ALMA casts a cold eye on the sky

One of the grandest ground-based astronomy projects of the coming decade is taking shape in the arid desert of northern Chile. These antennas, each measuring 12 metres across, are part of a much larger array that will eventually be spread a distance of around 16 kilometres.

The Atacama Large Millimeter/submillimeter Array, or ALMA, is being constructed at an altitude of 5000 metres on the Atacama desert's Chajnantor plateau, one of the driest places on the planet. This lack of moisture, combined with the thin atmosphere at high altitude, offers ideal conditions for observing the cosmos at the still mysterious millimetre and submillimetre wavelengths which are emitted by cooler objects.
The first 16 antennas should be in place this month, and scientific observations are scheduled to begin at the end of September. When it is completed in 2013, ALMA will have fifty 12-metre antennas in its main array, plus an additional array of twelve 7-metre and four 12-metre antennas. This will allow it to produce images of extended objects in the night sky such as giant cosmic clouds of gas and dust. All the dishes will work together to observe the sky as one.

"Even using just the first 16 of its 66 antennas, ALMA will already surpass the capabilities of all existing telescopes of its kind, and will provide new insights into star formation as well as the origins of galaxies and planets," says Paola Andreani, manager of the European ALMA Regional Centre at the European Southern Observatory.
ALMA will be used to probe the first stars and galaxies that emerged from the cosmic "dark ages" around 13 billion years ago. The array will also study molecular clouds, the dense regions of gas and dust where stars are born.
The ALMA project is a partnership of Europe, North America and east Asia in cooperation with Chile.
Click here to see a timelapse video of ALMA scanning the night sky.

Source New Scientist