What’s the SKA, you may ask? It’s nothing to do with a Madness reunion tour, entertaining as that may be. It’s a proposal for the biggest radio telescope – or, more precisely, collection of radio telescopes – the world has ever seen.

The first radio waves shown to be coming from somewhere outside Earth were detected in the early 1930s, according to Wikipedia, but radio astronomy really got going in the early 1950s. Along the way, astronomers have found all manner of things that haven’t been seen with optical telescopes; indeed, a huge fraction of what we’ve learned about the universe since has come from radio astronomy. The major experimental evidence for the Big Bang – the Cosmic microwave background radiation – was first observed through radio telescopes, though later studied in much more detail from a satellite-based radio observatory. Pulsars – the rapidly rotating remnants of exploded giant stars – were first discovered by radio astronomy, which led to the discovery of the first planets outside our solar system.

Astronomers have a new set of challenges, for which they’d like a new, bigger, set of telescopes. The SKA science program lists a number of them. For example, they hope that the new telescope array, with its extra sensitivity, will be able to detect a fair fraction of the pulsars in our galaxy. Amongst those pulsars, they hope to find one that has a black hole as a companion. A black hole is the remnant of an even bigger star than a pulsar, after its spectacular death in a supernova. According to theory, a black hole is such a big lump of matter that it compresses itself down into an infinitesimally small point. Such a pair of objects, when the array finds them, would provide the sternest test for Einstein’s theory of general relativity yet known. The SKA will also help to provide more evidence on whether we’re alone in the universe or not. It’ll be capable of examining the dust clouds around newly forming stars in great detail, giving a much better idea of how planets form. And, finally, if ET just happens to be watching TV on a planet located in a nearby solar system, the SKA would be capable of picking up their equivalent of Home and Away reruns.

The SKA itself won’t be one big telescope, like the enormous Arecibo dish. Instead, it will be a very large collection of small receivers, though it’s not yet clear whether those small receivers will look like little satellite dishes, little satellite dishes with mesh backing, or an entirely different design which “steers” the array electronically, without moving the antennas at all! Working together, however, the SKA’s antennas will cover an area of roughly a square kilometre – hence, Square Kilometre Array.

There won’t be a a single block of these things. They’ll be split up into groups and placed in different locations, and the further away the better (essentially). With a technique called interferometry, if you have two telescopes in different locations, or in this case two collections of telescopes, you can theoretically get the same detail as if you had a telescope the same size as the distance between them! Hence, the interest in getting New Zealand in on the game; with most of the array in Western Australia and a bit of it in New Zealand, the radio astronomers can synthesize a telescope, not only with enormous sensitivity, but with the abiility to pick out very small details.

After evaluating sites in China, the USA, and South America, the SKA project – an international consortium of which Australia was a founding member – is currently deciding between the Australian bid and a South African one; we may well be the favourites given that the South African bid requires spreading the telescope over a number of different countries of varying levels of economic development and stability. While it would be mildly nice if it were built in Australia, in all honesty, in a lot of ways it’s probably more important that we’re on the consortium, and thus Aussie astronomers will get observation time on the telescope.

All up, the array will probably cost around 3 billion dollars. It’s not a cheap way to find answers to things that will, in all likelihood, have little Earthly application. But given the costs are spread across pretty much the entire developed world, not to mention China and India, I reckon it’s very good value; frankly, it’s the kind of big, fundamental science project the world does too little of. Are you prepared to spend what will come to less than a dollar per year to understand more about the fundamentals of the universe we inhabit?