At 5000 metres above sea level, high upon the Chajnantor Plateau in Chile, the antennas of the ALMA Observatory peer skywards, scanning the Universe for clues to our cosmic origins. This plateau is one of the highest observatory sites on Earth.
Visible amongst the thousands of stars on the right side of this image are the Small and Large Magellanic Clouds, appearing as luminous smudges in the sky. These cloud-like objects are both galaxies — two of the closest galactic neighbours to our galaxy, the Milky Way.
ALMA's main aim is to observe the coldest and most ancient objects in the cosmos — known as the "cold Universe". The array measures radiation emitted in the millimetre and submillimetre wavelengths, which lie in between infrared and radio waves in the electromagnetic spectrum. It features 66 mobile antennas which can be moved and configured over the ALMA site to meet the scientists' requirements, making it the biggest astronomical experiment in existence.
This amazing picture of the ALMA landscape was taken by ESO Photo Ambassador Stéphane Guisard, an optics engineer at the European Southern Observatory's Very Large Telescope in the Atacama Desert, Chile.
Explanation from: http://www.eso.org/public/images/potw1431a/