David,you should include the info listed below,to make your guests more relevant.
Perhaps some folks on here are smart enough to go back 30 years.


In physics, spacetime (or space–time; or space/time) is any mathematical model that combines space and time into a single continuum. Spacetime is usually interpreted with space being three-dimensional and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions. According to certain Euclidean space perceptions, the universe has three dimensions of space and one dimension of time. By combining space and time into a single manifold, physicists have significantly simplified a large number of physical theories, as well as described in a more uniform way the workings of the universe at both the supergalactic and subatomic levels.

In classical mechanics, the use of Euclidean space instead of spacetime is appropriate, as time is treated as universal and constant, being independent of the state of motion of an observer. In relativistic contexts, however, time cannot be separated from the three dimensions of space, because the observed rate at which time passes for an object depends on the object's velocity relative to the observer and also on the strength of intense gravitational fields, which can slow the passage of time

David,you should include the info listed below,to make your guests more relevant.
Perhaps some folks on here are smart enough to go back 30 years.


In physics, spacetime (or space–time; or space/time) is any mathematical model that combines space and time into a single continuum. Spacetime is usually interpreted with space being three-dimensional and time playing the role of a fourth dimension that is of a different sort from the spatial dimensions. According to certain Euclidean space perceptions, the universe has three dimensions of space and one dimension of time. By combining space and time into a single manifold, physicists have significantly simplified a large number of physical theories, as well as described in a more uniform way the workings of the universe at both the supergalactic and subatomic levels.

In classical mechanics, the use of Euclidean space instead of spacetime is appropriate, as time is treated as universal and constant, being independent of the state of motion of an observer. In relativistic contexts, however, time cannot be separated from the three dimensions of space, because the observed rate at which time passes for an object depends on the object's velocity relative to the observer and also on the strength of intense gravitational fields, which can slow the passage of time

A couple of thousand years or so ago, the incommensurability of discrete numbers - not to mention the continuous physical magnitudes - essentially destroyed the Pythagorean cult, so to speak. Now in modern times, the incompatibility of the Discrete Theory of Matter, and the Continuous Theory of Spacetime, complicates and even threatens the theoretical community with a similar fate.

With the rise of so-called String Theory, hopes of reconciling Quantum physics with Continuous physics has arisen, only to inflate into a landscape of near infinite possibilities and, with that, the prospect of describing the physical laws of a concurrently unique and predictable universe diminished significantly. Even worse, our very notion of space now appears to be brought under examination for similar reasons.

This leads to the seemingly inevitable conclusion that both space and time, as we know them today, are “doomed,” as fundamental entities of theoretical physics. Since no one yet knows how to do Physics without time, Einstein's notion of Spacetime - more specifically, the dimension of Time in Spacetime - must have its validity questioned in the same way Pythagorean 'algebra' was examined (and eventually dismissed) as the basis for the science of Pure Time.

I guess.