Arecibo Observatory is a distinctive, massive 305-metre (1000-foot) radio telescope located in Puerto Rico, and the largest single-dish telescope ever built. Since construction was completed in 1963, the observatory has been used to make important discoveries in radio astronomy as well as gathering radio data for processing as part of the Search for Extraterrestrial Intelligence (SETI). The distinctive dish has been used in several television shows and movies, including Contact and Goldeneye (where it is portrayed as a secret Cuban military installation). Cornell University operates Arecibo Observatory under the formal name, National Astronomy and Ionosphere Center (NAIC).
– Design and Construction –
Arecibo Observatory had its genesis in the work of Cornell ionosphere researcher William Gordon, who, with military assistance from the Advanced Research Projects Agency (now DARPA), constructed the dish in an enormous karst sinkhole seemingly tailor-made for the purpose in Arecibo, Puerto Rico.
Construction of the dish lasted three years. The resulting masterpiece was 305 metres across, constructed out of tens of thousands of aluminum panels. Suspended 500 feet above the dish itself is the massive receiver, on a platform which itself weighs hundreds of tons. By adjusting the receiver platform, the observatory can effectively cover a range of sky in a 40-degree cone, which includes – at the appropriate points and their and Earth’s orbit – all of the other seven planets in the solar system.
– Research and Discoveries –
Since it went online in the 1960s, Arecibo Observatory has made vital contributions in several areas of astronomy. Some of its first discoveries included new measurements of the rotation rate of the planet Mercury, the discovery of a neutron star and supernova remnant now known as the Crab Pulsar, as well as several subsequent pulsar discoveries, including the recent discovery of the fastest-spinning one ever identified, PSR J1748-2446ad, which is located 18,000 light-years away and rotates at the stunning speed of 642 times per second. In the intervening decades, Arecibo Observatory’s radio detection capabilities have been used to identify extrasolar planets, study and map planets in our own solar system, identify the molecular composition of distant galaxies, and even locate asteroids.
In addition, one of Arecibo Observatory’s important missions has been to collect data for the Search for Extraterrestrial Intelligence (SETI), as well as to beam messages into space in the hopes that they will one day be detected and decoded by alien civilizations (a practice which physicist Stephen Hawking objects to). In 1974, the so-called Arecibo Message was transmitted toward M13, a globular cluster roughly 25,000 light-years from Earth. The highly successful SETI@home project, which sends raw data to a large network of home and business PCs for processing, draws its data from the Arecibo Observatory.
As of 2010, research at Arecibo Observatory does continue, subject to approval by a board which reviews research proposal and grants usage time for the telescope.
– The Future –
Currently, the Arecibo Observatory is operated by Cornell University, under a funding agreement with the National Science Foundation. However, the Foundation has for several years recommended cutting funding and, ultimately, closing down the telescope entirely. NASA, which also used to contribute to the observatory’s budget, has already withdrawn. Although private or foundation funding is always possible, and Cornell continues to operate the facility for the time being, the withdrawal of National Science Foundation funding would almost certainly mean the observatory would be closed permanently.
The loss of Arecibo Observatory would mean the end of one of the most distinctive and recognizable symbols in astronomy. At the same time, many functions of the massive dish have already been superceded by large arrays of smaller dishes here on Earth, as well as by orbiting telescope satellites. Russia’s RATAN 600 is already technically the largest radio telescope, with a circle of reflectors stretching 576 metres across (although it is not a single massive dish, like Arecibo). Currently, China is constructing a 500-metre single-aperture dish which will supercede Arecibo, called FAST, which also makes use of a natural depression.
