the United Kingdom, and France also plans to join.
(The original title was "Construction of the world's largest radio astronomy observatory - located in Australia and South Africa, forming an ultra-sensitive square kilometer array")
