This is part of our Road Trip 2017 summer series “The Smartest Stuff,” about how innovators are thinking up new ways to make you — and the world around you — smarter.
There are few places in the world that can accommodate a radio telescope. It has what seems to be conflicting needs. The area has to be far enough from human habitation to avoid radio interference, yet close enough that it can be supported by infrastructure and reached by workers and researchers.
The Murchison Radio-astronomy Observatory (MRO) has all that. Which is why it’s home to two of the world’s most important radio telescope projects: the Australian Square Kilometre Array Pathfinder (ASKAP) and the Murchison Widefield Array. Both aim to uncover the secrets of the early universe and its evolution.
Unlike optical telescopes, they detect radio waves emitted by the universe’s cosmic microwave background and interstellar hydrogen gas to stars, black holes and mysterious fast radio bursts. Thanks to the resolution and wide field-of-view they provide, the work they’re doing is unequalled.
But it’s hard to get a sense of the scale and the environment without going there, so I made plans to visit the projects’ directors.
To reach the Murchison Radio-astronomy Observatory, I have to fly 4,000 kilometers (2,500 miles) across Australia from Sydney to Perth, take another flight 250 miles north to the town of Geraldton on the southern coast of Western Australia, then drive another 235 miles inland through the desert scrub. I split the trip into two days.
I’m only an hour into the drive from Geraldton, in the tiny town of Mullewa, when my mobile reception peters out.
Not that having mobile reception would do much good. The MRO is a government-designated Radio Quiet Zone. This means no mobile phones, no refrigerators, no cameras, no computers and no gasoline engines (only diesel, which don’t require a spark gap for fuel ignition). There’s absolutely nothing that can produce radio frequency interference.
This is why it needs to be so far away.
“Radio frequency noise is given off by almost everything,” ASKAP Director Antony Schinckel explains. “Your computers, your car electronics, your refrigerators, machinery in factories. To do radio astronomy these days, you have to get away from these sources of radio frequency interference.”
And that means, he adds, getting away from as much man-made artificial activity as you can.
The MRO’s control center is an unassuming single-story white building. But there’s a lot more to it than meets the eye. To maintain the site’s radio quiet, the entire building is encased in a Faraday cage hidden within the walls, with airlocks that need to be fully secured before one of the two doors can be opened. That metal skin forms a seal that prevents radio waves produced by electronics gear inside the building from getting out.
“The problem is you have to get things in and out,” Schinckel says. “We have to get people in and out, we have to get electricity in and out, we have to get our signals and we have to get air.”
The building’s walls contain sheets of steel welded together at all the joints. Honeycomb grilles provide air ventilation because radio waves can’t traverse tubes with really small diameters. Special shielding protects the electrical wiring. Air locks prevent radio frequency interference from ever escaping the building.
Without that Faraday cage, the site — one of the most pristine radio quiet zones in the world — would be worthless. It’s protecting both ASKAP and the Murchison Widefield Array, a low-frequency radio telescope that operates between 80 and 300 megahertz. These are the same frequencies used for FM radio and TV.
“Those transmissions represent a significant source of interference for us,” says MWA Director Randall Wayth. “The Western Australian Outback represents one of the few places you can go in a stable western country where a radio telescope [will] work in this frequency range.”
The sky’s calling
ASKAP is a midrange frequency radio telescope, operating in the band of 700 megahertz to about 1.8 gigahertz. It consists of 36 dishes (12 of which are currently operational and collecting data). Each is 39 feet across, spread out over a circle roughly 3.7 miles in diameter. The dishes work together as one, an arrangement known as a radio interferometer.
It’s not the biggest radio interferometer in the world. The Atacama Large Millimeter Array in Chile’s northern desert consists of 66 dishes, for instance. But ASKAP has an edge from specially developed phased array feed technology, which opens the telescope’s field of view — allowing it to survey a large part of the sky all at once and deliver results in months instead of years.
The two main telescopes couldn’t look more different. The dishes of ASKAP tower over the desert scrub, white and majestic against the rich red of the earth and the clear blue of the sky. The low-frequency antennas of the MWA are knee-high structures called dipoles, arrayed in 112 squares of four by four, like grids of white aluminum spiders.
Both form radio interferometers. This is an array of multiple radio antennas, the signals of which are combined to achieve greater resolution in a single observation. It’s how the MWA took detailed observations of the entire southern sky in a project called GLEAM. (There’s an awesome Android app that lets you view and zoom in on the visualized radio data).
Its next goal is looking for something called the Epoch of Reionization, a project that will take thousands of hours of observation time.
“At some point in the past, the protons and the electrons in the universe combined to form hydrogen gas, and that process emitted the cosmic microwave background that we see today,” explains Wayth.
Astronomers theorize that galaxies, quasars or the first stars — millions of times brighter than our sun — produced ultraviolet light that was capable of splitting neutral hydrogen atoms back into electrons (negative energy) and protons (positive). That’s ionization.
We know that the vast space between galaxies is filled entirely with ionized hydrogen. Wayth’s team aims to find out when reionization happened, and how. The radio signal they’re looking for can only be found in one place — the low-frequency band where TV and radio also sit.
“The physics of the expanding universe and the frequency of the radio waves emitted by the hydrogen in the early universe forces us to go down to these low radio frequencies,” says Wayth.
Secrets of the universe
ASKAP will probe higher on the frequency band, hoping to answer big questions like how the universe formed and evolved. It will have help from phased array feed technology, which dramatically increases the telescope’s field of view and its resolution. The technology was developed by Australia’s scientific research agency, the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
“Basically we’re trying to use the widefield survey capacity of ASKAP to understand more about both the current structure of the universe and also how it evolved to reach the state that we find it in today,” says Aidan Hotan, ASKAP’s project scientist.
“[It’s] answering the big questions of how everything fits together: How the primordial gas that was formed at the big bang has assembled into things like galaxies and clusters of galaxies.”
ASKAP is particularly sensitive to L band, frequencies of around 1,400 megahertz, where the hydrogen line can be found. Hydrogen is the universe’s fundamental building block, and in its cold, neutral state in the interstellar medium, it emits a radio frequency line at a specific point on the spectrum. That’s the hydrogen line.
By looking at the hydrogen line, ASKAP is expected to survey 70 million galaxies over the entire southern sky, going right to the edge of the visible universe. The project is called Evolutionary Map of the Universe. Another project, the Widefield ASKAP L-band Legacy All-sky Blind surveY (or WALLABY) will examine the hydrogen profiles of roughly 600,000 galaxies to determine their distance, total mass and dark matter content, among other attributes.
It’s not just about galaxies, though. ASKAP has already discovered three of a rare type of signal called a fast radio burst. We don’t know much about FRBs, but that will change as we find more.
“When you only have one object to look at, it’s hard to know what its role is in the bigger picture,” Hotan says. “The more of these things you discover, the more you can tell about the environments in which they formed and existed. You start to really understand how things work.”
The location of Murchison Radio-astronomy Observatory is perfect for radio quiet, but the site definitely posed challenges.
Just building the observatory — 250 miles from the nearest decent-size city — was a test of human ingenuity in a place where temperatures regularly reach nearly 120 degrees Fahrenheit in the summer. And because the area is largely uninhabited (except for a few sparsely scattered homesteads and the nearby Wajarri community), there was practically no infrastructure to support a large research facility.
While exploring the site for interference, the team had to stay on local homesteads, which get their power from the sun and their water from below ground and collected rainfall. But the electrical and data transfer infrastructure — so vital to two major radio telescope projects — was nonexistent.
Australia’s Academic and Research Network (AARNET) — which connects the country’s universities and research centers — handled one leg of the data transfer by installing about 235 miles of fiber optic cable between Murchison and Geraldton. From there, data travels south another 250 miles to Perth along the National Broadband Network, Australia’s new high-speed backbone. It finally ends up at the Pawsey Centre at Curtin University in Perth, home to the most powerful supercomputer in the southern hemisphere.
Things really get complicated when providing power so far to the middle of nowhere. It wasn’t logistically feasible to run electricity cables all that way through to Murchison, so Horizon Power (Western Australia’s electric company) built a power plant especially for the facility that mainly runs on diesel fuel.
But we’re in the Australian desert — very dry and very hot, even in winter. The one resource it isn’t low on is sunlight. That’s why Horizon Power also installed a massive array of 1.6-megawatt solar array to harvest energy from the sun, storing it in a 2.6-megawatt battery system. While the facility can’t run completely without diesel fuel, there are periods it can operate purely on solar power.
The red desert dust around the power plant is silken and fine. It clings to our shoes, gets into everything. It’s a driving hazard, too. I’m here on a still day, but if the wind were up, we’d be blinded.
This, too, proved to be a problem for the electronics inside the MWA antennas: The powdery dust turns highly acidic, with a pH of 4, when it gets moist from the morning dew. It can eat through the protective coating around the electronics. “This is one thing that we didn’t expect,” Wayth tells me.
“We just [used] a better coating.” Problem solved.
ASKAP is a precursor to the Square Kilometre Array project. Split across Australia and South Africa, it’s expected to comprise thousands of dishes and up to a million antennas to become the largest radio telescope ever built.
Both ASKAP and MWA are providing important groundwork for the years ahead. And while there may be some overlap after SKA begins operations in 2020, the telescopes will continue their observations of the universe. ASKAP, with its cutting-edge technology will remain a powerful facility in its own right.
The Murchison Radio-astronomy Observatory is as future proof as it can be.
The frequency bands that the telescopes operate in are relatively well protected, so the growth of electronic personal devices shouldn’t prove to be a problem. But even if it does, no other activities will be allowed in the region if they can’t prove they’re won’t interfere with the radio telescopes.
That’s deeply reassuring. There’s something perfect and pure about the Murchison landscape: The quietness at night, and looking up to see the Milky Way galaxy with the naked eye. The colors of the red dust, the blue sky and the gray-green of the scrub. Seeing the soaring eagles and the footprints of the 5-foot-long goanna lizards in the desert dust. It feels ancient, and it is. And it feels appropriate that this is where we’ll find out more about the early life of the universe.
“My people have lived here for 30,000 years,” says Leonie Boddington, a member of the local Wajarri community and Aboriginal Liaison Officer with Australia’s scientific research agency, the CSIRO. “I’m hoping they can tell me more about where we’ve all come from.”
Road Trip 2016: Reporters’ dispatches from the field on tech’s role in the global refugee crisis.
Road Trip 2015: CNET hunts for innovation outside the Silicon Valley bubble.