The Gulf Time Newspaper One of the finest business newspapers in the UAE brought to you by our professional writers and editors.
Madrid / DPA
Work will begin in 2018 to build the largest radio telescope in the world. The Square Kilometre Array, or SKA, half located in Australia and the other half in southern Africa, will eventually become the world’s biggest single scientific instrument.
Scientists hope to use the SKA to find answers to major astrophysical questions such as how the first galaxies were formed, the true nature of “dark energy,” and whether humans are the only intelligent life-form in the universe.
“According to even the most pessimistic calculations, it is estimated that there should be at least 10 intelligent civilizations in our galaxy
that should have made contact with us by now,” said Manuel Gonzalez Garcia with the Andalusian Astrophysics Institute.
“Yet we have not been contacted,” he noted at the recent Pint of Science festival in Madrid. The SKA will make the Large Hadron Collider (LHC), a 27-kilometre-circumference ring-shaped machine in Switzerland, look tiny by comparision. The LHC is currently the world’s largest experimental facility and confirm the existence of the Higgs boson particle.
The SKA telescope hopes to eventually have more than 1 million square metres of collecting dishes – that’s the square kilometre – distributed among thousands of antennae in Africa and Australia.
If there were an airport radar located dozens of light years from planet Earth, the SKA telescope would be able to detect it.
Whereas homing in on the civil aviation of an extraterrestrial civilization is rather far-fetched, it is much more likely that the SKA will detect gravitational waves; “ripples” in the fabric of space-time caused by violent processes in the universe such as the collision of black holes.
Albert Einstein predicted the existence of gravitational waves in 1916 in his General Theory on Relativity. Einstein said that massive accelerating objects, such as neutron stars or black holes orbiting each other, would disrupt space-time in such a way as to produce “waves” of distorted space, like the waves from a stone thrown into a pond.
Using the Laser Interferometer Gravitational-Wave Observatory (LIGO), another huge scientific machine located in the United States, scientists were able this year to “listen” to the thump of gravitational waves for the first time ever.
But scientists expect the gravitational waves they will detect with the SKA will be different from the LIGO ones because they are produced at different frequencies. Gonzalez explained that LIGO had allowed scientists to detect the collision of two simple black holes, but with SKA “the expectation is to detect the collision of two super-massive black holes.” Two other major questions that scientists hope to be able to answer with the SKA have to do with the Big Bang.
On the one hand, scientists want to find out what occurred in the re-ionization period in which gas began to glow, between 500 and 1,000 years after the Big Bang. “We do not know for sure whether the stars came first and then the galaxies … Since there are no instruments able to observe that part of space evolution,” said Gonzalez.
Scientists are also uncertain as to the reason why galaxies are speeding away from each other. The reason could be “dark energy,” a mysterious substance that repels gravitation. Scientists used to think that gravity would cause the expansion of the universe to slow down; but they now believe that because of dark energy, the expansion is actually accelerating.
Radio telescopes offer alternative viewpoints to optical telescopes because they are able to detect gas that is invisible to the human eye and allow scientists to study parts of outer space darkened by cosmic dust. “To put it in understandable terms, radio astronomy allows us to study the chemical composition of the universe,” said Gonzalez.
The SKA telescope will be dozens of times more sensitive and thousands of times speedier in observing the sky than any of the current radio astronomy facilities, including the ALMA interferometer set up in the Atacama desert in Chile.
Similar to ALMA, the SKA will also work through interferometry, that is to say, observing the same object with various telescopes simultaneously. “This allows us to obtain an image with as much detail as could be obtained with a telescope as large as the distance between the antennae themselves,” said González. The SKA will be composed of two kinds of antennae.
The first stage of the project, from 2018 to 2023 with a 650-million-euro budget, will include construction of 300 parabolic antennae that receive high-frequency emissions and 130,000 dipolar antennae that detect very low frequency emissions. The parabolic antennae will be erected in South Africa and the dipolar ones in Australia.
In both locations, the sites chosen for the antennae are on ground considered sacred by local native peoples and scientists have reached agreements to plant them for 50 years after which, if there are no new negotiations, they will be taken down. In a second phase, from 2023 to 2030, remote stations will be added using what are known as aperture array antennae that provide a large field of view and are able to simultaneously observe several parts of the sky.
Other kinds of antennae will also be included to observe other frequencies. The previous phase will be also expanded until there are 2,500 parabolic antennae set up in South Africa and 500,000 dipoles in Australia. The enormous technical challenges posed by the SKA telescope project are also expected to foster new technologies that can serve society.
For example, the central SKA computer is expected to contain processing capacity equivalent to 100 million PCs and the parabolic antennae will create 10 times the current volume of global internet traffic and remote stations up to 100 times global Internet traffic.
Ten countries have joined the SKA organization: Australia, Canada, China, India, Italy, New Zealand, South Africa, Sweden, the Netherlands and Britain. Membership is expected to expand and Spain is seeking to join. Full-rights members are first on line to play a direct role in research generated by the SKA telescope and technology development to implement it.
