Berlitz, Charles. The Bermuda Triangle. Garden City: Doubleday, 1974.
Berlitz, Charles. Without a Trace. New York: Ballantine Books, 1985.
Twain, Mark. A Connecticut Yankee in King Arthur’s Court. Oxford Oxfordshire: Oxford University Press, 1996.
 

Robert Heinlein’s 1941 story “By His Bootstraps”
Robert Heinlein’s 1957 novel “The Door Into Summer”
Robert Heinlein’s 1959 story “All You Zombies”
Robert Heinlein’s 1973 novel “Time Enough for Love”
Robert Heinlein’s 1980 novel “The Number of the Beast”
Robert Heinlein’s 1985 novel “The Cat Who Walks Through Walls”

Rip van Winkle (1819) Washington Irving
The Clock That Went Backward (1888) Edward Page Mitchell
A Connecticut Yankee in King Arthur’s Court (1889) Samuel Clemens [Mark Twain]
The Time Machine (1895) H. G. Wells

Science-fiction authors have had various uses for time machines, including dinosaur hunting, tourism, visits to one’s ancestors, and animal collecting. Ever since the time of H.G. Wells’ famous novel The Time Machine (1895), people have grown increasingly intrigued by the idea of traveling through time. (I was lucky enough to have chats with H.G. Wells’ grandson, who told me that his grandfather’s book has never been out of print, which is rare for a book a century old.) In the book, the protagonist uses a “black and polished brass” time machine to gain mechanical control over time as well as return to the present to bring back his story and assess the consequences of the present on the future.

Wells was a graduate of the Imperial College of Science and Technology, and scientific language permeates his discussions. Many believe Wells’ book to be the first story about a time machine, but seven years before 22-year-old Wells wrote the first version of The Time Machine, Edward Page Mitchell, an editor of the New York Sun, published “The Clock That Went Backward.”

One of the earliest methods for fictional time travel didn’t involve a machine; the main character in Washington Irving’s “Rip van Winkle” (1819) simply fell asleep for decades. King Arthur’s daughter Gweneth slept for 500 years under Merlin’s spell. Ancient legends of time distortion are, in fact, quite common. One of the most poetic descriptions of time travel occurs in a popular medieval legend describing a monk entranced for a minute by the song of a magical bird. When the bird stops singing, the monk discovers that several hundred years have passed. Another example is the Moslem legend of Muhammad carried by a mare into heaven. After a long visit, the prophet returns to Earth just in time to catch a jar of water the horse had kicked over before starting its ascent.

Newton’s most important contribution to science was his mathematical definition of how motion changes with time. He showed that the force causing apples to fall is the same force that drives planetary motions and produces tides. However, Newton was puzzled by the fact that gravity seemed to operate instantaneously at a distance. He admitted he could only describe it without understanding how it worked. Not until Einstein’s general theory of relativity was gravity changed from a “force” to the movement of matter along the shortest space in a curved spacetime. The Sun bends spacetime, and spacetime tells planets how to move. For Newton, both space and time were absolute. Space was a fixed, infinite, unmoving metric against which absolute motions could be measured. Newton also believed the universe was pervaded by a single absolute time that could be symbolized by an imaginary clock off somewhere in space. Einstein changed all this with his relativity theories, and once wrote, “Newton, forgive me.”

We are a moment in astronomic time, a transient guest of the Earth. Our wet, wrinkled brains do not allow us to comprehend many mysteries of time and space. Our brains evolved to make us run from saber-toothed cats on the American savanna, to hunt deer, and to efficiently scavenge from the kills of large carnivores. Despite our mental limitations, we have come remarkably far. We have managed to pull back the cosmic curtains a crack to let in the light. Questions raised by physicists, from Newton to Kurt Gödel to Einstein to Stephen Hawking, are among the most profound we can ask.

Is time real? Does it flow in one direction only? Does it have a beginning or an end? What is eternity? None of these questions can be answered to scientists’ satisfaction. Yet the mere asking of these questions stretches our minds, and the continual search for answers provides useful insights along the way.

from:Traveling Through Time
by Clifford Pickover