Hi Everyone,

Jorrie wrote:Yea, I regret having mentioned the "larger spacetime structure", because it is irrelevant here. As I have explained to Dave_O, it only enters the fray when we consider general relativity at cosmological scales.

This is where Jorrie and I may start a debate. I would say this Space-Time structure exists at every level of Scale, from the Biggest to the Smallest. It doesn't magically appear at some preset super size.

Of course this Space-Time stuff is what is called an Aether. It's just as Real as a Magnetic Field. You can't see it or smell it or taste it.. but you can tell the Magnetic Field is real by pushing a Magnet around with another Magnet, without them touching each other.

If you want to bounce back to page one for a moment:

http://sciencechatforum.com/viewtopic.php?f=10&t=32778&start=0#p320369My argument comes from the idea of Curved Space-Time. You can't have a curvature unless there is something real that can be curved.

See, Jorrie is a Purist. They will say that the only thing Real is the Math that describes the Relationships within Relativity such as Matter, Speed and Clocks etc. That anything outside of what the Math tells us is pure Speculation.

This is completely true and Jorrie is completely correct. No argument there.

But many times, it can be easier to get an idea across if one offers a Model that is just a speculation or an Analogy. For the purpose of teaching something, such Analogies can prove very useful, even if they are not completely accurate. For many of us, the Purist view is nearly impossible to wrap ones mind around, unless you are another Einstein.

Even Einstein had no clue what Space-Time really is. But it is a useful tool for trying to imagine how things work with each other. So, for those of us that want a simple "Meat and Potatoes" view, I believe such speculative Models can serve a useful purpose in teaching those of us that fall short of being Einstein Clones.. lol.

So, if Jorrie will allow me this leeway, I'll propose explanations that translates reasonably well to what Jorrie is teaching, but is much more simple to understand. Just keep in mind that any such Model may be completely wrong, especially from a Purists point of View.

This is why I suggested that Alice and Bob had a race that started at the same time and ended at the same time. But Alice took a much longer scenic route and was traveling a lot faster than Bob to do so. So why did Alice age less than Bob? Could it be she passed through a lot more Aether Space-Time than Bob at a much greater speed than Bob? That would be the truth.. if we took the Race at face value. Did the structure of Alice change in a different way than the structure of Bob during the race? A change that caused Alice to age slower than Bob? Did flying though a lot more Space and much faster really change her Physical Structure?

My Race is different than what Jorrie had proposed. In his version, Alice had to speed up, fly away, slow down, turn around, speed up again and return to Bob while slowing down to rejoin Bob. And she still aged a bit less than Bob. Jorrie's point was that if we graphed out this scenario, that the Accelerations and Decelerations would look like Curves on the Graph, where the straight lines are when Alice was coasting.

The straight lines indicate that during that part of the trip, Alice continues to Age slower than Bob for as long as she keeps going without changing speed. If she did this long enough, such that the curved part of the graph is only a small part of the whole, that when she got back, Bob could have died of old age while Alice is still a spring chicken (so to speak).

That Epstein Graph Jorrie showed on page two is not really that scary. It is just a graph of Bob and Alice laid on top of each other (no incest intended). It shows Time (top/bottom) and Speed (left-right). If you rotate both to point straight up, then they are not moving and both are aging at the same rate. If you rotate both Red and Blue Graphs the same amount, then both are moving at the same speed and aging at the same rate as each other.

If you rotate one graph (Red one) more than the Blue one, the graph shows how each one is aging differently then the other. The exact ratio in aging is marked with a big fat Red Dot marked (1). This is showing how much Alice's clock is changing compared to Bob's clock. You may even notice that if you rotate the Red and Blue the same amount, but in opposite directions (one clockwise and the other counter-clockwise), that Alice and Bob are heading away from each other but at the same speed. So they would both have clocks ticking at the same rate as each other and, of course, they would be aging at the same rate.

*Epstein Spacepropertime*

Note: I asked Jorrie if I rotated the big red dot to the 3:00 position what would it tell us? He said I can't, because that would have Alice moving at the speed of light and her clocks would be stopped completely.

I hope I didn't muddle this all up about the graph above.

Ok, I have to get back to work.. catch everyone later.

Regards,

Dave :^)