Science in the 20th Century: A Social Intellectual Survey (Repost)

As the 19th century drew to a close, the age-old quest to understand the physical world appeared to be complete except for a few minor details. "It seems probable that most of the grand underlying principles have been firmly established," said Albert Michelson, the first American scientist to win a Nobel Prize.

But when Michelson made that prediction, he never dreamed that one of the "details"—his own curious discovery that the speed of light is constant no matter how fast an observer is moving—would soon be explained by a revolutionary theory that redefined the very concepts of space, time, matter, and energy.

The author of that theory, called relativity, was Albert Einstein. He would also lay the foundation for a strange new picture of the atom, which would eventually lead to quantum mechanics and a succession of startling discoveries driving physicists to ever more bizarre theories of the ultimate nature of the universe.
Imagine Today's Science from a Turn-of-the Century Perspective

Scientists in 1900 had no inkling of the other mind-boggling developments that lay in wait: plate tectonics, genetic engineering, space probes, nanotechnology, Big Bang theory, electronic computers, nuclear weapons, artificial intelligence, and many other astounding products of the human mind.

Indeed, by the end of the 20th century, nearly every 19th-century theory of natural and social phenomena would be overthrown or superseded.