On Apr 9, 9:57*pm, Cecil Moore wrote:
Keith Dysart wrote:
That is why I pose the question, hoping for someone to
describe the mechanism that the energy for the flow that
is happening now can be borrowed from the future.

Destructive interference would have to happen first.

For the example under discussion, the signals start with
'constructive interference'. There has not yet been an
opportunity for desctructive interference, which happens
later. So where does the extra energy at the start come
from?

But what happens if the generator is turned off before
the future arrives? Where did the extra energy come from
then?

There is no extra energy. Constructive interference is
impossible without that supply of energy.

Exactly. This is the problem with your model. The extra
energy (i.e. the energy greater than that in the sum of
the spectral components) is present, but your model does
not have somewhere for this energy to come from.

Actually, I have a pretty good grasp of what is happening
in free space, and it is all available to you by extension
from the behaviours of the one dimensional transmission
line. But there is little point in going there until the
transmission line is understood.

It is the exact opposite. There is no point in inventing
new laws of physics for transmission lines if those new
laws don't work in free space.

There are no new laws of physics. There is just the
opportunity for a better understanding of what is
happening. This better understanding applies in free
space as well. It is just much easier to obtain this
better understanding on the transmission line and then
move to free space.

So please present an example of EM waves reflecting off
of other EM waves in free space.

That was someone elses suggestion, not mine.

Do you really think the
energy in the standing wave beam of a laser is reversing
direction and momentum every cycle?

Why does this thought make you uncomfortable? Is it because
you are trying to commingle the wave explanation with the
partical explanation? These are a duality. You use one
or the other, but not bits from each at the same time.

...Keith