- Author, Jonathan Amos
- role, BBC science correspondent
One of the biggest science projects of the 21st century began its construction phase on Monday. It is the largest telescope in the world.
The Square Kilometer Array (SKA) will be the largest radio telescope in the world. It will be operational in 2028.
Split between South Africa and Australia, with headquarters in the UK, the facility will answer the biggest questions in astrophysics.
It will perform the most precise tests of Einstein’s theories and will even search for aliens.
Delegations from the eight countries leading the project will attend ceremonies in remote Murchison County, Western Australia and the Northern Cape Karoo in South Africa.
When the festivities are over, the bulldozers move in.
“That’s when it gets real,” says Professor Phil Diamond, chief executive of the Square Kilometer Array Organisation.
“It was a 30-year journey. The first 10 years were spent developing concepts and ideas. The other 10 were devoted to technological development. And then the last decade has been spent on detailed design, securing the site, permits and formalization procedures, ” he told BBC News.
The original architecture of the telescope will integrate a little less than 200 parabolic antennas”, in addition to the 131,000 dipole antennas that look like Christmas trees.
The goal is to build an efficient collection area covering an area of hundreds of thousands of square meters.
This will give the SKA unmatched sensitivity and resolution when probing targets in the sky.
The system will operate over a frequency range from approximately 50 megahertz to 25 gigahertz. In terms of wavelength, this is evaluated with units of measurement such as centimeters and meters.
This should enable the telescope to detect very weak radio signals from cosmic sources billions of light-years from Earth, including signals emitted during the first few hundred million years after the Big Bang.
The primary mission of SKA will be to trace the entire history of hydrogen, the most abundant element in the universe.
The telescope had to be able to detect the presence of hydrogen.
“SKA will contribute to advances in astronomy,” said Dr. Shari Breen, science operations manager at the observatory.
“One of them would be these ‘fast radio bursts’ that have been discovered. In astronomy, fast radio bursts, or Lorimer bursts, are bursts of radio waves that last a few milliseconds. These things produce an entire year’s worth of energy from our sun in just a fraction of a second. And we have no idea what it is? And how is this possible? I hope the SKA will have an answer. »
The telescope is built in areas already used for radio astronomy.
However, the expansion of these sites required various land deals with Karoo farmers; and with the Wajarri Yamaji, the Aboriginal title holders of Murchison.
The Wajarri community held a ceremony on Monday to inaugurate the SKA.
Various supply contracts will be announced during the ceremonies.
They will concern the total financial expenses in connection with the project. To date, the costs have been estimated at around €500 million. or £430m. – out of an expected final construction budget of €2 billion.
The first major milestone is expected to take place in 2024, when four satellite dishes in Australia and six antenna stations in South Africa will work seamlessly together as a base telescope. This test moment will then trigger the full implementation of the array.
In 2028, SKA will have an effective collection area of approximately 500,000 square metres. But the configuration is such that it can continue to grow, perhaps up to 1 million square meters.
This possibility will be possible if more and more countries join the organization and make the necessary funds available.
Current members are: South Africa, Australia, United Kingdom, China, Italy, Netherlands, Portugal and Switzerland. These countries have ratified the treaty.
France, Spain and recently Germany have entered the path to membership.
Canada, India, Sweden, South Korea and Japan have indicated their intention to participate.
“And we are also discussing with other countries under what conditions they could participate in the project,” Professor Diamond said.