[meteorite-list] Venus Catastrophic Resurfacing HypothesisChallenged

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Mon, 26 Apr 2010 01:50:32 -0500
Message-ID: <2957203A17934CDE9C81198FC03298AF_at_ATARIENGINE2>

Listoids and Venus Fans,

    The Global Catastrophe "Hypothesis" became a problem
as soon as the Magellan dataset was mostly complete. The
data was turned over to the "crater-counters" who are able
to date a planetary surface by the statistical distribution of
crater size, and date it quite precisely, too.

    When they announced the age of the Venusian surface
as 520 million years, plus or minus a 40-50 million year
error (or 480 to 560 my), they were immediately surrounded
by hysterical geologists screaming that they had to be wrong.

    The crater counters were replaced by other crater counters
who gave the same results. This is a narrow specialization --
crater counting -- there are only so many crater counters,
and it's a very precise technique that has dated every solid
planetary surface we can image with results that are both
consistent and to every appearance accurate everywhere.

    A decade or so was wasted on "geological" mechanisms
that could re-surface without outside interference. They
were largely hooey that convinced no one, posing improbable
mechanisms to accomplish world-wide simultaneous subduction.
The problem is not a "hypothesis" problem; it is a "fact" problem
looking for a hypothesis.

    If we take a step backward and look at events in the
ENTIRE solar system, we see that:

a) ~600 million years ago, the largest asteroid breakup
in the last 4 billion years occurred (the Flora Family),

b) starting at 600 million years ago, the impact rate in
the solar system jumped up to high levels not seen
for 3.2 billion years (dated by lunar impact spherules
collected by the Apollo missions),

c) between 600 million years ago and 500 million years
ago, the Earth had three catastrophically nasty ice ages,
including the Snowball Earth episode in which the entire
planet froze to the equator, the worst ice age ever,

d) 484 million years ago, the Earth suffered a prolonged
period in which the rate of meteoritic infall was up to 150
times greater than it is today,
http://www.psrd.hawaii.edu/Mar04/fossilMeteorites.html
and

e) the surface of Venus was wholly or partially melted and
resurfaced with fresh rock (just like the old days, huh?).

    I see these events as connected, as I've been sometimes
posting here for the last 6 or 7 years. Or, they could be one
freakin' big coincidence...

    So, I read the RTT paper with great interest. They advance
solid arguments for the conclusion that the RTT had to be
formed in one discrete episode or interval. In a word, that
it's datable. They then assert that it had to have formed very
early in the planet's history because "thermal modeling
indicates that ribbon fabric formation requires an extremely
high thermal gradient..." That is, a high internal heat flowing
up to the crust as it does at the end of planetary formation
and cooling. In other words, you can't form RTT unless the
crust is very hot. That is the extent of their "dating" attempt.

    The ancient origin would be true in the case of the absence
of a viable geological "catastrophic" or global turnover model
ONLY IF you exclude impacts (giant or multiple) large enough
to melt the crust down to the mantle. Best way to prove your
case is to ignore anything that would disprove your case,
I always say.

    The RTT are scattered in disconnected patches over the
planet. They could be a relict of ancient terrains or they
could be the places where the 100-300-kilometer asteroids
DIDN'T fall. The fall of planetoid sized bodies, of course,
heats the crust planet wide by degrading the impact energy
into thermal energy. The heat doesn't have to be internal
when you melt a planet's surface.

    Hansen and Lopez have another paper on the RTT,
characterizing them as lava "scrum ponds," also from
this same year (2009):
http://www.lpi.usra.edu/meetings/venus2009/pdf/2012.pdf
(I think you ought to hold it down to one theory a year.)

This is a strange idea since the RTT is 1-3 km. HIGHER than
the low flat plains -- why didn't the lava run off? But, then,
I'm no geologist and I don't really know how to make lava
run uphill... How you do dat? In fairness, a few RTT parches
are on the lowest level... but only a few small ones.

    Another view on the RTT by another member of the
original Magellan team (this one from 1996):
http://www.agu.org/pubs/crossref/1996/96JE01245.shtml
Author of many papers on Venus; Google "Ivanov Venus."

    There's another theory of the RTT, the "pulsating
continent" theory. Bouncy continents... That sounds
like fun:
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V61-4TRR8Y0-1&_user=10&_coverDate=11%2F30%2F2008&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1310409062&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=1a74f8614c1c46478bfbfe77b807a05a

    There seems to be this continuing effort in explaining
Venus' geology by "mechanisms without outside interference."
I'm tempted to see it as the old "we're-geologists---take-your-
asteroids-and-never-darken-my door-again." The dinosaurs
died off from bad head colds... Didn't you know?

    The "Mega-Catastrophe" paper from 2 years ago (which IS
an impact paper) is by Huw Davies, not Davis. Hmm... Cardiff
-- home of the "red-rain-is-alien-life" theory. OK, what's the
theory? Well, that Venus formed "by a near head-on collision
of two large planetary embryos, as might be expected from
favoured oligarchic planetary accretion."

    A "head-on" collision means that ONE of the two equal
near-planets would have to have been moving in a retrograde
orbit about the Sun. How can I explain how difficult it is to
explain retrograde motion?

    All the planets revolve prograde. All the planets rotate
prograde except Venus, Uranus, and Pluto. All the good-sized
moons orbit prograde except Triton. There are some retrograde
small or asteroidal moons of the giant planets. Triton we
explain as a retrograde capture from the Kuiper Belt or from
Pluto. All but 20 of the tens of thousands of asteroids orbit
prograde. All but a handful of exoplanets orbiting other stars
are prograde. Comets are a mix because they "choose" an orbit
by just falling in.

    A retrograde giant planetesimal as close to Sun as the Venus
orbit is a billion-to-one shot... at least. I'd believe the Red Rain
first.

    And last, since this paper, ESA has released results from
Venus Express that show that water is still being lost from
the top of atmosphere, an astounding result if you believe
Venus has lost all its water and is bone dry. Venus is still
leaking water, still outgassing. You can forget the totally
dry Venus proposed by this paper. You can also forget the
notion that whatever happened to Venus happened billions
of years ago. If it's still outgassing, the disaster was (geologically)
recent, say, a half billion years ago?

    If you wonder what else besides asteroids that could have
hit Venus, well, it could also be the fall of a retrograde moon.
A prograde moon (like ours) is gradually pushed away by the
momentum transfer of tidal friction, but a retrograde moon
is pulled down to the Roche Limit, where it breaks up and
falls to the planet below. Talk about A Really Bad Day --
the Moon is falling.

    Or, a large asteroid could have been captured in a close
orbit; retrograde capture is much easier than prograde. Then,
the following breakup and fall would melt the crust (if the
moon was big enough). For more, Google "Malcuit Venus."
Dr. Malcuit is a geologist at Denison U. in Ohio and has
been doing computer simulations of this problem for
20 years.

    Venus, Problem Child of the Solar System... If the Earth
had been whacked with a 300-km object a half billion years
ago, the crust would have melted, the oceans would have boiled
off, the carbonates on the surface would devolved in the
superheated steam into CO2, forcing the temperature and
pressure to rise catastrophically and finish the job.

    The Earth has enough carbonates on its surface to form a
CO2 atmosphere of 90 bar pressure. (Interestingly, the Earth-sized
Venus has 90 bar of CO2). The Earth would be 400 degrees.
The Earth would have high plateau continents (like Venus),
vast abysmal plains where the sea beds once were (like
Venus), and rippled and folded "undersea" mountains and
sea-mounts at middle elevations (like the RTT on Venus)

    There, but for grace of asteroid, go I. Oh, well, probably
all a coincidence.


Sterling K. Webb
----------------------------------------------------------------------------
----- Original Message -----
From: "Paul H." <oxytropidoceras at cox.net>
To: <meteorite-list at meteoritecentral.com>
Sent: Sunday, April 25, 2010 9:06 PM
Subject: [meteorite-list] Venus Catastrophic Resurfacing
HypothesisChallenged


> Dear Friends,
>
> Ribbon tessera terrain on Venus challenges catastrophic
> resurfacing hypothesis.
>
> Venus Records a Rich Early History
> ScienceDaily, March 25, 2010)
>
> http://www.sciencedaily.com/releases/2010/03/100326125438.htm
>
> the paper is:
>
> Hansen, V. L., and I. Lopez, 2010, Venus records
> a rich early history. Geology. vol. 38, no. 4,
> pp. 311-314, doi:10.1130/G30587.1
>
> http://geology.gsapubs.org/content/38/4/311.abstract
>
> Hansen, V. L., and I. Lopez, 2009, Implications of
> Venus Evolution Based on Ribbon Tessera Terrain
> Relations Within Five Large Regional Areas. 40th
> Lunar and Planetary Science Conference, (Lunar
> and Planetary Science XL), held March 23-27, 2009
> in The Woodlands, Texas, id.2306
>
> http://www.lpi.usra.edu/meetings/lpsc2009/pdf/2306.pdf
>
> http://adsabs.harvard.edu/abs/2009LPI....40.2306H
>
> A related article:
>
> Did A Mega-Collision Alter Venus?
> ScienceDaily (Feb. 27, 2008)
>
> http://www.sciencedaily.com/releases/2008/02/080226160017.htm
>
> The paper is:
>
> Davis, H. J., 2009, Did a mega-collision dry Venus'
> interior? Earth and Planetary Science Letters.
> vol. 268, no. 3-4, pp. 376-383.
>
> http://dx.doi.org/10.1016/j.epsl.2008.01.031
>
> Yours,
>
> Paul H.
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Received on Mon 26 Apr 2010 02:50:32 AM PDT