Traveling Through Time

Photo credit: © RTimages/iStockphoto  By Clifford Pickover  NOVA

What is time? Is time travel possible? For centuries, these questions have intrigued mystics, philosophers, and scientists, and the subject of time has been central to the world’s many diverse religions and cultures. Here, futurist Clifford Pickover looks at the history of the baffling concept of time and explains why we shouldn’t discount the possibility of traveling through it.

We have an everyday sense of time, but what exactly is it? The question is as hard to answer as whether or not time travel will ever be possible.

Can the flow of time be stopped? Certainly some mystics thought so. Angelus Silesius, a sixth-century philosopher and poet, thought the flow of time could be suspended by mental powers:

Time is of your own making;
its clock ticks in your head.
The moment you stop thought
time too stops dead.

The line between science and mysticism sometimes grows thin. Today physicists would agree that time is one of the strangest properties of our universe. In fact, there is a story circulating among scientists of an immigrant to America who has lost his watch. He walks up to a man on a New York street and asks, “Please, Sir, what is time?” The scientist replies, “I’m sorry, you’ll have to ask a philosopher. I’m just a physicist.”

time’s past

Most cultures have a grammar with past and future tenses, and also demarcations like seconds and minutes, and yesterday and tomorrow. Yet we cannot say exactly what time is. Although the study of time became scientific during the time of Galileo and Newton, a comprehensive explanation was given only in this century by Einstein, who declared, in effect, time is simply what a clock reads. The clock can be the rotation of a planet, sand falling in an hourglass, a heartbeat, or vibrations of a cesium atom. A typical grandfather clock follows the simple Newtonian law that states that the velocity of a body not subject to external forces remains constant. This means that clock hands travel equal distances in equal times. While this kind of clock is useful for everyday life, modern science finds that time can be warped in various ways, like clay in the hands of a cosmic sculptor.

Today, we know that time travel need not be confined to myths, science fiction, Hollywood movies, or even speculation by theoretical physicists.

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.”

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