Puerto Rico is Listening Puerto Rico Coast. |The SETI team
searches for radio frequencies, using large telescopes such as
the Arecibo Observatory, Credit: David Parker / Science Photo
Library At first glance, Puerto Rico seems a strange place to
eye the sky. A tilted block of land guarding the eastern end of
the Greater Antilles, this island boasts no soaring mountains on
which an optical telescope could perch, nor an unpopulated
outback that would suit the signal-sensitive ears of a radio
array. What Puerto Rico does have is geology and location.
Stretching across the islands northern edge from the suburbs of
San Juan to the western town of Aguadilla is a bumpy, limestone
terrain known as karst. Pockmarked from thousands of millennia
of rain, the karst is a jumble of haystack hills and broad
sinkholes. One of the latter, about 8 miles south of the coastal
city of Arecibo, is a perfect natural dimple to house the worlds
biggest single-dish antenna: the Arecibo radio telescope.
Cornell University, which built