Giordano Bruno, born Filippo Bruno, was a Dominican friar, philosopher, mathematician, and astrologer who lived in Italy during the 16th century. He proposed several important theories about the universe, including that it was infinite, with no center, and that stars were actually suns with their own solar systems which could possibly harbor alien life. He was executed by the Catholic church in 1600 for heresy after openly denying several Catholic doctrines.