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Wednesday, December 21, 2011

The Experiment of the Century!


The experiment of the century is aiming for the outer precincts of the unknown universe with a radio telescope of colossal proportions, developed by an international consortium of scientists. The massive network of telescopes is known as the "Square Kilometre Array" (SKA).

KAT-7 The seven-dish prototype interferometer array in the Karoo. Picture credit: SKA Africa
The SKA is currently in development and scheduled to be built in the southern hemisphere, in either the Northern Cape of South Africa, or in Western Australia. The chosen sites in both countries is where the view of our own galaxy, the Milky Way, is best and radio interference least. 

The splendid beauty of the Milky Way, even when seen with the naked eye, without a telescope, is hard to describe to people who have never witnessed its awesome magnificence. This is one of the reasons why I’m finding it very difficulty to leave Southern Africa permanently, as I’m not quite sure how I’ll adapt to surroundings where such tranquil and soul-soothing natural splendours do not exist. Moving to Australia is, for several personal reasons, totally out of the question!

The SKA-project promises to answer some of the most fundamental questions about the evolution of the universe, including the emergence of the first stars and galaxies. It will be so sensitive that it will be able to detect an airport radar on a planet 50 light years away. In other words, it will be capable of probing back into time, to places that existed billions of years ago… Truly astronomical, I tell you!

The central SKA computer will, among other mind-blowing capabilities, have the processing power of about 1 billion PC’s. More interesting facts and figures can be viewed here. 

Note: The links to all relevant sources in this article are repeated at the end of this posting, so please continue reading at your own leisure!

Although the total collecting area of the SKA will be one square kilometre, it will develop into the world’s single largest and most powerful radio telescope ever constructed - by utilizing 3000 dish-antennas, each about 15 metres wide - as well as two other types of radio wave receptors, known as aperture array antennas. The antennas will be arranged in five spiral arms extending to distances of at least 3000 kilometers from the centre of the array.

The following artist’s impression of what the central core site in the Karoo will eventually look like is nowhere near realistic, as it does not portray any site buildings, access roads, or the huge tarmac areas around the dish clusters. Bear in mind also that each separate antenna-dish is a sizeable engineering project in its own right.



Above image was sourced from the public domain.

 Here is a more realistic artist’s impression, created by columnist, Ivo Vegter:

The above image were sourced from a posting on dailymaverick.co.za

The SKA is a global collaboration of 20 countries, initially conceived in the year 1991. Four sites were initially proposed in South Africa, Australia, Argentina and China, but after considerable site evaluation surveys, Argentina and China were dropped.

A Race between South Africa and Australia

A race has been on for some time now between the two short-listed countries, South Africa and Australia, to determine which country will be hosting the core SKA site. The final decision will apparently be made sometime in April 2012.  Jodrell Bank Observatory, near Manchester in the UK, was chosen in April 2011 to be the location for the SKA Project Office.

Although political and economic factors will obviously also play a role, the selection-process will focus on the best possible operating environment for the telescope.

The following are some of the criteria that will be taken into account:
  • Radio frequency interference from mobile phones, TVs, radios and other electrical devices.
  • The characteristics of the ionosphere (the upper part of the Earth’s atmosphere) and the troposphere (the lower part of the Earth’s atmosphere).
  • Physical characteristics of the site including climate and subsurface temperatures.
  • Connectivity across the vast extent of the telescope itself as well as to communications networks for worldwide distribution of data produced by the SKA.
  • Infrastructure costs, including power supply and distribution.
  • Operations and maintenance costs.
  • The long term sustainability of the site as a radio quiet zone.  [Source]

In Australia, the core site is located at Boolardy 26°59′S 116°32′E in Western Australia 315 km north-east of Geraldton, on a flat desert-like plain at an elevation of about 460 metres. The most distant stations will be located in New Zealand.

In South Africa, the core site is located at 30°43′16.068″S 21°24′40.068″E at an elevation of about 1000 metres in the Karoo area of the arid Northern Cape Province, about 75 km north-west of Carnarvon, with distant stations in Ghana, Kenya, Madagascar, and Mauritius. 

South Africa and Mauritius have already agreed to jointly construct a low-frequency array telescope in preparation for the Square Kilometre Array (SKA) bid.

The current site in the Karoo is also the location for the South African MeerKAT project which, when finally completed, will consist of an array of 64 - 13.5m diameter antenna dishes. Although a seven-dish engineering and science testbed instrument for MeerKAT (known as KAT-7), is already fully functional, the entire project is scheduled for completion sometime in 2015, or maybe 2016 -- (This Is Africa, remember!)
[Source]

The Australians have similar projects underway, respectively called the Australian SKA Pathfinder (ASKAP), and the Murchison Widefield Array (MWA). The A$100 million ASKAP project will consist of a telescope array of 36, 12m antenna dishes, and is expected to be to be completed by 2013.
[Source]

The photograph below shows an aerial view of the South African KAT-7 precursor array, located outside Carnarvon. The site offices and vehicles in the picture give a general idea of the size of these antenna dishes.
 

Above image was sourced from the public domain.

With a budget of €1.5 billion (about R16 billion), construction of the SKA is scheduled to begin in 2016 for initial observations by 2019 and full operation by 2024. The funding will come from many international funding agencies. Preliminary expectations are that Europe, the United States and the rest of the world will each contribute a third of the project's funding.

Australia has already spent more than $400 million developing its radio astronomy infrastructure since 2006, including $150 million on projects directly related to the SKA. [Source]

Africa’s bid, the development impact, money spent, benefits to the economy – and so forth, can be viewed here, on a SA Government Information website.

In 2010, concerns were raised over increased radio interference at the South African site due to an application by Royal Dutch Shell to explore the Karoo for shale gas using hydraulic fracturing. [Source]  Hmmm, and I thought all the howling about the Karoo fracking business was about saving the water-poor and ecologically sensitive Karoo region – [see older posting : Stop Fracking in the Karoo].


The Astronomy Geographic Advantage Act

This rather extraordinary Act was passed in South Africa in 2007. It outlaws certain radio related activities in areas that are uniquely suited for optical and radio astronomy – (also known as astronomy advantage areas).  This Act has already declared the entire Northern Cape Province, with the exception of the Sol Plaatje Municipality (Kimberley) as an astronomy advantage area with strict regulations on radio frequency interference and 12.5 hectares around the core SKA site protected as a radio astronomy reserve. [Source

Furthermore, the stipulations of this Act (Chapter 5) permits the government to acquire land included in any astronomy advantage area, by -

  • (a) purchasing the land, property or right;
  • (b) exchanging the land, property or right for other land, property or rights; or
  • (c) expropriating the land, property or right in accordance with the Expropriation Act, 1975 (Act No. 63 of 1975), subject to section 25 of the Constitution, if no agreement is reached with the owner or the holder of the right.

List of external sources consulted in preparation for this posting:


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