May 23, 2007
Impacts that "hit the bull’s eye" of a previous impact
are "high-odds" improbable. But lightning—even planet-scale
lightning—can strike twice in the same spot.
One of the
principal claims of the Electric Universe model is that many
features on the surfaces of rocky bodies are scars left by
electrical activity. A crater is produced when an electrical
arc, consisting of two or more Birkeland currents rotating
around a central axis, “sticks” to one location and “drills
out” a circular depression.
electrical forces constrain an arc to strike a surface at a
right angle, the crater will tend to be circular. Because
the forces are distributed cylindrically, the crater will
tend to have steep sides and a flat floor. Electrical forces
lift debris from the surface, leaving no rim or a rim of
“pinched-up” material. The properties of flat floor, steep
edge, and removal of debris are why electrical etching has
been developed into the industrial process of electrical
discharge machining (EDM).
rotating currents do not touch at the central axis, they
will leave a “peak” of undisturbed material. A sudden change
in current or in current density, due to pinching forces in
the arc or to the influx of charge-carrying debris, may
cause the arc to “shrink” to a smaller diameter, leaving a
terrace around the wall. Because the arc is maintained for
an appreciable time by a continuous electrical current,
melting of surface materials may be extensive.
contradistinction, craters formed by mechanical impact tend
to have rounded floors and rims. Because the forces are
distributed spherically, debris is thrown out of the crater
ballistically and deposited radially in a gradation of
fineness and volume. The energy of the impact is dissipated
in shock displacement of material: solids will “flow” as if
liquefied and suddenly “freeze” when the impulsive force
drops below a threshold. Very little melting occurs.
inspection of rocky-body craters discloses their conformity
craters in the above image are a variation on the EDM theme.
They display the typical flat floors, steep sides, and
pinched-up rims. They have terraces around their walls. But
instead of central peaks, they have central craters. Two
more craters that are similar lie to the southwest.
colleague Michael Mirkin, in pointing these craters out to
us, has christened them “bull’s-eye craters,” in reference
to the middle concentric circles of a dart board,
emphasizing the difficulty of hitting the precise center
impact interpretation, central craters could only be caused
by a second impact that coincidentally struck exactly in the
center of the previous impact. The impactors that created
the craters would have to hit a perfect “bull’s eye” to
create this effect. It might happen once. Twice in close
proximity is extremely unlikely. But four times in the same
neighborhood stretches the meaning of “coincidental” beyond
the covers of the dictionary.
If the arcs
that machined the large craters persisted until they pinched
down into a very small diameter, or if a second return
stroke followed the ionized path left by the first and
persisted long enough, the central peaks (if they were not
already machined away) would have been “drilled down,”
perhaps even to a depth below the original craters’ floors.
Such an event would not be the norm, but several “bull’s-eye
craters” in a particular area would not be surprising. It
may be significant that the four examples noted here lie on
the plain just south of Valles Marineris, the largest EDM
channel (from a traveling arc) in the Solar system.
Martian Butte and Crater,
Domed Craters on Mars
Contributed by Mel Acheson
The Electric Universe