A few weeks ago while in Australia, I had the opportunity to return to a pretty special place: the Murchison Radio-astronomy Observatory or MRO.
Why is it so special? Well for starters, the site happens to be sitting on some of the oldest ground on the planet, with rocks nearby dated at 4.3 billion years old. (the oldest dated at 4.7 billion years were found just a few hundred kilometres away) This is an old weathered land, and until 10 years ago, there was only red dirt here. Not only this, but in some years the MRO will be home to the Australian component of the largest scientific instrument on the planet: the Square Kilometre Array (SKA) radio telescope.
But also, the MRO sits in the middle of the Australian outback in a remote area of Western Australia. And when I say remote I mean remote. To get there, you first need to get to Geraldton, the nearby town equipped with an airport.
Nearby has a different meaning for Australians: from there, it still takes 5h to get to the observatory, and for the last 3h of the journey, there’s no road, just a dirt track through an arid, mostly flat landscape of shrubs and small trees under a sizzling sun as far as the eye can see. In those 3h, we saw about 3 vehicles. Needless to say, you lose phone signal long before that. Punch a tyre or get ill and you’re in serious trouble.
So why go through all this trouble and put an observatory so far out from existing infrastructure? Well the key is the word radio. Optical telescopes need to get away from cities to avoid light pollution swamping out the faint photons coming from space. Radio-telescopes must get away from radio-pollution for the same reasons, so they can detect the faint radio signals emitted by cosmic objects.
And what causes radio-pollution? Pretty much every electronic equipment, and in particular phones, cameras, and even cars, hence the need to get away from civilisation as much as possible to conduct their crucial observations. This makes the MRO pretty special, and indeed the observatory is not open to the public to preserve the “quietness” of the site, which sits in the middle of a 150km radio-quietness zone. Switch a mobile phone on inside that zone and the telescopes will pick it up, swamping the faint signals coming in from space. So we were pretty lucky to get special approval from CSIRO * – who runs the site – to visit.
The site is currently home to two state-of-the-art radio telescopes that are precursors to the SKA: ASKAP and the MWA (a third precursor, MeerKAT, is being built in South Africa). Both ASKAP and MWA are arrays of antennas that work collectively to receive radio signals which are then digitally assembled by a supercomputer to simulate a giant telescope whose surface would be equivalent to all the antennas put together.
ASKAP is a 36-antenna array, with each antenna’s main reflector ( a tech term for dish) measuring 12m across. It is currently undergoing commissioning, which means the team is prepping it ahead of full science operations which should start in 2016. It’s being equipped with some pretty fancy tech too. Each antenna will host a Phased Array Feed or PAF, a novel instrument developed at CSIRO that is basically a radio CCD, with a much larger field-of-view than previously possible allowing to scan the sky at radio wavelengths much faster.
MWA’s another interesting telescope. If you’re a fan of sci-fi and Stargate SG-1, its antennas, akin to metallic spiders, look like replicators. There’s 2048 of them spread around on 128 tiles (16 per tile). The cool bit: they have no moving parts. So how do they point at objects? It’s all done electronically. The result? A cheap-to-build telescope capable of real science.
But there’s a new kid on the MRO block. An MWA tile has been refitted with 16 prototype antennas of the future SKA as part of SKA pre-construction activities. In a way, they’re the first 16 of what in decade should be 250,000 similar antennas in the Australian outback (one of 3 initial SKA instruments). Seeing them was a pretty special thing for all the engineers and scientists involved in the project on our tour, as it a gave a sense that what we’re all working towards is becoming reality.
From there, it wasn’t hard to imagine a sea of such antennas in the Australian outback, peacefully listening to the faint signals coming from the far reaches of the Universe in this quiet and remote corner of our planet, tucked away from the radio noise of our civilisation!
*CSIRO, The Commonwealth Scientific and Industrial Research Organisation is Australia’s national science agency.