Date: May 25, 2011
Title: The Square Kilometre Array for Australia
Podcaster: The Ordinary Guy from the Brains Matter podcast
Organization: Brains Matter – http://www.brainsmatter.com
Description: Many of us have heard about the Square Kilometre Array project. What is it? Why is it useful? The Ordinary Guy from the Brains Matter podcast talks to Dr Michael Brown from Monash University who has had done extensive work with the Australian Square Kilometre Array Pathfinder project to learn more about why Australia would be a great location for the SKA.
Bio: The Brains Matter podcast has been producing and communicating science stories and interviews since September 2006. The show is based out of Melbourne, Australia, and takes an everyday person’s perspective of science in easy-to-understand language.
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Transcript:
Hello everyone, I’m the Ordinary Guy from the Brains Matter podcast (www.brainsmatter.com) Welcome to the 25th of May episode of the 365 days of astronomy podcast. On today’s episode, I talk to Dr Michael Brown about the Square Kilometre Array, and why Australia would make a perfect location for it.
Ordinary Guy: So how’s it going to work?
Dr Michael Brown: It’s going to be a pretty amazing piece of technology. So the telescope itself is going to be what we call an interferometer, so rather than building one single dish that’s a square kilometre in size, like a kilometre in diameter…
OG: That would be very difficult to construct, of course!
MB: It would be very, very difficult to construct and even harder to move around. So instead of building one single dish, what’s going to happen is that there’s going to be an array of smaller dishes which are connected together electronically to behave like a single giant telescope. There are also advantages in performance, so one thing one can do with telescopes is the sort of resolution – the ability for us to see the fine detail in an objects defined by the diameter of the telescope – and what one can do with an array of smaller telescopes is one can spread them out over a very large area, so rather than sort of spreading the telescopes over just one kilometre in diameter, one could spread them out over tens or hundreds and even have some outrigger telescopes a thousand kilometres away, and get the ability to see fine detail that you would get from a telescope that is a thousand kilometres in diameter. So while the Square Kilometre Array, the intention is to have a square kilometre of collecting area, the ability to collect light equivalent to a single dish that’s a square kilometre in size, we can get finer angular resolutions in such a telescope we can see finer detail in celestial objects by spreading our array of telescopes over a very large area.
OG: So is the intent at this stage to put outlier telescopes belonging to the SKA, or is it to use other telescopes around the world that already exist as part of that network?
MB: The intention is to actually have new telescopes, part of the SKA by design from the word go feeding into this array. There has certainly been a history of connecting various telescopes together in this fashion to obtain very high angular resolution, for example, many times people have connected Parkes, the dish, with Tidbinbilla near Canberra to build such a sort of telescope, but the SKA, it’s going to be designed from the word go to sort of do this. And there’s certain ways you can spread the antennas around to get an optimal image. Certainly, just having two telescopes a thousand kilometres apart gives you some of the capabilities of a thousand kilometre diameter telescope, but it doesn’t give you all of them. Nothing’s for free, and there are some fairly severe penalties that you pay by doing that. But the SKA’s going to move, have the telescopes arranged in an optimal pattern so we get as close to that thousand kilometre telescope without having to build a thousand kilometre dish.
OG: So why is there a need for the Square Kilometre Array?
MB: So the Square Kilometre Array introduces a lot of advantages over previous telescopes in terms of its ability to get fine angular detail, and it’s sensitivity. And the sensitivity really is a massive increase on what we have had available to us previously.
OG: And in terms of the SKA project itself, do you want to go through a little bit of the background of that, because as I understand it, there have been several countries who have been vying for the project to be put into their country, and it’s almost – given that it’s timely that it’s been Eurovision – for those people, especially in Europe and I know it’s quite big in Australia – it’s not that dissimilar is it, in the sense that people are putting up their candidacy for it and there’s been people knocked out and finalists and so on?
MB: Yeah, there has been. So what happened was that instead of a song for Europe, what’s happened is astronomers have thought of a radio telescope for the world and there was a recognition that if astronomers around the world pulled their resources together, their ideas together, their technology together, they could build a much more powerful facility than if they were operating in a piece-meal fashion. And so this is where the concept of the Square Kilometre Array began to take place. Radio astronomers around the world have been very enthused about this, and there’s a lot of great science that can be done with this. They’ve then been discussing where to locate this telescope, where the optimal site is, and there were four candidates originally – Chile, China, South Africa, and Australia. And there was a lot of site testing done to see if they were suitable sites…
OG: What constitutes a suitable site? I’m assuming low radio interference from local cities and things like that ..
MB: Yeah, exactly. A radio telescope, while it wouldn’t be pointed at a nearby city, the emissions, the radio stations, the mobile phones, the computers, the electronics – all emit radio waves and some of those do get detected by radio telescopes, so we want to position the radio telescope as far from those sources of interference as possible. And then there’s also other figures of merit for the site, for instance, the Chilean site had quite a few things going for it but it was quite remote, Chile didn’t have a history in radio astronomy so there wasn’t quite the support there as well, and also the shape of the county meant that you couldn’t quite distribute the antennas in the optimal way and that was one of the reasons it got knocked out. For similar reasons China got knocked out as well, and also with China of course there’s issues with radio interference as well – it’s a big country and so there’s a lot of people there and there’s going to be an increasing amount of radio interference. So at the moment the choice is between South Africa and Australia, and a final decision is going to happen in the next year or two on which of those sites does win the contest for radio telescope for the world.
OG: So what are the main advantages of having it in Australia compared to say, South Africa, or is that a pretty tough call to make?
MB: Look, there are … each of the sites have their merits. The Australian one has some advantages relative to the South African one. One is that the population density is extremely low.
OG: It’s going to be, as you mentioned before, near where the current Pathfinder is, which is the West Australian desert.
MB: Yep.
OG: Having been out there, it’s miles and miles of flat land of nothing
MB: Yes, I believe it’s in a region that’s about the size of Belgium, with a permanent population of about 200 people. So in terms of radio interference from people getting mobile phones and computers etc. that’s somewhat of an advantage, whereas the population density of South Africa is somewhat higher, though of course South Africa has its famous deserts as well. And so that’s one advantage. And of course Australia has a longer tradition of radio astronomy than South Africa, although South Africa has been doing a very impressive job of building up its radio astronomy credentials and has built up an amazing community there in the past decade or so. So they’re both very viable contenders.
OG: What is your initial prediction at this point for what the announcement might be – or is it too close to call?
MB: I think it’s still too close to call, although I have my fingers crossed and I hope that Australia is in the lead when it comes to this particular race.
OG: So if there was someone out there listening to this podcast at the moment and you wanted to sell the Australian position to them, what would you say?
MB: Well, I would say that the Australian site in many respects, it has advantages over the South African one. With the telescope sited in Australia, it’s a billion dollar project – the full SKA. And so it’s going to bring tremendous investment in science to Australia, tremendous investment in various technologies, for instance, the Square Kilometre Array is going to produce about two and a half gigabytes – actually it’s going to produce many gigabytes of data every single second and that data has to be processed with a supercomputer and in fact the data has to be transported from the Australian desert to a supercomputer in Perth where the data has to be processed and then that processed data has to be shipped to astronomers around the world. So there’s a tremendous investment in technology there. And it’s not just investment in technology from the Australian taxpayer, it’s a multinational effort. There’s going to be tremendous opportunity for Australian scientists to collaborate with their international partners and it’s not just going to be Australian astronomers doing that, it’s going to be people who are working in engineering, in computer science, a whole range of technologies. So it’s going to be a great investment in Australian science and Australian technology that should have benefits that go on for many decades.
OG: OK well Dr Michael Brown, I’d like to thank you for your time today
MB: It’s been a pleasure.
Thanks for listening – and if you want to hear the full version of this interview, head on over to www.brainsmatter.com.
Bye for now!
End of podcast:
365 Days of Astronomy
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