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Why do we move forwards in time?

Why do we move forwards in time?

作者:鲜于寡睇  时间:2019-03-15 06:02:02  人气:

Gallery Stock By Michael Slezak THERE is a reason we say time goes by: it seems to flow. No matter how still we stand in space, we move inexorably through time, dragged as if in a current. As we do, events steadily pass from the future, via the present, to the past. Isaac Newton saw this as a fundamental truth. “All motions may be accelerated and retarded, but the flowing of absolute time is not liable to any change,” he wrote. So how does time flow, and why always in the same direction? Many physicists will tell you that’s a silly question. “The idea that time can in some meaningful sense be said to flow, it’s just a complete non-starter,” says Huw Price, a philosopher at the University of Cambridge. For time to flow, it must do so at some speed. But speed is measured as a change over time. So how fast does time flow? George Ellis, a cosmologist from the University of Cape Town, South Africa, has an answer: “One second per second.” Price says that’s meaningless. Even if time were standing still, it could be said that for every second that passes, one second passes. Indeed, if that’s a measure of flow, we could say that space flows: it passes at one metre per metre. Ellis is up against one of the most successful theories in physics: special relativity. It revealed that there’s no such thing as objective simultaneity. Although you might have seen three things happen in a particular order – A,