When it comes to telescopes, many astronomers will tell you that bigger is better. The larger your collecting area, the fainter the astronomical objects you can study. Radio astronomers have longed for a telescope with a full square kilometer of collecting area. (That’s 247 acres!) Now, as it comes closer to reality, they are trying to decide where to put it.
The Square Kilometer Array (SKA) project is an international collaboration with the ambitious goal of building the largest, most sensitive radio telescope by the mid-2020′s.
However, the more sensitive a telescope, the more susceptible it is to interference from human-made radio signals that can ruin astronomical observations. So, not only does the SKA need a large plot of land, it needs a very, very radio-quiet site, as far from people as it is feasible.
When I first began doing research in astronomy, several countries were developing concepts for an SKA-like telescope in their country. China envisioned a whole array of Arecibo-like telescopes in the mountains, and have recently begun building a 500-meter behemoth single-dish in southwestern China.
Australia proposed thousands of spherical antennae called “Luneburg lenses” (which struck me as some kind of large alien mushroom). Today, the SKA is proposed to be an array of thousands of dishes located in either South Africa or Australia, as imagined above. Both countries have poured resources into the project with the hope of being selected as the host country.
I was actually at the South African candidate site in the Karoo when the time-line for site selection was officially announced.
In recent years, both desolate sites have been scanned intensely for human-made interference, and both projects have built pathfinder arrays as a “sample” of what the SKA dishes might look like, such as the Karoo Array Telescope above.
In addition, the governments have made astronomy a national priority, setting up laws protecting the radio-quiet sites in the Karoo and the Outback and funding initiatives to train more students and post-docs in radio astronomy. All of this effort will come to a head when the SKA collaboration chooses a winning site in just seven short months in February 2012.
Having worked with astronomical data from both sites, I can say that both are wonderfully suited for the task of being radio-quiet. The site selection will include many other factors, such as infrastructure, or how well each country can support a large research station in the middle of an empty desert.
We’ll all have to wait patiently as expert panels pore over every bit of information submitted by each country in the next few months. Nine countries have already pledged their support in building the array, though my home country of the United States is noticeably absent. (The recent Decadal Review in Astronomy was not favorable towards it, though it supported continuing pathfinder efforts with the SKA in mind.)
It is easy to get mired in the politics and discussions surrounding this huge and ambitious project. However, it helps to step back and marvel at the ingenuity and drive of those working to make such an astronomical dream come to light. With site selection in hand in early 2012, I expect we’ll start to see some impressive development towards making the SKA a reality.
Images: Top – Artist’s conception of the completed SKA. Credit - SPDO/TDP/DRAO/Swinburne Astronomy Productions. Middle – 5 of the 7 Karoo Array Telescope antennas on a rare, cloudy day in the Karoo. Creidt – N. Gugliucci.