NSF News

A decade of unveiling the hidden universe: ALMA at 10

On March 13, 2023, astronomers around the world mark the 10th anniversary of the Atacama Large Millimeter/submillimeter Array, or ALMA, the world's largest radio telescope. Over the past decade, the international ALMA collaboration — led by the U.S. National Science Foundation's National Radio Astronomy Observatory, or NRAO, the European Southern Observatory and the National Astronomical Observatory of Japan — has revolutionized our understanding of the universe and has unveiled its secrets, from the formation of planets, stars and galaxies to deciphering the chemistry of the cosmos, even taking part in capturing the first images of black holes. 

ALMA's decade of success started with early science observations in 2011, nearly a full two years before the telescope was inaugurated. This test period for ALMA yielded complex and beautiful images, revealing star formation and violent galaxy mergers in the Antennae galaxies at a level of detail no other telescope on Earth had ever attained. 

“ALMA has captured the world’s imagination since it unveiled its first images more than a decade ago, and it has opened new windows on the Universe that could not have been opened otherwise," said Karen Marrongelle, U.S. National Science Foundation Chief Operating Officer. "Our commitment to ALMA now and for the future is the same as it was then: to develop the technology that unlocks and expands our knowledge of the Milky Way and every other galaxy in our Universe.”

ALMA consists of 66 antennas spread over nearly 10 miles (16 kilometers) on the Chajnantor Plateau of the Chilean Andes at 16,404 feet (5,000 meters) above sea level. The technology that makes the telescope special is borne of an international collaboration of 21 countries from across North America, Europe and East Asia. NRAO's Central Development Laboratory is responsible for the development of the Band 6 receiver, widely recognized as the most sensitive radio astronomy receiver in the world. ALMA was approved earlier this year for the development of a new central correlator and digital transmission system, upgrades that will eventually increase the telescope's data production capacity by a factor of 200-400 times. This technology and other innovations like it have supported scientists using ALMA in producing more than 3,000 scientific publications to date. That's nearly one publication per day for a decade.

Among ALMA's most notable contributions are the clearest pictures of planet formation observed around the young star HL Tau by NRAO scientists in 2014 and the supermassive black holes M87* and Sgr A*, observed by the Event Horizon Telescope Collaboration in 2019 and 2022, respectively.