Orion the hunter watches over ALMA

With all 66 of their backs turned to the constellation of Orion, the antennas of the Atacama Large Millimeter/submillimeter Array (ALMA) sit high on their perch on the Chajnantor Plateau in the Chilean Andes.

Illustrating nicely why this spot was chosen for the array is an impressively clear view of the Orion Nebula — otherwise known as Messier 42. It lies in the centre of the image, with the dazzling red of the star Betelgeuse, otherwise known as Alpha Orionis, off to the right. These are two of the most impressive sights in the night sky.

Betelgeuse is a red supergiant and notable for being a likely candidate amongst the stars in our galaxy to become a supernova in the near future. Near future on a cosmic scale  — a recent report suggests in around 100 000 years, which is a mere galactic blink. When this does happen, it will become the brightest object after the Moon in our night sky.

ALMA itself, however, is looking deeper into the cosmos to study the oldest and coldest of places by detecting light at millimetre and submillimetre wavelengths. Its antennas can be moved about the site independently and they search the skies in perfect synchrony, using a process known as interferometry to achieve results that would otherwise require a single telescope of about 14 000 metres in diameter.