>>358Arecibo was unique in that it was capable of both transmitting and receiving radio waves. Most other radio telescopes are only capable of receiving radio waves. The only other telescopes capable of transmitting are much smaller and are lower power. The reason why that's significant is because it meant that Arecibo was capable of radar, which allowed it to accurately determine the distance between the Earth and the various celestial bodies within the solar system, which allowed us to accurately track the paths of asteroids and such.