On December 1, 2020, the iconic Arecibo Radio Telescope in Puerto Rico collapsed

Remembering the Arecibo Radio Telescope: Four Years Since Its Collapse**

On December 1, 2020, the iconic Arecibo Radio Telescope in Puerto Rico tragically collapsed due to the failure of its aging support structure. This event marked the end of an era for one of the most significant instruments in radio astronomy.

**About the Arecibo Observatory:**
- **Location**: Near the city of Arecibo, Puerto Rico, at an altitude of 497 meters above sea level.
- **Commissioned**: November 1, 1963.
- **Reflector Size**:
- Diameter: 304.8 meters.
- Depth: 50.9 meters.
- Surface Area: Approximately 73,000 m².

The telescope's massive reflector was nestled in a natural karst sinkhole and comprised 38,778 perforated aluminum plates, each about 1 x 2 meters, supported by a grid of steel cables. Its antenna feed, suspended on 18 cables from three towers, could move to aim the telescope at specific points in the sky.

**The Collapse:**
In August 2020, one of the cables supporting the telescope snapped during an Atlantic typhoon. Another cable failed in November, causing significant damage, including a 30-meter crack in the reflector. Subsequent tests revealed that the structure was too unstable for safe repair, prompting the decision to decommission the telescope.

On December 1, 2020, the remaining cables gave way, and the entire structure collapsed.

**Impact on Astronomy:**
The Arecibo Telescope, one of the largest single-aperture radio telescopes ever built, was a vital tool for studying the universe. Its sensitivity made it unparalleled in detecting faint signals, and it played a key role in the search for extraterrestrial civilizations. With its loss, the Green Bank Telescope in West Virginia became the most powerful U.S. radio telescope, though it is five times less sensitive than Arecibo.

The collapse of Arecibo was a monumental loss to the scientific community, leaving behind a legacy of groundbreaking discoveries and an enduring impact on astronomy.