Built in 1963, the Observatorio de Arecibo is a curved dish telescope set into the earth on what was once a coffee plantation in the upper regions of Puerto Rico’s karst country. The landscape is distinguished by an underground system of limestone caves that has transformed the topography into clusters of fertile green hills and sinkholes. It is because of the landscape’s natural depressions, which were big enough to contain the telescope’s dish, that the observatory was built here.

Arecibo Observatory. Photo © Frank Van Den Eijnden/123rf.

Arecibo Observatory. Photo © Frank Van Den Eijnden/123rf.

To convey a sense of its immensity, consider these statistics: The aluminum-lined dish is 1,000 feet wide from rim to rim and encompasses 18 acres. The receiver is on a 900-ton platform suspended 450 feet above the dish on a 304-foot moveable arm. Cornell University managed the observatory for four decades until 2011, when the National Science Foundation won a five-year bid to manage it. The observatory employs about 140 scientists and engineers from around the world.

Many significant astronomical discoveries have been made at the observatory in the last four decades. Joseph Taylor won the Nobel Prize in 1993 for discovering the first binary pulsar from Arecibo. Other discoveries made at Arecibo include the discovery of polar caps on Mercury and the existence of planets around a pulsar.

But Arecibo’s most infamous contribution to science has been as the center of operations for the Search for Extraterrestrial Intelligence Institute’s Phoenix Project, which monitored the telescope for signs of intelligent life in the universe. A respected organization made up of some of the world’s foremost scientists, including three Nobel Prize winners, the SETI Institute and its Arecibo research project were funded through grants by NASA for many years before the organization became private in 1993. The project is not as “ET” as it sounds, though. The telescope doesn’t so much “seek” intelligent life as listen for radio signals that might indicate its presence. Nevertheless, its otherworldly visage has made it a popular backdrop for filmmakers, including the Jodie Foster movie Contact.

There’s one more thing about the Arecibo Observatory that is unique, and that is its longevity. Most major telescopes become obsolete after about 10 years as technological advancements are made, but not Arecibo. Multimillion-dollar upgrades have been made through the years that have extended its viability. Most recently a new “eye” was installed in 2004 that enables it to take photographs of space.


Excerpted from the Fourth Edition of Moon Puerto Rico.