Sir Arthur Eddington was a top British astronomer best known for venturing out on a boat off Africa in 1919 to observe the bending of starlight around the sun during a total eclipse. The theory of general relativity of Albert Einstein predicts twice the bending of light around massive objects compared to Newton's theory, and an eclipse is required to darken the sun so that the starlight may be seen in proximity to the sun.
Eddington liked publicity and probably dreamed of winning a Nobel Prize, and upon his return to England declared that his observations proven the theory of relativity. That was good enough for reporters and historians, but the Nobel committee was not impressed and declined to give him an award. Recent analysis of Eddington’s work revealed that he was biased in selecting his data, and that overall his data was inconclusive about the theory of relativity.
Eddington next promoted the theory of relativity to the English-speaking world in his Mathematical Theory of Relativity (1923). As the title suggests, this theory was more a mathematical vision of how the universe should be, rather than what it actually was. When a reporter asked Eddington whether only three people even understood the theory, Eddington supposedly retorted, "Who's the third?"
But Eddington did not fare well after that. He strongly opposed a theory about massive stars known as white dwarves put forth by Indian physicist Subrahmanyan Chandrasekhar, but Eddington was proven wrong and Chandrasekhar later won a Nobel Prize for his work. Eddington finally lost all credibility when he first insisted that a physical constant (the fine structure constant) measured to be close to 1/136 must precisely equal 1/136 to make the math easier, but when later measurements suggested a value closer to 1/137 Eddington insisted that it must precisely equal to 1/137 instead. He was wrong both times.