> so what do they target? Traditionally, Moon, Venus, asteroids. Also: https://en.wikiversity.org/wiki/Radiation_astronomy/Radars#Arecibo_Observatory https:/

> so what do they target? Traditionally, Moon, Venus, asteroids. Also: https://en.wikiversity.org/wiki/Radiation_astronomy/Radars#Arecibo_Observatory https://en.wikiversity.org/wiki/Radiation_astronomy/Radars#A... "the round trip light time to objects beyond Saturn is longer than the time the telescope can track it, preventing radar observations of more distant objects." Also: https://en.wikipedia.org/wiki/Arecibo_message https://en.wikipedia.org/wiki/Arecibo_message "The Arecibo message is a 1974 interstellar radio message carrying basic information about humanity and Earth sent to globular star cluster M13. It was meant as a demonstration of human technological achievement, rather than a real attempt to enter into a conversation with extraterrestrials." "The message consisted of 1,679 binary digits, approximately 210 bytes, transmitted at a frequency of 2,380 MHz and modulated by shifting the frequency by 10 Hz, with a power of 450 kW. The "ones" and "zeros" were transmitted by frequency shifting at the rate of 10 bits per second. The total broadcast was less than three minutes."