Astronomy Now Home
Home Magazine Resources Store

On Sale Now!



The September 2014 issue of Astronomy Now is on sale! Order direct from our store (free 1st class post & to UK addresses). The Astronomy Now iPad/iPhone editions are now available worldwide on the App Store.



Top Stories



Earthshine used to test life detection method
...By imagining the Earth as an exoplanet, scientists observing our planet's reflected light on the Moon with ESO's Very Large Telescope have demonstrated a way to detect life on other worlds...
  READ MORE

Solid buckyballs discovered in space
...Astronomers using NASA’s Spitzer Space Telescope have detected a particular type of molecule, given the nickname “buckyball”, in a solid form for the first time...
  READ MORE

Steamy water-world gets the Hubble treatment
...Hubble Space Telescope observations of a 7 Earth-mass planet find an unusual water-rich world swathed in a thick, steamy atmosphere...
  READ MORE








South Africa and Australia share SKA spoils
BY KEITH COOPER
ASTRONOMY NOW
Posted: 24 May 2012


Bookmark and Share

SKA Dishes by Night An artist's impression of some of the SKA's 15-metre dishes underneath the Milky Way. Image: SPDO/TDP/DRAO/Swinburne Astronomy Productions.

The location of the Square Kilometre Array (SKA) - a giant collection of radio dishes, arrays and antennae that will combine to form the largest telescope ever built - has surprisingly been awarded to both countries competing to host it, splitting the SKA not only over two countries but two continents.

"The SKA will be one of the top global science projects of the twenty-first century," says Dr Richard Schilizzi, Director of the SKA's Programme Development Office at the University of Manchester. It will revolutionise radio astronomy, with twenty percent of the telescopes to be found within a square kilometre in the Karoo region of South Africa. Other telescopes spreading into eight other African nations as well as South Africa's rival to host the SKA, Australia, will combine with that central square kilometre to form one giant telescope that will achieve an angular resolution of 0.1 arcseconds.

The science and technology of the SKA will be formidable:

  • To process all the data from the SKA, computers able to perform 1018 operations per second (an exaflop) will be required
  • The SKA will be divided up into a forest of 15-metre diameter radio dishes and high and low frequency aperture arrays
  • The SKA will operate across a range of frequencies, from as low as 70MHz to as high as 10 GHz
  • The SKA will probe the Dark Ages, the mysterious era between the epoch of recombination that emitted the cosmic microwave background and the rise of galaxies
  • Other science studies will include investigating the formation and evolution of galaxies and how large scale structure in the Universe has been affected by dark energy, as well as studying pulsars and black holes, investigating the origin of cosmic magnetism and searching for SETI signals
  • The announcement that both South Africa and Australia, who were competing against each other to host the SKA, is a surprising one borne out of the wish to maximise investments already made in both countries, say the SKA Organisation, a multi-national consortium of countries including the UK. What makes their decision slightly controversial is that the organisation's own Site Advisory Committee had ruled that while both bids were excellent, South Africa had the edge overall after considering criteria such as levels of radio interference and long term sustainability of a radio quiet zone, the physical characteristics of the site, long distance data network connectivity, operating and infrastructure costs as well as the political and working environment. However, taking into account that South Africa and Australia, with whom South Africa had been competing, have invested large sums already by building two precursor telescopes - MeerKAT (the Karoo Radio Telescope) in South Africa and ASKAP (the Australian SKA Pathfinder) the advisory committee decided that being inclusive was the best way forward. While the split decision will incur extra cost for the 2.5 billion dollar radio telescope, it is hoped that it will increase the scientific returns, particularly during the project's first phase.

    South Africa's Minister for Science and technology, Naledi Pandor, expressed some surprise at the decision given that the advisory committee had recommended South African bid as the best one on the table.

    "[This] is an unexpected decision given the search for a single site," she said in a statement. "We had hoped the unambiguous recommendation of the SSAC would be accepted as the most sound scientific outcome. However, in order to be inclusive the SKA organisation has agreed to consider constructing one of the three SKA receiver components in Australia. We accept the compromise in the interest of science and as acknowledgement of the sterling work done by our scientists and the excellent SKA project team."

    Contrasting views came from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Sydney. "This is a fantastic outcome for Australia and for international science," says CSIRO's Chief executive, Dr Megan Clark.

    Wherever the SKA was to be built, British scientists, as part of the SKA Organisation, were always going to have a hand in the science. "The decision for a dual site maximises use of investments already made in both locations," says Britain's Minister for Universities and Science, David Willets. "It also ensures that all the great experience already gained can be put to best use designing and delivering the next phase of the project, in which UK scientists will play a key role."

    Phase I will begin construction in 2019, consisting of a mix of 15 metre radio dishes initially built in South Africa and combined with MeerKAT, followed up by more dishes built and combined with ASKAP in Western Australia's remote Murchison Radio Observatory 600 kilometres north-east of Perth. Mid-frequency arrays will be constructed in South Africa, while low frequency arrays will be assembled purely in Australia. As a result, each country will contribute different science: Australia (and its partner, New Zealand) will specialise in big picture large scale surveys, while the South African contribution, shared by its partners Botswana, Ghana, Kenya, Madagascar, Mauritius, Mozambique, Namibia and Zambia, will focus on targeted observations.

    Phase II will follow several years after completion of Phase I, taking what has been learned from the initial phase and applying it to the South African array to increase the sensitivity. However, funding has not yet been guaranteed for phase II, design studies are yet to be implemented and it remains to be seen how the decision to split the SKA will affect the long-term planning of the telescope.

    To learn more about the SKA, visit the project's website at www.skatelescope.org.

    The Planets
    From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
     GET YOUR COPY

    Hubble Reborn
    Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
     GET YOUR COPY

    3D Universe
    Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
     GET YOUR COPY


    HOME | NEWS ARCHIVE | MAGAZINE | SOLAR SYSTEM | SKY CHART | RESOURCES | STORE | SPACEFLIGHT NOW

    © 2014 Pole Star Publications Ltd.