World’s Largest Space Observatory Opened in Chile

    Sugar molecules in the gas surrounding a young Sun-like star (Credit: ESO/L. Calçada & NASA/JPL-Caltech/WISE Team)

    Inaugurated on 13th March, the Atacama Large Millimetre Array (ALMA) radio telescope located in the Andes in Northern Chile has taken a decade to build, costing $1.4 billion. The array consists of 66 antennas lined up to gaze towards the heavens in unison, the equivalent of a 10 mile wide telescope. ALMA, meaning “soul” in Spanish, will be fully operational by October.

    What is it used for?

    ALMA will be primarily used for studying the formation of the first stars and galaxies billions of years ago. It will observe the formation process of developing planets and still-forming stars. In addition, ALMA will allow scientists to learn in detail about the complex chemistry of the giant clouds of gas and dust that spawn stars and planetary systems.

    Other specialties include mapping gas and dust in the Milky Way and other galaxies, analyzing gas from an erupting volcano on Jupiter’s moon, Io and studying origin of the solar wind. 

    How does ALMA work?

    “A signal from the sky captured by two or more antennas are combined, analyzed, and thus information about its source (whether a star, a planet, or a galaxy) is obtained. By combining the radio waves collected by several antennas, it is possible to construct images. Such images are comparable to those that would be obtained with an hypothetical giant telescope or antenna, 14,000 meters in diameter. Since constructing and operating an antenna that size is technically impossible (at least with current technologies), constructing several small antennas and using them combining their output is far more feasible.”

    “To operate properly, ALMA must have its 66 antennas and electronics working in perfect synchrony, with a precision of one millionth of a millionth of a second.” (


    At an altitude of 5,100 meters (16,400 feet) above sea level, the Chajnantor plateau is uninhabitable. Engineers carrying oxygen cylinders visit the observatory from base stations. Chile is the one of the most suitable places for hosting ground-based observatories on Earth. This plateau was selected for its dryness, altitude and flat land. If there were water droplets in the atmosphere, it could distort radio signals coming to the telescope and degrade quality of the observations. Beside, the southern sky has many unique objects like the center of the galaxy, large and small Magellanic Clouds. The other-worldly atmosphere over here has been used to shoot Mars scenes in movies.

    An international collaborative effort of institutions in Europe, North America and East Asia and Chile. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA. Observation time will be divided and allocated to the parties invested in the project.