SKA created the first image and opened the prospect of new scientific discoveries
Radio waves — at the far end of the electromagnetic spectrum — longer than visible light waves. This is why radio astronomy benefits from large antenna distances. The greater the distance between the antennas, the clearer the telescope «sees» radio waves. Back in the 1990s, astronomers were planning an extremely large radio telescope, the largest to date.
SKA stands for «Square Kilometer Area» (Square Kilometer Array). When its first phase is completed in the late 2020s, it will be the largest radio telescope in the world. Its antennas will be located at two sites — one in Australia and the other in South Africa (and eventually several other African countries). The Karoo site in South Africa will have 197 dish antennas. On January 25, 2023, the SKA Observatory reported that the Karoo telescope prototype, called SKAMPI, saw “first light” and obtained the first data of the southern sky.
The image shows the radio emission from the center of our Milky Way galaxy and the radio source at the heart of the Milky Way Sgr A* (most likely associated with the black hole at the center of our galaxy), as well as the bright radio galaxy Centaurus A and both the Magellanic Clouds (large and small), and some areas star formation in the Milky Way.
The prototype antenna of the South African SKA, called SKAMPI (an acronym for Square Kilometer Array and the Max Planck Institute for Radio Astronomy), is itself a radio telescope. He will study pulsars and radio emission from the Milky Way. But this is far from his only goal. SKAMPI — this is a prototype of the 197-disk antenna array that will form the South African part of the SKA Observatory.
In radio astronomy, combining many telescopes into a so-called interferometric array increases resolution: the larger the telescope, the better the resolution, but practical limitations prevent building a telescope so large. At the moment, China's FAST is the largest single radio telescope in the world, with a diameter of 500 meters. In the case of SKAO, this will be a telescope with a diameter of 150 kilometers.
In 2021, the Square Kilometer Array initiative became an intergovernmental astronomical organization, second only to the European Southern Observatory (ESO), and currently includes nine participating countries. In December 2022, SKAO held groundbreaking ceremonies for both of its observatories and began the construction phase.
The first image from the full observatory will likely be difficult to determine as the antennas begin to be used as they are built. However, if we take into account the experience of the previous MeerKAT observatory located at the same site, we can expect some exceptional scientific discoveries as this radio observatory scales up. By the way, 64 MeerKAT antennas will be included in the final SKA along with SKAMPI and its subsequent similar antennas.