Eyes on the sky at the Atacama Large Millimeter/submillimeter Array.

STPHANE GUISARD/ESO

The car toils upwards along the sinuous road, its engine tuned for the thin air. The clumps of cactus and grass along the road soon give way to bone-dry lifelessness. By the time the car reaches 4,000 metres above sea level, Pierre Cox has a bit of a headache. By the time it reaches the 5,000-metre-high Chajnantor plateau one of the highest, driest places on Earth, and one of the best for astronomy the altitude is affecting his bladder. Cox, the incoming director of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, is about to glimpse the giant telescope dishes he will soon be responsible for. But first he must find a toilet.

Cox slides out of the car and staggers into ALMA's glass and steel operations centre. The current director, Thijs de Graauw, a trim 71-year-old Dutchman, follows Cox inside and sits down. For him, journeys like this occur weekly if not daily but he knows that they are no joke. First-timers get a mandatory medical screening before being allowed up to the plateau, and regular shift workers pad around the building with tubes in their noses and oxygen tanks on their backs. Everyone okay? De Graauw asks the group of astronomers who have accompanied Cox to ALMA on this December day. No victims yet?

Cox re-emerges from the toilet, puts on wraparound sunglasses and, slightly dizzy, heads outside with the group. Scattered across the surrounding plain of brown volcanic soil are dozens of huge white radio antennas, looking as out of place as the stone statues on Easter Island. High on this cold and lonely plateau, they are gathering photons from the cold and lonely parts of the Universe the dimly glowing clouds of dust and gas where stars are born. Their signals are then combined into images that have a resolution better than that of the Hubble Space Telescope.

The stillness of the tableau breaks as the dishes begin to tilt and swivel in unison. My goodness, says Cox, hushed by the sight of so much metal moving so quickly and quietly.

But the choreography is not quite uniform. Clustered tightly in the middle of the array are 12 dishes, each 7 metres across, and four 12-metre dishes, from Japan. Spaced farther out are 25 dishes, each 12 metres across and fitted together like pie slices, from the United States. And scattered among those are the first of 25 dishes from Europe, each 12 metres across top-of-the-line carbon-fibre devices pivoting on silky-smooth gearing.

The last of those European antennas will not be installed until the end of 2013, when ALMA will finally reach its full complement of 66 dishes. Rather than wait until then, however, the project held a formal inauguration ceremony on 13 March to celebrate the collaboration that made it all possible. A total of 19 countries have contributed to ALMA, through three primary partners: the European Southern Observatory (ESO); the National Astronomical Observatory of Japan; and the US National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, funded by the US National Science Foundation (NSF).

Geoff Brumfiel talks to Eric Hand about his 5,000-metre ascent to ALMA.

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Radio astronomy : The patchwork array