Here’s one for the Velikofsky fans…

From: nev@[somewhere].com
Subject: alt.pave-the-earth
To: nev@[somewhere].com
Date: Wed Jul 1 11:05:01 1998 -0700

Let us imagine the Moon has almost magically been lowered gently to a
kissing contact with the Earth, in the centre of the Pacific, on the
Equator. Then let the controlling forces let go, and let’s watch the
results from a safe distance….

Loose material on the limbs of the Moon, like Moondust, rocks, Apollo
spacecraft, and even whole mountains will experience a gravitational
attraction sideways towards the Earth of 62% of g at Earth’s surface.
Meanwhile, Moon gravity remains at 1/6 g sideways into the Moon. The
nett effect is that everything not glued down will fall off the sides
and underneath of the Moon, but being gently focussed inwards as it
drops. It will take over seven minutes just to fall from a height of
1738 km (the Moon’s radius), dodging the occasional satellite in low
orbit that will smack into the debris cloud. At impact, downwards
velocity will be over 5km/sec. While not of totally cosmic
proportions, this is a significant re-entry speed. Small debris will
tend to burn up in the atmosphere, yet so much debris will be falling
that the atmosphere will be compressed and displaced. Small primary
impact craters will result from the impact of bodies larger than 10m
or so.

Not just the loose material will fall. The sideways (shear) force will
be enough to tear off the Moon’s crust and Mantle. The strength of
rock is almost irrelevant given the forces involved. If we imagine the
Moon as a cylinder, for a moment (and it will rapidly flatten
downwards towards the Earth into some sort of squashed pear-shaped
blob), it has a cross sectional area of pi * radius^2 or 3.02 * 10^12
square metres. Its Mass is some 7.35*10^22 kg. Correcting for the
decay of Earth’s gravity field, there would be a force of 1.5*10^10
kgf per square metre (15 million tonnes), or 15 tonnes per square cm
(atmospheric pressure is around 1kg per square cm). Hydraulic presses
on Earth do wonderful things to steel at those sort of pressures.

It won’t just be the Moon that deforms. The Earth will be indented by
this mass, “locally”. Outside of the dent, a bulge or bow wave will be
thrust up. This wave will propogate out at seismic wave speeds in the
Mantle of around 8 km/sec, forcing the seabed up to meet the falling
debris, adding to the collision speed. The atmosphere and oceans will
be blasted out sideways, as a hypersonic shock wave develops in a
torus round the merge point.

Meanwhile, on the other side of the world, the oceans of the world
will experience the Mother of all Tides. To first Order, the centre of
gravity of the Earth-Moon system will be displaced towards the Moon by
the ratio of masses i.e. 1/81 of their separation (8000 km) =
100km. The equipotential surface of the joint body will therefore be
100km above sea level in the Pacific, and 100km below it at the
antipodal point (about the middle of Africa). The seas will pour
bodily sideways in a cataclysmic tidal wave, mounting up into
kilometres high tsunami that will rush bodily inland. Central America
will be overwhelmed like a broken straw, and the Atlantic will surge
across the USA all the way to the Rockies. Of course, this would take
many minutes, or perhaps a few hours.

The tidal wave wouldn’t get that far before the outgoing shock wave
arrives from the Pacific, like a a huge “plop” as a stone falls into a
pond. The surface wave (literally, a wave of the Earth’s suface, and
crust, and mantle….) would be tens to hundreds of km in amplitude,
totally disrupting the crust. Every volcano on Earth would erupt
cataclysmically as their magma chambers were torn open and exposed to
the surface, but they would be the merest fart in comparison to the
effect of the wave itself.

As the Moon was sucked into the Earth, a huge molten droplet could be
thrown back upwards, like those beautiful “milkdrop in a cup of
coffee” photos. This would “only” be 500km in radius and probably
wouldn’t make escape velocity, but it would splash nicely when it came
back down again. Smaller pieces in the 1-100km range would be blasted
sideways and upwards in ballistic trajectories to fall back in
secondary impacts right around the globe. A debris cloud would orbit
the Earth, but would rapidly be winnowed as lumps going one way met
those going the other. Most of the debris would fall back to Earth on
a time scale of years to centuries, but the Earth’s dust rings would
be a beautiful sight for any visiting spacefarers.

The Earth itself would be in turmoil. It would wobble like a jelly for
days, and ring like a bell for months or years. The Oceans would boil,
and the atmosphere could be significantly lost to space. Life would be
wiped clean from the planet.

Perhaps (if there is any justice) the last human to be blasted with
incandescent gas would be our friend AP who might possibly say “It
wasn’t supposed to do that!”

On a longer timescale, the site of the merging would be a boiling hell
of lava 5000km across for millenia. The entire tectonic and convection
system of the Earth would be disrupted. Remember that the Moon is made
of relatively low density rock, like Anorthosite (rich in feldspars,
like Earthly granite is, but much more so). The Moon is probably made
of much of the primordial crust of the Earth, blasted off in a major
impact billenia ago. Finally it would have returned. The Moon has
enough volume to spread out in a layer around 50km thick across the
whole Earth – More than double the current volume of the Earth’s

Like Venus, some 500Ma past, the entire surface of the Earth would be
recycled. The plate tectonic process would start again almost from
scratch and begin to sort mixed up crust from mantle, aided by the
energy input to the Earth that would raise its global temperate a fair
bit towards the liquidus (total melting point). There would be enough
energy liberated by this collision to raise the temperature of the
entire volume of the Earth by over 100 degrees Centigrade. Fluid
magmas like the precambrian komatiites would gush out of every crack
and fissure in the shattered Earth, flooding its surface with basalts.
Gradually, the remnants of the crust would clot together like scum on
a boiling pot and the continents would begin again as felsic islands
surrounded by ferociously active greenstone belts and mobile zones.

Who knows, perhaps in about 2 or 3 billion years that organic soup
could start again and give rise to new generations of geologists and
astronomers to wonder at the heavens and discover the History of the
Earth, but it would be a different planet than now:- Slightly larger,
with no Moon, no Tides, Thick crust like Mars, but active volcanism
like Venus.

– Nick Hoffman, Geophysicist Extraordinaire

Home, home on Lagrange

There have been rumours floating about for some time now that President Bush is going to annouce some major space policy sometime soon.

Buzz Aldrin weighs in with a proposal for a STS-based heavy-lift vehicle (basically Shuttle-C, I guess), and a station at L1.