Galileo read his own Bible, didn't listen to the established church leaders, 'cause God said this:
Here are a couple of my favorite quotes from Galileo.
"It is surely harmful to souls to make it a heresy to believe what is proved."
"I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use."
Guess Columbus was not afraidof dropping of the earth cause he read his Bible.
Can't speak for Columbus but here is why Magellan wasn't afraid of sailing off the edge.
Ferdinand Magellan -
“The Church says that the Earth is flat, but I know that it is round. For I have seen the shadow on the moon and I have more faith in the Shadow than in the Church.”