The starlight that we see at night is only a fraction of what is out there. Stars and galaxies don’t just emit visible light but a range of electromagnetic radiation, including UV radiation, X-rays and radio waves. Most of this radiation is invisible to humans.
Special telescopes are required to detect radiation such as radio waves. It has now been announced that part of the world’s largest radio telescope will be built in Australia. The $2.5 billion Square Kilometre Array (SKA) will consist of thousands of antennas concentrated in the Mid West Radio Quiet Zone in Western Australia, as well as southern Africa.
Radio waves are emitted by a range of astronomical sources, including stars and clouds of gas and dust. These radio waves are similar to those made by communications systems on Earth. Radio signals that reach the Earth from space can be drowned out, which is why places like the Australian outback and southern Africa are ideal locations for the SKA. Their distance from large population centres means that interstellar signals can be heard above the background radio noise.
While the radio waves are hard to detect, the bigger the telescope, the easier it is to pick them up. The thousands of dishes and other detectors of the SKA will cover an area of approximately one square kilometre, making it the biggest radio telescope. Its huge size means that it will be 50 times more sensitive than the best radio telescopes currently available.
The SKA will be used to investigate the formation of the first stars in the Universe, the mysterious force of gravity and possibly even search for extraterrestrial life. By hosting part of this important scientific endeavour, Australia will continue to support research that investigates some of the mysteries of the Universe.
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