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Re: Meteorites from Earth and Venus
WBranchsb schrieb:
> How are these percentages derived?
MELOSH H.J. et al. (1993) Swapping rocks: Ejection and exchange of
surface material among the terrestrial planets (Meteoritics 28-3, 1993,
A398, Excerpts):
... we examined the orbital evolution and ultimate fate of ejecta from
each of the terrestrial planets. This work employed an Öpik-type orbital
evolution model in which both planets and ejected particles follow
elliptical orbits about the Sun, with uniformly precessing arguments of
perihelion and ascending nodes. An encounter takes place when the
particle passes within the sphere of influence of the planet. When this
occurs, the encounter is treated as a two-body scattering event, with a
randomly chosen impact parameter within the sphere of influence. If the
impact parameter is less than the planet's radius, an impact is scored.
Otherwise, the scattered particle either takes up a new Keplerian orbit
or is ejected from the solar system. We incorporated several different
space erosion models and examined the full matrix of possible outcomes
of ejection from each planet in random directions with velocities at
great distance from the planet of 0.5, 2.5, and 5.0 km/s. Each run
analyzed the evolution of 5000 particles to achieve sufficient
statistical resolution. Both the ultimate fate and median transit times
of particles were recorded.
> Which brings to mind another interesting possibility.
V e r y interesting Walter!
Regards, Bernd
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