His conflict with the Catholic Church arose because deep in his heart Galileo was a believer. There was for him no path of compromise, no way to have separate secular and theological cosmologies. If the Copernican system was true as he believed, what else could Galileo do but fight with every weapon he had in his arsenal of logic, rhetoric, scientific observation, mathematical theory, and cunning insight, to make his Church accept a new system of the universe?
However we select from nature a complex [of phenomena] using the criterion of simplicity, in no case will its theoretical treatment turn out to be forever appropriate (sufficient)…. I do not doubt that the day will come when [general relativity], too, will have to yield to another one, for reasons which at present we do not yet surmise. I believe that this process of deepening theory has no limits.
Human exploration and colonization of Mars will keep us busy for hundreds, even thousands, of years. During that time, there will be advances in nanotechnology, space sailing, robotics, biomolecular engineering, and artificial intelligence. These advances are occurring even now, affecting our outlook about what it means to be human and engage in human activity. Those technologies will not merely allow us to stay home on Earth and Mars, but our minds will extend our presence throughout the universe so that we will not need or want to extend our bodies there even if we could, which I think is doubtful.