Not sure. But to map polar ice in mercury it was necessary to use the Arecibo radio telescope as radar[1], with the benefit we knew previously where to point th

Not sure. But to map polar ice in mercury it was necessary to use the Arecibo radio telescope as radar[1], with the benefit we knew previously where to point the instrument, exactly. Given planet nine is hundreds of times more distant, it would probably take a humungous radio telescope and a lot of power to conduct the search. [1] https://www.nature.com/articles/369213a0 https://www.nature.com/articles/369213a0