Is it false that the names of the seven days of the week are derived from the names of the members of the solar system that are visible to the naked eye?

It is false.

The names of the days of the week recall:

-- the Sun

(but Spanish: "Domingo")

-- the Moon

-- Tiw, the Germanic God of War

(although in German: "Dienstag")

-- Wodin, Wotan, Odin, chief deity of the Germanic peoples

(although in German ... "Mitwoch", meaning "mid-week")

-- Thor, old English Unresdæg, literally "day of thunder"

(German: "Donnerstag" ... "Thunderday")

-- Old English "Frigedæg", day of the goddess "Frigg", from a prehistoric

Germanic verb "to love", also the ancestor of the English "friend" and "free".

-- Saturn's day

(Spanish: "Sabado", meaning "Sabbath")