The Symphony of the Skies

Just as different instruments are needed to play a symphony, different radio telescopes are required to explore the universe across its vast spectrum of wavelengths. Each wavelength reveals a unique part of the cosmic story, from the whisper of cold molecular clouds to the roar of supermassive black holes.

In the early 1970s, this symphony expanded with the arrival of powerful instruments like the Effelsberg 100m telescope, tuning into the cosmos between 2 and 75 cm, and the Westerbork Synthesis Radio Telescope (WSRT), which focused on 6, 21, and 50 cm wavelengths. Meanwhile, a new “window” to the universe opened in the millimeter range, when astronomers detected carbon monoxide (CO) in the Galaxy at 2.6 mm using the NRAO 36 ft mm-telescope in 1970—a discovery that revolutionized our understanding of interstellar chemistry.

Between 1972 and 1978, an international wave of innovation followed, with Brazil, Finland, Sweden, Spain, Korea, and the Five College Radio Astronomical Observatory (FCRAO) acquiring advanced radome-enclosed antennas, capable of observing at 3 mm - and, in the case of FCRAO, even 1.3 mm. The Helsinki General Assembly in 1978 became a milestone moment, where the scientific community converged to discuss the frontiers of millimeter astronomy, low-noise receivers, and ambitious plans for telescopes spanning 10 to 45 meters, positioned in the highest, driest locations on Earth.

Yet the vision of radio astronomy did not stop at Earth's surface. With the advent of Very Long Baseline Interferometry (VLBI), telescopes were linked across continents, achieving resolutions once thought impossible. And even then, the dream grew larger - extending beyond our planet, as scientists laid the groundwork for radio observatories in space.

Throughout these breakthroughs, one force remained constant: URSI. The organization has not only witnessed but actively facilitated access to these groundbreaking instruments, ensuring that radio science remains a frontier of discovery

From the longest wavelengths to the shortest, from the ground to the stars, URSI continues to unite the world’s brightest minds in a mission to decode the universe - one frequency at a time