ALMA is the biggest array of telescopes in the world and the largest astronomical project ever attempted, a truly global partnership between scientists from Japan, Europe, Canada, the US and Chile. It is located deep in the Atacama desert of Chile, in an inhospitable region called Chajnantor Plateau. Because of its altitude, dry air (this is the driest place on Earth), nearly non-existent cloud cover (320 clear skies per year), and lack of both light pollution and radio interference, it is probably the best location in the world to conduct astronomical observations. It is largely transparent to the millimeter and submillimeter wavelength range that ALMA is designed to detect. Most of the photons in the Universe are in this wavelength, that lies between what is traditionally considered microwaves and infrared waves. Star formation occurs in dense molecular clouds observable only in the submillimeter range, and most of this radiation is absorbed by atmospheric water vapor. This is why such a dry location is so important.
The rarified atmosphere at this altitude is very demanding for humans, this is why the telescopes are assembled from parts arriving from different parts of the world at a camp at 3000m and then transported to their final position. The final configuration should consist of around 60 antennas. ALMA is by no means alone in the Atacama desert. The European Southern Observatory operates two major observatories in the Atacama: the La Silla Observatory and the Paranal Observatory, which includes the Very Large Telescope. Another impressive piece of equipment, the CCAT, Cornell Caltech Atacama Telescope, currently under construction by an international consortium, will also be located in the area, near the summit of Cerro Chajnantor, about 600 m above and only 5 km from ALMA.
ALMA will give astronomers an unprecedented window on the cosmos, enabling groundbreaking studies into areas such as the physics of the cold Universe, the first stars and galaxies, and even directly imaging the formation of planets. This video shows the ALMA facilities. This second HD time-lapse video was shot around ALMA to celebrate its first observations. It’s 5 marvelous minutes of an strange pleasure…the realization that we live in a rock that spins at 1000km per hour, a tiny speck of dust inside a cloud that travels at 250km per second across the inmensity of the Universe.