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Something Kind of Awesome

An elevated view of four of CSIRO’s new ASKAP antennas at the Murchison Radio-As

An elevated view of four of CSIRO’s new ASKAP antennas at the Murchison Radio-Astronomy Observatory, October 2010. Credit: Ant Schinckel, CSIRO

By Brian Boyle

This month Australia and New Zealand join forces to submit their bid to host one of the biggest science projects ever – the Square Kilometre Array radio telescope.

Radio astronomy provides us with a unique view of the universe – a view of the cold hydrogen gas between the stars, a view of exotic objects such as pulsars and quasars, a view through the obscuring dust, and a view of cosmic magnetic fields. This is a view that complements those obtained with optical, X-ray, microwave and gamma-ray telescopes, completing the electromagnetic symphony of the universe.

The vast collecting areas of the new generation of telescopes allow astronomers to look further out into the universe. Since the light received from ever-distant objects – be it visible, radio, X-ray or gamma-ray – takes a finite time to travel to us, when we look out we also look back in time. Just as palaeontologists would piece together the evolution of life on Earth by digging down and back through the fossil rock embedded in the rock strata, astronomers – as cosmic palaeontologists – peer out ever deeper into the universe and further back in time over billions of years to understand the evolution of the universe itself.

The faintness of the radio signals from cosmic objects has been the biggest barrier to probing the early universe using radio astronomy. All of the astronomical radio emissions ever collected over the entire history of radio astronomy amounts to less energy than a snowflake hitting the ground. Astronomers need vastly bigger radio telescopes.

Enter the Square Kilometre Array (SKA), an internationally-funded telescope project first conceived in 1991 that will help us see back more than 13 billion years to when the first stars formed in the universe.

Vastly more sensitive than any existing radio telescope, the SKA is a next-generation radio telescope that will push back the frontiers of astronomy. Its mammoth collecting area of one square kilometre – 1,000,000 m2 – is more than ten times the size of the largest modern radio telescope.

The SKA isn’t a single telescope. Quite apart from the impracticality and cost of building a single antenna of this size, its collecting area is achieved by combining the signals from many smaller antennae scattered over a large area. This improves the detail of images that are constructed when the signals from each telescope are brought together.

The SKA will be made of 3000 mechanically-steerable dish antennae accompanied by many fixed antennae capable of receiving frequencies from the FM band to almost the microwave band. About half of the antennae will be tightly clustered in a central core zone, with the remainder at remote stations spread out at increasing distances from the core across a continent or more in scale (see figure below).

The antennae will be linked together by a broadband network that is capable of handling speeds up to 100 Tb/s. This is ten times greater than the total global internet traffic today. The data will be collected and processed by the world’s fastest supercomputer – not the world’s fastest supercomputer today, but the world’s fastest supercomputer in 2020 and beyond, when this telescope will be fully operational. This computer will have a capacity of 1 ExaFlop, or 1018 operations per second.

At its heart, the SKA is an IT telescope. Its future flexibility and upgradability will be ensured more by advances in IT than in the antennae and receivers themselves.

Probing the universe in such detail will let astronomers tackle fundamental unanswered questions about the universe:

• How were the first black holes and stars formed? The first black holes and stars formed 13 billion years ago, an era that is largely hidden from optical telescopes. The SKA will be so sensitive that it will be able to probe this era, learning how the first structures in our universe came into being.

• How do galaxies evolve and what is dark energy? The universe expands at an ever-increasing rate due to dark energy – and nobody knows what it is. The SKA will enable us to learn about dark energy and how galaxies form and evolve over time.

• What generates giant magnetic fields in space? Cosmic magnetism exists through the universe, influencing how objects in space form, age and evolve. Only by using a sensitive radio telescope like the SKA can we detect and learn from the giant magnetic fields out in space.

• Are we alone? The SKA will be able to help detect Earth-like planets and examine the way they are formed. It will also offer the possibility of detecting very faint radio transmissions that might provide evidence of intelligent life among the stars.

• Was Einstein right? Einstein’s theory of general relativity involved predictions for the gravity of black holes – predictions we’ve never been able to test before. By studying pulsars and black holes, we’ll learn more about gravity and the laws of physics.

But undoubtedly the greatest discovery will be the answer to the questions we haven’t even thought of yet. If we are only building the SKA to solve the cosmic mysteries we know about, we aren’t being ambitious enough – or ensuring that the SKA will remain at the forefront of cosmic discovery until the 22nd century.

Along with the impressive scientific discoveries, the SKA promises many benefits beyond astronomy. It will require advancements in a range of technical fields, driving development in green energy, IT and computing systems, and communications technology.

Just as Australian radio astronomy research inspired the development of Wi-Fi technology, the SKA is almost guaranteed to generate spin-offs that will find their way into industrial and consumer electronics. CSIRO is currently developing a revolutionary new form of radio camera (a phased array feed) to be used in the SKA, but it could also be used in medical imaging.

With the possibility of great returns both in scientific discovery and technologies, there is strong global interest in seeing the telescope become reality. A coalition of 70 institutions from 20 countries is seeking the most suitable host for the SKA. The international project has short-listed two regions as potential hosts for the telescope: Australia/New Zealand, with its core in the mid-west of Western Australia; and Africa, with a core site in the Karoo region of South Africa. The international project is now undertaking a thorough review of each location to ensure the outcomes of the SKA are maximised, with a site decision anticipated next year.

With existing astronomy facilities across our nations and the development of cutting-edge radio astronomy technology, Australia and New Zealand offer optimum conditions for the SKA. Existing Australian and New Zealand telescope facilities can be incorporated into the SKA, increasing its capability and reducing its cost.

The Australian and Western Australian governments established the Murchison Radio-Astronomy Observatory (MRO) to allow astronomers to operate telescopes in one of the world’s best locations for astronomy. The MRO is Australia and New Zealand’s proposed core site for the SKA. It is also home to CSIRO’s Australian SKA Pathfinder, a 36-dish telescope that will be the fastest radio survey telescope in the world courtesy of the radio camera technology being developed by the CSIRO.

To connect the thousands of SKA antennae, Australia offers an existing continent-wide fibre-optic network with high capacity links to bid partner New Zealand. The MRO is being equipped with high-capacity fibre-optic cables to link the SKA Pathfinders and ultimately the SKA with supercomputers in Perth and with other SKA partner countries. The Pawsey High Performance Computing Centre for SKA Science in Perth will be used to process and understand observations made at the MRO’s SKA Pathfinder telescopes, and build the foundation for tackling the data challenge of the SKA.

Radio telescopes require radio-quiet environments where radio interference from human activity can’t drown out the faint signals from space. Despite being the focus of significant infrastructure development, Australia’s proposed SKA core site is situated in one of the least populous areas of the world. The MRO is situated in the shire of Murchison, an area the size of The Netherlands with a population of only 110. Likewise the vast, largely empty interior of the Australian continent offers great flexibility in placing SKA remote stations.

Australia and New Zealand’s natural suitability for radio astronomy provides a great location to maximise both the science and non-science benefits of the world’s biggest telescope.

Led by the inter-governmental Australian and New Zealand SKA co­ordination committee, our site bid is currently being developed for submission to the international project this month.

The site decision is currently due in early 2012 and will be made by the SKA governing entity. The first steps towards that entity were taken earlier this year when Australia, China, France, Germany, Italy, The Netherlands, New Zealand, South Africa and the UK established an SKA Founding Board committed to resourcing the pre-construction stage of the SKA. Pre-construction will last from 2012–15 and will deliver a production-ready design for SKA Phase 1 to be built from 2016–20. Over the coming months, additional countries are expected to join the Founding Board, including Canada and India.

The commitment of those countries to support the development of mega-science infrastructure in these challenging financial times attests to the strength of the SKA’s science and broader benefits beyond astronomy.

The SKA is good for the world, and the Australian and New Zealand site is good for the SKA.

Brian Boyle is anzSKA Director.