For example, the human race had been founded on the belief that the earth is the center of the universe until Isaac Newton came forth with the idea of gravity. On the negative side, science is blamed for taking away crucial aspects of rational thought. On the positive end, science brings new ideas and makes contributions to human thoughts. Still, thanks in larger part to Arthur Eddington and his arrow metaphors, the question “which way is time going?” no longer sounds like total nonsense.The impact of science on human life remains an issue of contention among different groups of people. As for general relativity, treating time as a variable (rather than a constant) might help make the math work, but that doesn’t necessarily mean variable time is a real phenomenon. Of course a lot of people remain skeptical about time travel. So time’s arrow must always point in the direction of increasing entropy. That one exception is the second law of thermodynamics, which tells us that the entropy of a closed thermodynamic system will inevitably increase with the passage of time. But when you do the math, you’ll find that none of the laws of physics actually require time’s arrow to exist, except one.And common sense reasoning insists that time’s arrow must always point in the same direction.

Gosh, time’s arrow sure does seem real to us humans.

In 1927, in a series of lectures at the University of Edinburgh, and then later in a book titled The Nature of the Physical World, Eddington made three key points about time’s arrow, which I’ll paraphrase as: Depending on what sort of physics problem you’re trying to solve (or what sort of Sci-Fi story you’re trying to tell), it may be more convenient to imagine time’s arrow pointing from the future toward the past. Eddington’s arrow points from the past toward the future.

Physicists were writing laws of nature in a way that made time directionless, a mere change of sign separating + t from – t.īritish astronomer Sir Arthur Eddington gets credit for introducing the “arrow of time” as a conceptual metaphor. Millennia had gone by without scientists needing special shorthand like “time’s arrow” to state the obvious- the great thing about time is that it goes on. In his book Time Travel: A History, science historian James Gleick explains: And then in 1915, Albert Einstein started treating time as a variable, rather than a constant, as part of his general theory of relativity. Wells introduced the concept of time travel to the readers of adventure fiction. Why would anyone question it?īut then in 1895, H.G. Which way is time going? Prior to the 1890’s, no one would have asked such a silly question. Hello, friends, and welcome back to Sciency Words! Each week, we take a closer look at the definition and etymology of a science or science-related term.

Time's arrow time's cycle