Some people just think big.
The radio telescope at Arecibo Observatory is the largest in the world. Its dish is 1,000 feet from rim to rim and covers the equivalent of about 18 acres, or 26 football fields. If the Washington Monument were set on the dish's aluminum surface, its point would just about reach to the top of the support structure for the dome of the Gregorian telescope, perched with other instrumentation 450 feet above the reflector, and about 1,300 feet above the ground. It is the planet's most sensitive ear to the sky. As director of the SETI Institute's Project Phoenix, Jill Cornell Tarter, a 1965 Cornell alumna, scans the skies using the Arecibo radio telescope and two smaller ones in the continental United States looking for signals that indicate life exists on other planets.