New Zealand and Australia are in the running to host the world’s most powerful telescope.
Artist's impression/SKA Project Development Office
Imagine a telescope so powerful it could detect an airport radar on a planet 50 light-years away. A telescope that could see so far back in time, it could witness the birth of the first stars in our universe. A telescope that could test the laws of physics and, according to astronomer Brian Boyle, “change the world”.
An international consortium has done more than imagine this telescope – it has designed it. The proposed instrument is called the Square Kilometre Array (SKA) and last month two bids to host the SKA, one from Southern Africa and one from Australia and New Zealand, were delivered to the consortium running the project. Boyle, director of the Australia-New Zealand bid, describes it as “a once-in-a-lifetime opportunity” for our part of the world.
The SKA – one of the most ambitious international science projects ever – will be the world’s largest-ever radio telescope, 50 times more sensitive and able to see 10 times further than any existing telescope. The megascience project, run by a body combining 67 organisations from 20 countries, is expected to cost more than US$1.5 billion, some of which will come from Australia and New Zealand. Radio telescopes are not that different from the instrument Galileo first pointed at the Moon 400 years ago.
“It’s just they collect light from a part of the electromagnetic spectrum that our eyes can’t see,” says Melanie Johnston-Hollitt, chairwoman of the New Zealand SKA Research and Development Consortium and a radio astronomer at Victoria University. The photons that a radio telescope collects need to be processed and digitised to be turned into an image we can look at.
Radio telescopes, invented in 1931, are already responsible for creating images of distant nebulae and galaxies and for discovering oddities like quasars, pulsars and the cosmic microwave background radiation that provides evidence of the Big Bang. Johnston-Hollitt, who is “unabashedly excited” about the project, says the SKA telescope is designed to answer five main questions: Are we alone in the universe? What is dark energy? How do galaxies evolve? Was Einstein right about general relativity? And what is cosmic magnetism?
The “square kilometre” of the SKA refers to the size of the telescope if all the receivers were grouped tightly together. In practice, the telescope will extend across more than 5000km and will include thousands of dish antennas and aperture array antennas. The centre of the proposed array would be the Murchison Radio Observatory, a “radio quiet” and remote site in Western Australia that Johnston-Hollitt describes as “one of the most pristine places on earth to do radio astronomy”.
Arrays of antennae will stretch across Australia, with two stations, one on each island, planned for New Zealand. Radio-interferometry, a sub-discipline of radio astronomy, depends on comparing the signals received at different radio telescopes. The stations in New Zealand will give the SKA its very long baseline, which will provide the telescope with excellent resolution, “the equivalent of being able to see a 50c piece in Perth, Western Australia, from here [Wellington] … that will allow us to do some cool, cool stuff.”
As well as providing more detailed images, the SKA will be able to look further back into the history of the universe. “Astronomy is kind of like archaeology – the further away your light has come from, the longer it’s taken to get to you, and the older it is. Essentially it’s like looking at snapshots of the universe’s past, so the more sensitive your telescope is, the further back you can see.”
Whereas astronomers get excited about the SKA’s ability to reveal secrets of the universe, industry and Government representatives see the strong potential for spin-off technologies in fields such as data transmission and storage, signal processing, computing capacity and renewable energy. The remarkable thing about the SKA proposal is the telescope will be so powerful that the technology does not yet exist to process, store or transmit the data it will generate. New Zealand’s recent investment in high-speed broadband, along with the KAREN data network that many universities and research organisations are already connected to, is a step in the right direction, but more technological advances are needed.
“We have to believe that Moore’s Law is going to continue,” says Johnston-Hollitt. “That’s the doubling of computer power every 18 months, so by 2020 we might be able to build the machine that we need to process SKA data.” The companies that design the hardware and software to support the SKA will, of course, benefit from being able to apply these technologies more widely. Radio astronomy is already responsible for technology now used in wireless communications, mobile phone tracking and medical imaging. “This sort of pure basic research underpins a huge amount of the technological advantages that we end up with in our daily lives,” says Johnston-Hollitt. And that’s one reason that the New Zealand Government is willing to invest in this project.
“This is an amazing opportunity for Kiwis to be involved in a world-leading project that pushes the boundaries of scientific discovery,” Economic Development Minister David Carter said last month. The decision on where to site the telescope – Southern Africa or Australia and New Zealand – will be made early next year. Construction will take from 2016-2030, with first results available from 2016.
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