World's largest ground-based space array to open in Chile

In a super-arid desert at an altitude of five kilometres, with almost no humidity or vegetation, the world's largest ground-based astronomy project is opening for business, ready to probe the universe with unprecedented might.

"What is so very special about this place is that, right here above our heads, there is virtually no water vapour. There is just so little that whatever light is emitted from a heavenly body, galaxy or star, it gets here with no interference," said Gianni Marconi, an astronomer with the Atacama Large Millimeter-submillimeter Array, better known as ALMA (Spanish for "soul").

"And this is the largest observatory that has ever been built."

ALMA is a joint effort among North American, European and Asian agencies.

And when scientists went looking for a place to put this world's biggest ground array of telescopes, they looked for a spot that was high in altitude, low in humidity, sunny and boasting fairly easy logistical access.