Shaping Modern Science explores some of the greatest scientific discoveries of our time and the people and events behind them. Fascinating stories reveal the difficulties scientists faced as they challenged existing beliefs and worked to advance scientific understanding. In 1912, German meteorologist Alfred Wegener published his groundbreaking theory of continental displacement. His theory proposed that the continents were once a single land mass but had slowly moved apart over millions of years. What Is the Theory of Plate Tectonics? describes how Wegener's theory challenged prevailing views of the time. Years after his death, his theory was embraced by scientists and became the basis for modern earth science.