The NEAR spacecraft went into orbit around asteroid Eros on February 14,
Most of you will be aware of our NEAR challenge,
based on the exploded planet hypothesis. We predicted that the orbiting
spacecraft would find at least three currently orbiting moons, or (if the
gravity field is unstable) at least three former moons resting on the surface
after a grazing touch-down from a slowly decaying orbit. The latter, we
indicated, would be uniquely recognizable as former moons by roll marks that
would result from the 10 m/s horizontal velocity of a former moon at the point
of first touch-down. Friction is minimal in such a weak gravity field, so
rolling boulders should leave long, tell-tale linear tracks on the surface.
The gravity field did turn out to be mostly unstable. However, the very
first image of Eros from orbit, reproduced on the next page and available on our
web site, seems to show a linear track starting randomly on the asteroid’s
surface, then climbing up the outside wall of a crater, running down the inside
wall, ending at a 50-meter boulder near the crater center. Many people have
commented that this looks remarkably like what we predicted in the June 15, 1999
issue of MRB and illustrated by Starosta’s cover artwork on that issue.
Since that initial picture, dozens of additional trails, boulders, and trails
ending in boulders have been found on the surface of Eros. Surprised planetary
astronomers are now theorizing about boulders ejected from the interior of Eros
during collision events. But this ignores that the exploded planet hypothesis, a
model with a close-to-perfect record of successful predictions, also predicted
this phenomenon in advance of discovery. It also ignores that trails without
craters at their beginning, and going uphill from there, imply
considerable horizontal momentum for the boulders that made them. That can only
be true if they came from orbit. In view of these findings, we declare the
“NEAR challenge” won. However, what speaks even louder than another
for the eph is that no astronomer accepted our NEAR challenge despite it
being widely publicized.
photo of a large crater on Eros with a trail across
a crater rim, leading to an interior
as left, with portions of the trail and boulder
To his considerable credit, planetary astronomer Andrew Cheng, the
spokesperson for the NEAR team (operating from the Applied Physics
Laboratory instead of the Jet Propulsion Laboratory for a change), presented
evidence that Eros originated from “probably a planet-sized body that once
broke up”. Under questioning at a NASA press conference, Cheng explained that
little is known to constrain the parent body size, but that the current opinion
of most astronomers is that it was Moon-sized or smaller. This evidence for a
large parent body for Eros includes:
geological layering, which could not have been created directly on the
asteroid because its escape velocity is so low, and material from any impact big
enough to create layers would therefore escape.
diversity of composition, showing major spectral differences over the
surface, and even within single craters.
evidence of chemical differentiation, which implies near-total melting
sometime in the past with consequent separation of heavy and light elements by
gravitational sorting – things usually associated with planets.
solidness implied by the density, as contrasted with the sort of rubble
pile expected for an object formed by repeated impacts.
gradually, a recognition of the eph as a necessary ingredient to explain solar
system history and evolution is getting around. Even the UPI coverage of the
NASA press conference was kind enough to mention our prediction.