Giordano Bruno was such an outsized, rebellious shooting star of a human being that it's hard to believe he was actually a mortal. He was a contemporary of Galileo's, but his theories were much more controversial (if you can believe that!). Not only did Bruno believe that the Earth revolved around the Sun, he thought the Sun was just one star of billions, and passionately argued that alien civilizations were strewn across the universe. Belief in a "plurality of worlds" was deemed blasphemous by the Catholic Church, and they gave Bruno a stern warning to shut up or face the consequences. This is where Bruno proves to be beyond badass—he told the Inquisition to do its worst.
They did. For 7 years, Bruno was imprisoned and questioned, but he refused to recant his belief that the stars were distant suns supporting all kinds of life. The Church proclaimed him to be a heretic and sentenced him to death. He calmly told his judge, "perhaps you pronounce this sentence against me with greater fear than I receive it." WHAT?! Talk about balls. But he was completely right that the Church feared him, so much so that he was gagged at his execution to prevent him spreading his ideas to the crowd. The least we can do is heed this science martyr's timeless advice, that "truth does not change because it is, or is not, believed by a majority of the people."