When I was little, I used to think that planets were named after their features: for example, Jupiter was named after the king of gods because of its size; Saturn was named after the god of crops and calendar because of his color and his rings resembling a clock; Uranus and Neptune after the gods of the sky and sea because of their respective colors, etc.

But then I learned that at the time of their discovery people had no way to know about most of those features. I know that there is a kind of logic behind some of them (Venus because of its brightness, Mars because of its red color resembling blood), but ancient people didn't know about Jupiter's size, nor did the discoverers of the ice giants know about their color (that I know of).

So my question is, to what extent is it purely a coincidence that these names seem to describe them so well? Is there a reason behind the similarities, or was it just luck?