Catastrophic Events
in the
Solar System
There are records in the surface and interior of
the planets and their satellites that indicate the
occurrence of VERY LARGE impacts that have
drastically altered the character of the solar
system. These events are unpredictable and not
adequately accounted for in the standard model
of planet formation (Solar Nebula Theory).
Catastrophic Events: Earth
• The formation of the Moon is now accepted to be
due to a grazing collision of a Mars-sized planet
with the early Earth after the Earth’s core had
formed (Step 6 in the standard model). The
collision destroyed the impacting planet and the
ejecta re-accreted to form the Moon.
• The moon has three important physical properties
that any formation scenario must predict.
First, the
density of
the Moon is
3.3 gm/cm3,
substantially
less than the
Earth’s bulk
density, but
similar to
the density
of the
Earth’s crust
and upper
mantle.
Second, Moon
rocks are
depleted in iron.
There is much
less iron in
Moon rocks than
in the rocks
found on the
Earth’s surface.
Third, Moon rocks are devoid of bound water. Even
meteorites have up to 5% water bound into the mineral
structures. The Moon has no water in its rocks.
The Hypothesized Collision that Formed the Moon
A Marssized planet
on a grazing
collision
course with
the Earth.
Earth after
its iron core
has formed
The Hypothesized Collision that Formed the Moon
Whamo!
Crust and
upper mantle
material is
ejected into
Earth orbit
The Hypothesized Collision that Formed the Moon
The iron core of
the impacting
body does not
escape but falls
back into the
Earth to join the
Earth’s core.
The Hypothesized Collision that Formed the Moon
The lighter
material from
the Earth’s crust
and mantle has
been heated so
much during the
impact that the
bound water has
vaporized and
escaped.
Earth’s
new MoonCollision
has formed
the iron
The
Hypothesized
thatfrom
Formed
thepoor
Moon
and dried out crust and upper mantle rocks of the
Earth and its impactor.
Interior
of the
Moon
Notice the
relatively small
iron core
Venus
Mercury
Moon
Earth
Mars
The Moon’s relatively small iron core bulk geology are consistent with a birth by a violent collision
The Moon
preserves a
record of
catastrophic
events itself.
This multiring impact
basin on the
Moon is
called Mare
Oriental.
The impact portrayed in this artist’s impression is far
smaller than the impact that created our Moon.
The currently accepted scenario for the Moon’s
formation would not have been possible with the
aggressive exploration of the Moon and other planets.
Ganymede is a natural satellite the size of Mercury.
Its surface preserves the evidence of a giant impact
that formed this multi-ring basin called Vahalla.
Recent impact craters reveal the clean ice that makes
up most of this moons mass.
This small
natural
satellite
called
Miranda has
surprising
surface
features for
an object its
size (236 km
radius).
Miranda has
both ancient
cratered
terrain
indicating
great age
and an
unusual
“chevron”terrain that
indicates
recent
resurfacing.
This Voyager image
of Triton hints at
the satellites violent
past. Notice the
two distinct terrains
and the lack of
impact craters. The
capture event
created enough
energy to
completely melt the
satellite erasing
previous ancient
craters and creating
a new terrain.
Cantaloupe-terrain
Few Craters and Ice
Volcanoes-terrain
This type of terrain is unique in the solar system. The
lack of craters implies a relatively young age of this
surface.