Posted on behalf of Gayathri Vaidyanathan.
South African astronomers operating some of the world’s most sensitive telescopes say that their research will not be affected by the resumption of oil and gas exploration in the Karoo Basin, the country’s astronomy hub.
South Africa lifted its moratorium on shale-gas exploration last week, bringing the nation closer to approving hydraulic fracturing, or ‘fracking’, a controversial technique in which water, sand and chemicals are injected at high pressures to extract gas and oil. A report published yesterday by a working group of policy-makers, astronomers, geologists and others found that energy development and astronomical research in the Karoo are equally important and can co-exist.
Any potential effects on telescopes will be mitigated by careful study and collaboration between the Department of Science and Technology (DST) and the Department of Mineral Resources, the report states. If impacts on the telescopes cannot be mitigated at close range, the science minister has the power to restrict or prohibit exploration and drilling under the Astronomy Geographic Advantage Act of 2007.
“Although not clearly defined at this very early stage in the process, it is suggested that the impacts of shale gas exploration and production on radio astronomy can be managed to accommodate both, though it is expected that there will be some areas where it may not be possible to make provision for both activities, in which case petroleum exploration and production activities will be precluded,” the report states.
South Africa has an estimated 13.7 trillion cubic metres of technically recoverable shale-gas reserves, making it the fifth largest in the world, according to the US Energy Information Administration.
Much of it is contained in the Karoo, which is to be the site of the Square Kilometre Array (SKA), the world’s largest radio telescope, which will probe the origins and evolution of stars, study dark matter and other phenomena (See ‘Winners all round in telescope bid’). The Southern Hemisphere’s largest optical telescope, the Southern African Large Telescope (SALT), is also located in the Karoo. The region was chosen in part because it has minimal interference from human-generated radio waves and pollution; there is only the occasional sheep farm in the arid region (See ‘Astronomy in South Africa: The long shot‘).
So, when Royal Dutch Shell applied for a licence to explore for shale gas in a 90,000-square-kilometre area that overlaps parts of the SKA area, scientists started worrying (See ‘Mining plans pose threat to South African astronomy site‘). Vehicles and equipment associated with oil and gas activity generate broadband electromagnetic waves that may interfere with the SKA. Light pollution from the flaring of natural gas and air emissions could affect the SALT. The seismic tremors caused by fracking could also disturb the telescopes.
A SKA scientist participated in the working group and prepared Annex D of the report, which examines the extent of electromagnetic interference that can be expected from fracking machinery. On the basis of rough calculations, the report recommends that fracking should not happen within a 30-kilometre buffer zone. Any activity proposed within 50 kilometres of a SKA station should be carefully analysed for impact before it is allowed, the report states.
Seismic activity is not a major concern at this time, according to Adrian Triplady, the SKA site bid manager for South Africa. But the telescope consortium will keep a close eye on developments.
The SKA consortium is also comfortable with the “assurances that nothing will be done that would compromise the operation of the SKA,” says Jo Bowler, interim outreach officer at the Office of the SKA Organisation in Manchester, UK.