Re: Does time have properties of a particle?

Hello Jim,

1) No, time is not particle-like in any way. Time is a dimension, one of the ways of specifying where "in space-time" to find something. For example, you can find the event "Ben sitting at his computer answering MadSci questions" at about -70 degrees latitude, 42 degrees longitude, 30 feet above sea level (three-dimensional space), at 5:30 PM on January 6 (one-dimensional time). Particles are just things that exist at move around and interact within these four dimensions.

2) An object moving through spacetime does distort the space around it. This is described by Einstein's theory of General Relativity. GR is a very comprehensive set of laws that describe space and time, and how they are distorted by matter and energy. The most obvious "distortion" is already familiar to you - it's gravity, the force holding you on the ground. There is also a minor effect called "frame dragging" caused by rotating objects. This could perhaps be viewed as a sort of "wake" effect. An essay on it is here, and an experiment trying to measure it is one called Gravity Probe B.

However, there should be no similar effect for a moving-but-not-rotating object. Here's a thought-experiment to illustrate: Imagine that astrophysics adventures Sally and Bob take a trip to the mysterious fast-moving Planet X to measure its gravitational effects. When they get there, Sally passes "in front" of the planet, hoping to measure its "bow shock", and Bob goes behind to measure the "wake". Before looking at the results, they land on Planet X and describe the experiment to the locals.

"What are you talking about?" says General X'llgargg, "Planet X has no wake, because we are sitting still. Your Earth is moving very fast towards us, actually, and we have sent Q'Bobbge and V'Sallyhiwzq to measure your wake." At the same time, two physicists arrive from even-faster-moving Planet Bloop, and from the Bloop point of view, they expect Planet X to have a wake on the opposite side than Sally and Bob predicted.

Do you see the problem? Who is right? Are the speedy X'ians moving towards the stationary Earth, or vice-versa? Which one actually has a wake? The answer is nobody: nobody has a wake, because their "motion through space" is only defined with respect to a particular observer. This is the idea, which is quite explicit in GR, that "all inertial reference frames are equivalent". Any object moving through spacetime under the influence of gravity and nothing else cannot tell, by measuring its own environment, whether it is "moving" - any sort of "wake" would violate this rule. That's why they call it "relativity" ... motion is only defined relatively, with respect to a particular observer.

Hope this helps! You can learn more about relativity elsewhere on MadSci, try doing a search for it.

-Ben V'hgjkzxc Monreal