High altitude super-scope

Perched on top of one of Mexico's highest mountains is a gigantic, half-built telescope that scientists hope will reveal more secrets of the universe's early years than any before it.

With a base like a launching pad and an antenna the size of a big Ferris wheel, the telescope will be able to pick up electromagnetic radiation known as millimetre waves emitted 13 billion years ago, when the first stars burst into existence, astrophysicists say.

'With this we are going deeper into space and further back in time,' said astrophysicist Itziar Aretxaga, yelling over the noise of workers banging and welding.

The Large Millimeter Telescope or LMT, is a US-Mexican project being built on the 4,580-metre summit of Sierra Negra, Mexico's fifth-highest peak. Scientists hope to detect clouds of cold cosmic dust waves emitted by the first stars as they were formed after

the big bang that created the universe 13.7 billion years ago. At the same time, they are likely to spot thousands of new galaxies.

But the telescope being located so close to the heavens comes at a price. Sierra Negra, an extinct volcano to the east of the city of Puebla, central Mexico, was chosen for the site of the LMT because of its height and mild climate. Millimetre telescopes work best at altitudes where the percentage of water vapour in the air is low.

Its 19-degree latitude position also gives a perfect view of the southern sky and the centre of the Milky Way.