Construction of the world’s biggest radio telescope will start next month, combining 200 large dish receivers in South Africa’s semi-arid Karoo region and 130,000 small “Christmas tree” antennas spread across the outback of Western Australia.
The giant €2bn Square Kilometre Array observatory, an international partnership between South Africa, Australia, the UK and four other countries, will be at least 10 times more powerful than existing telescopes. Astronomers say it will help them carry out research ranging from understanding how galaxies form and evolve to detecting biochemical signs of life on distant planets.
The seven founding nations of the SKA observatory on Tuesday said the technical and scientific case for the project and the funding were secure enough for construction to begin. Design and engineering preparations have been under way for seven years, with completion now scheduled for July 2029.
“I am ecstatic,” said Professor Philip Diamond, SKA director-general. “Today, humankind is taking another giant leap by committing to build what will be the largest science facility of its kind on the planet — not just one but the two largest and most complex radio telescope networks, designed to unlock some of the most fascinating secrets of our universe.”
South Africa, Australia and the UK, where the observatory’s headquarters are based, at Jodrell Bank, near Manchester, will be the biggest financial contributors to the construction costs.
The other founding members are China, Italy, the Netherlands and Portugal. “Today’s commitment by member states is a strong signal for others to get aboard and reap the benefits of participation in this one-of-a-kind research facility,” said Catherine Cesarsky, chair of the observatory’s council.
Other countries moving towards membership include France, Spain, Switzerland, Canada, Germany, India, Sweden, Japan and South Korea.
The procurement procedure for SKA contracts would start immediately, the council said. “Over the coming months, some 70 contracts will be placed by the SKAO within its member states, with competitive bidding taking place within each country.”
A huge variety of objects in outer space emit electromagnetic radiation with much longer wavelengths than the light visible to our eyes. The frequency and intensity of the signals depend on the chemical and physical processes taking place within each object.
By combining the signals received by the tree-shaped low frequency antennas in Australia and the mid-frequency dish receivers in South Africa, SKA will cover an unprecedented range of wavelengths. Powerful data processing is then able to convert the signals into images.
One challenge for the SKA, like other radio telescopes, will be future interference from the tens of thousands of satellites that operators such as Elon Musk’s Starlink plan to put into low Earth orbit to beam internet connectivity around the world.
“We are going to see them everywhere we look,” said Diamond. “We have been working with industry on mitigating actions, for example trying to get them to aim their downlink beams away from where we are.
“But we have been living with interference for as long as I have a radio astronomer — almost 40 years,” Diamond added. “Though the new satellite constellations will make our life more difficult, they will not ruin the SKA.”
Important tasks for the SKA will include studying rotating neutron stars known as pulsars, measuring gravitational waves and looking back at the early universe when the first stars and galaxies were forming.
For the first time, astronomers will be able “to detect radio emissions from planets associated with nearby stars that are comparable to those generated by human activity on Earth, opening the possibility of detecting technologically active civilisations elsewhere in our galaxy”, the SKA’s designers said.
“The search for extraterrestrial intelligence [known in science circles as Seti] is not one of our primary scientific missions but if we do find it, then ‘wow’,” said Diamond. “We will be the best Seti machine on the planet.”