Sunday, October 5, 2008

A Stubbornly Persistent Illusion

The Large Hadron Collider (LHC), in addition to giving this blog its name, will (when it's turned back on) send particles hurtling into the future. Many particle accelerators are now, from the perspective of the particles, performing time travel. Einstein's relativity promises that at extreme speeds (close to the speed of light) and extreme gravities (such as those near a black hole) time-space is meaningfully warped. Something travelling extremely fast (protons in the LHC will move at 99.99% the speed of light) experiences time more slowly. Particles in the LHC will therefore travel into the future, at least in relation to us.

The practical implications for you and me are somewhat limited at the moment. A time machine is not right around the corner. But the philosophical implications are stunning. The truth of physics is at odds with our meager perceptions of the world. Our notion of time - seconds always receding - is not reality. As Albert Einstein famously remarked on the death of a friend:
Now he has departed from this strange world a little ahead of me. That means nothing. People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.
Physics does not distinguish past, present and future in the ways we do. Relativity exposed fixed time as a contrivance, quantum mechanics suggests, amazingly, that time may not exist at all. Our bias for the present is, as Einstein said, an illusion. I find that idea incredibly reassuring. I think about my Grandma, gone almost 5 years, and imagine her comforting me as a child. Or I think about the greatest day of my life, the day my son was born. In some sense, those events are happening now, happening forever.

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