The idea received a boost in 1991, when the Arecibo radio telescope in Puerto Rico detected unusually radar-bright patches at Mercury‘s poles, spots that reflected radio waves in the way one would expect if there were water ice.
The idea received a boost in 1991, when the Arecibo radio telescope in Puerto Rico detected unusually radar-bright patches at Mercury‘s poles, spots that reflected radio waves in the way one would expect if there were water ice.