Re: Is space and time discontinuous like matter and energy?

Lon,

You might find this amusing: I did a web search on "chronon" and found it as

• the name of a computer company
• a word in biblical Greek (it shows up in the New Testament)
• the name of an evil overlord in a video game
• a technical term in music theory
• and, oh yes, a measure of the smallest unit of time

Anyway, on to your question. The idea that time and space may be discrete instead of continuous is not a new one -- Zeno's paradox is a good example of this in historical thinking. The advent of quantum mechanics in this century, and with it the realization that things like energy and angular momentum are quantized, brought the idea of time and space quantization back into vogue. I think it's a good guess that the "Theory of Everything" that combines general relativity and quantum mechanics (the Holy Grail of theoretical physics) will need to include time and space quantization somehow.

There have been many attempts to understand how this quantization might work, and the article you read was probably a desciption of one of these. As far as I can tell, there is no consensus on the "correct" answer -- it's an active area of research. Here is an article that discusses some of the work to date; be warned that it's pretty technical. (Another warning: some of the "physics" you find on the WWW comes from crackpots! This article comes from a reputable institute, so it's likely OK).

There is one thing we do know about time and space quantization: there are time and length scales below which quantum mechanics breaks down. These are the Planck length (1.7e-35 m) and the Planck time (5e-44 s). Current quantum theory can't go past these limits, but the "Theory of Everything" will have to explain why they're there and whether or not they are the fundamental units of space and time.

For more imformation on this, you might check out Brian Greene's book "The Elegant Universe", on superstring theory (the theory that might be the aforementioned "Holy Grail"). Many popular books on quantum mechanics will also give you a feeling for the subject.

Pauline