After thirty long years of planning, on December 5th the construction of the Square Kilometer Array (SKA)the largest of the radio telescopes built to date by man and which will consist of hundreds of satellite dishes spread over two continents: the Karoo region in South Africa and Murchison County in Western Australia.
Together, the two facilities, named SKA-Mid and SKA.Low for the types of frequencies each will detect, will enable high-resolution images of the entire sky. Directed and supervised by the organization SCAO (Square Kilometer Array Observatory), in which 17 countries participate, the telescope will have such a sensitivity that it will allow researchers to capture even the weak echoes of the signals emitted by the Universe during its first days of existence.
«The SKA project – said Catherine Cesarsky, president of the SKAO board during the opening speech – has been in development for many years. Today, we gather here to mark another important chapter in this 30-year journey. A journey to deliver the world’s largest scientific instrument.” The goal is for both the South African and Australian facilities to enter service by 2030.
‘Share the sky and stars’
The Australian headquarters will house 131,072 low-frequency antennas distributed in stations that will be at a maximum distance of 65 kilometers. Together, the antennas will act like a radio telescope with a 400,000-square-meter lens. Each antenna station is two meters high and contains 256 antennas in a configuration reminiscent of a pine tree. By picking up very low-frequency signals from across the sky, SKA-Low will be able to delve into some of the oldest echoes left over from the first billion years of the Universe’s existence.
The Australian facility is on the land of the indigenous Wajarri Yamaji, who signed an agreement to ensure the telescope would not interfere with any cultural sites and that locals would receive economic and educational benefits. As part of the agreement, Wajarri Yamaji gave the site the traditional name ‘Inyarrimanha Ilgari Bundara’, which means ‘sharing the sky and stars’.
The South African headquarters, for its part, will consist of 197 large satellite dishes spread over a wide area and that will be up to 150 km from each other. Those antennas will connect to the already existing MeerKAT radio telescope and, together, they will be the equivalent of a single telescope with a 33,000 square meter lens. SKA-Mid will be five times more sensitive, four times more resolving, and 60 times faster at scanning the sky than the current Very Large Array (VLA) telescope, the state-of-the-art radio telescope located in New Mexico.
Both the Murchison Shire and the Karoo were chosen for their remoteness and the relative lack of human-made radio signals that could interfere with the detection of radio signals from outer space. Scientists around the world plan to use the telescope’s data to study questions ranging from the fundamental nature of dark energy to mysterious fast radio bursts from distant galaxies.