SKA: a step closer

In my last post I talked about improvements in astronomy (especially radio astronomy) over the past 60 years. Looking to the future, the next big thing in radio astronomy will be the Square Kilometre Array (SKA). Unsurprisingly, it will consist of a square kilometre of collecting area, but rather than be in one single dish (which is a bit impractical from an engineering point of view) it will be made up of lots of smaller dishes spread over a gigantic area. This is a truly huge project which no one country can do alone, so it is being developed by astronomers and engineers from all over the globe. It is planned to be constructed around 2015 and should push the sensitivity of radio astronomy up by another factor of 10 compared to the EVLA and eMERLIN which will be coming online in the next few years.

The eventual location for this huge project has, finally, been narrowed down to shortlist of two: South Africa (and surrounding countries) and Australia (and possibly including New Zealand).
So why are these two the best places on Earth? Well, there are a couple of reasons. First, both of them are in the southern hemisphere at a latitude which lets you look at the most interesting parts of the sky. Not only do you see some of the northern hemisphere but you can easily see the most interesting parts of our galaxy (like the centre) as well as our neighbouring galaxies the LMC and SMC. The second reason is that in other places there are too many people; folks like you and me. Where people live, mobile phones, Wifi networks, TV, radio stations and other sources of radio waves have a tendancy to follow. If you are going to build a stupendously sensitive instrument, you had better put it in a very quiet environment in the same way that big optical telescopes get built a long way from towns and cities that light up the night sky.

Both Australia and South Africa are ideal for the SKA because they have deserts with large areas with low population densities and that isn't likely to change too much in the next 20 years or so. Which will come out as the final site remains to be seen (although not before 2010) and may end up being decided by politicians rather than on the basis of science.

What could come after the SKA? A radio telescope on the far side of the Moon perhaps?

Posted in astro blog by Stuart on Friday 29th Sep 2006 (13:25 BST) | Permalink
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