On Mon, 7 Dec 2020 09:36:54 -0800, a425couple
wrote:

from
https://www.sciencenews.org/article/...my-discoveries

(At the citation are pictures and graphics.)

How did a radio telescope detect ice on Mercury?

Oh, sorry. In reading further, under the part about mapping the
Venusian surface, it says that Arecibo used radar. I was totally
unaware that Arecibo was a transmitter facility as well as a receiver.
I had no idea.

--
//Steve//