Astronomy has big ambitions. Soon its new telescopes will stretch across continentsby Pedro Ferreira / May 4, 2009 / Leave a comment
A computer simulation of SKA focal plane arrays and small dishes, 2008
It’s like a page torn from a Dan Dare comic strip, where the undeveloped world meets the ultra future: a barren landscape of rock and bush, peppered with radio antennae so sophisticated they have yet to be invented. But it won’t be on another planet, or involve space travel. Rather, it will be the world’s most sophisticated telescope—a series of hundreds of antennae stretching across thousands of kilometres of Australian or southern African desert.
The planned square kilometre array, or SKA, is a giant camcorder scanning the sky in all directions to pick out every galaxy visible on the earth’s cosmic horizon. Its many separate dishes will simulate a single giant telescope, with a central “collecting area” of one square kilometre capable of capturing electromagnetic waves from the outer reaches of space.
The current generation of telescopes pick up only about 5 per cent of the universe’s energy and matter; the vast majority remains invisible or dark. Cosmologists think that unravelling this dark world will allow us to understand both the history of the universe and the formation of galaxies such our own. A range of new projects aim to help to solve this central problem of modern cosmology, namely establishing what, and where, dark matter and energy is. The SKA, originally conceived in the 1990s by a group of scientists from 19 countries, has become the poster child for such “big astronomy.” Today’s telescopes can provide different windows on the universe, but not a single picture. The SKA, if built, could turn this incomplete vision into a new map of the universe.
Similar projects include optical telescopes with collecting areas around a hundred times larger than today’s; and (under discussion at the European Space Agency and Nasa) a new wave of scientific satellites armed with new instruments capable of looking more accurately and more deeply into space. The hope is that this image of the entire universe will allow scientists to reconstruct how its different building blocks—from individual planets to whole galaxies—assembled into one coherent whole. This in turn, should help to tease out the nature of dark matter and energy itself.
At present the SKA remains a theoretical venture; getting it up and running means solving a series of daunting technical problems.…