***{Does anyone have an explanation for the following? --MJ}***

Forwarding permission was given by William R. Corliss

http://www.science-frontiers.com

SCIENCE FRONTIERS, No. 159, May-Jun 2005, p. 4


GEOPHYSICS

Extreme LDEs

LDEs (Long-Delayed Echoes) are heard fairly often by radio hams. Usually,
their signals are reflected back to them delayed by just a few seconds. But
since radio waves travel 186,000 miles/second, any reflector must be located
far beyond the moon's orbit. Question: what's out there?

LDEs have been recognized and puzzled over since 1927. (SF#10, SF#39)
But so far no completely convincing explanation has been forthcoming. Three
ideas thrown on the table have been:

* Multiple trips of the signal around the world with the ionosphere's help.

* Signal trapping in ionospheric ducts.

* Reflections from distant plasma clouds.

Most LDE research has been carried out by radio hams, who have now
discovered a new twist to the LDE puzzle: some LDEs return not in
just a few seconds but in minutes and even hours! Can you imagine
a radio reflector a light-hour distant? After all, the sun is only 8
light-minutes away.

Japanese hams have been at the forefront in collecting these extremely long
LDEs. M. Obara, in Tokyo (call letters TZ6JA), summarized the situation
as follows.

All of these records (except UL7GW) indicate very long delay
times ranging from 20 minutes to 82 hours. Converting these
times to distances...corresponds to round trips of 1.8 - 297 AU
(Astronomical Unit, 1 AU = 150 million kilometers, or about
93 million miles, the distance between the Earth and the Sun).
These delay times suggest the existence of two hypothetical
*interplanetary ionospheres*, composed of numerous magnetic
and plasma tails of small planets and debris, located mainly at
the minor planet belt (asteroid belt) and the Kuiper belt (a
region beyond Neptune containing thousands of small bodies
orbiting the sun that is believed to be the spawning ground
of many short-period comets.

(Obara, Mac; "Long-Delayed Echoes: Reflections from an Ionosphere in
Space?", *CQ*, 24, Feb 2005. Cr. L.M. Nash)


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