Arecibo Observatory

Arecibo Observatory in Barrio Esperanza, Puerto Rico, emerged from Cold War research and became one of the world's leading centers for radio astronomy, planetary radar, and ionospheric study. Opened in 1963 and later operated under the National Science Foundation, it was defined for decades by its 305-meter telescope, built into a natural sinkhole and long the largest single-aperture telescope on Earth. Its work ranged from studying the upper atmosphere and Solar System bodies to SETI and tracking near-Earth objects. After years of funding strain and storm damage, cable failures in 2020 destroyed the telescope. The site continues with other facilities and a renewed focus on research, education, and public outreach.

Puerto Rico · United States