At the dusty fuel station on Carnarvon’s deserted main road, Neville quizzed me on my car’s branding. He wanted to know what Too Much Too Many was all about. I explained, and he chuckled as he replied, “You’re worried about population growth, I get that, but why visit Carnarvon? Hardly anyone lives here!”
Carnarvon is situated in the massive Northern Cape, South Africa’s largest and least populated province. Only 1.1 million people live in the Northern Cape and few regions of the world remain as sparsely populated. Japan, by comparison, has a smaller land mass and a population of 120 million people.
I was on my way to the construction site of the Square Kilometre Array (SKA), 80 km out of Carnarvon. The SKA, which will rely on this remoteness to function, will become the world’s most powerful telescope.
Optical and radio telescopes
The more widely understood telescope is the optical telescope, which uses light waves to make images. We use optical telescopes at night, when it is darker. The SKA will be a radio telescope, creating images from faint radio signals emitted elsewhere in the universe. Just as optical telescopes need to be located away from artificial light sources, radio telescopes need to be located away from manmade radio waves, known as radio frequency interference or RFI.
After leaving Carnarvon and driving along an endless corrugated dirt road, a sign warned, “You are now entering the Radio Astronomy Protected Area. This is a RADIO QUIET ZONE. Please switch off cell phones and electronic devices.” I was in an area where the law restricts activities causing RFI. Astonishingly, making a cell phone call could seriously damage SKA equipment.
After parking my car, an engineer told me that soon petrol vehicles, like mine, would also be banned from the site. Unlike diesel vehicles, petrol vehicles use spark plugs to start their engines. Spark plugs are another source of RFI.
I visited a building half hidden underground, the future home of SKA computers. Project Director, Dr Bennie Fanaroff, explained that the SKA’s computers were like all computers and generate RFI. The SKA's computers must therefore be housed underground, in rooms encased in metal, to prevent the RFI impacting the SKA.
It is not possible to completely escape manmade RFI anywhere in today’s world. Sources of RFI, even at the remote SKA site, include satellites passing overhead and even the giant metal walls of the site’s assembly hangers, should they move in the wind. The site is, however, about as radio quiet as is possible, given the ubiquity of electronic equipment.
The SKA & its benefits
To the untrained eye radio telescopes look like oversized satellite TV dishes. One dish can operate alone, or as part of an array of many dishes. Construction of the SKA should be completed by 2030, when there will be so many dishes that their combined surface area, rather than the very much larger site footprint, will amount to one square kilometre, hence the name “Square Kilometre Array”.
I spent some time at the seven dish engineering prototype telescope, KAT-7, which is already operating. Adjacent to KAT-7 will be the next phase, the 64 dish MeerKAT. Its foundations were completed on the day of my visit.
MeerKAT will form 25% of SKA Phase One and will alone become the most sensitive radio telescope in the world. The fully completed SKA will be 50 times more powerful than any existing radio telescope.
Astronomers hope the SKA will help them map the structure of the universe, understand dark energy and discover how stars and galaxies were formed. But SKA benefits will go beyond astronomy.
The quantity of data which the SKA must process will be so vast that new computing technologies will have to be developed to cope. Dr Fanaroff explained that every day the SKA will produce data equivalent to, “streaming 1 billion high definition movies” and that so much data would require computing technology, “nearly 100 times faster than the current fastest computer in the world”.
We already have radio astronomy to thank for the development of Wi-Fi, it seems likely that other computing advances will follow.
The importance of wilderness
Although a population explosion in the Northern Cape is far from likely, there are other population pressures which can impact the SKA. National and international population and consumption growth will lead to increasing energy demand. The Northern Cape is suitable for both wind energy and solar plants and is thought to hold rich shale gas reserves. The construction of energy infrastructure for any of these activities would generate RFI which could negatively impact the SKA. Astronomers are lucky energy companies didn’t beat them to the area.
Legislation is in place to protect the radio quiet area around the SKA but, as energy demand rises, so will pressure to tap into the Northern Cape’s resources. It remains to be seen whether the interests of astronomy will continue to trump those of people demanding electricity.
South Africa retains some sparsely populated areas. As we have seen, the worth of these areas is not restricted to wilderness merely for the sake of wilderness. European astronomer, Russell Johnston, explained that, "the unpopulated Northern Cape is one of the few places left on earth where we can do this. There's no area left in Europe, without man-made radio interference, which is large enough to host something like the SKA".
We all know population growth can negatively impact human living conditions and practically guarantees habitat loss, but what is less well recognised is that it can also restrict scientific endeavours like the SKA. Who knows, the SKA might even locate a second habitable planet, and that could come in very useful, given population and consumption growth means we continue to over exploit this one.