World's largest radio telescope just got a heart transplant

The Atacama Large Millimeter/submillimeter Array (ALMA), the largest radio telescope in the world, has undergone what can only be described as a 'heart transplant'. A hydrogen maser was successfully installed into the array, marking an essential advancement in the quest for astronomical breakthroughs.

The new hydrogen maser, an advanced atomic clock, uses the properties of the hydrogen atom to provide an extremely precise and stable frequency reference, which is crucial for Very Long Baseline Interferometry (VLBI) observations, enabling synchronization of cosmic signals received by networks of telescopes spread across the globe.

The upgrade was funded by the National Radio Astronomy Observatory (NRAO) and the seamless integration was supported by the Massachusetts Institute of Technology Haystack Observatory.

The original maser will continue to function as a backup system to ensure the utmost reliability and continuity in observations. The new maser, operational since January 2024, ensures a high level of accuracy essential for explorations of the Universe, especially in the longest baselines where precision is paramount.

ALMA is composed of 66 high-precision antennas, which operate on wavelengths of 0.32 to 3.6 mm. Its main array has fifty antennas, each with 12-meter diameters, which act together as a single telescope - an interferometer. With this upgrade, the observatory is set to embark on a new era of discoveries.