[meteorite-list] A Metallic Asteroid May Have Coincided With The Fall Of Rome

From: mark ferguson <refam_at_meteoritecentral.com>
Date: Thu Apr 22 10:18:26 2004
Message-ID: <20030209051243.42321.qmail_at_web40209.mail.yahoo.com>

Hi Ron and List
Seems many things happened in the 5th century AD. A
meteorite impact sure would upset the masses, but
findings from around the world show a significant
volcanic event occurred about 436-437 AD. Writings
from many places indicate severely diminished sunlight
hrs for many months and lending credibility to the
term "The Dark Ages". It appears that a super plinian
volcano, very possibly Krakatoa, let loose and effects
may well have been felt world wide. Sulphuric spikes
in ice corings correlate the date as well as tree
rings from lock and bog fortresses in Ireland. A
Chinese prince writes of yellow dust falling to the
ground so thick you can scoop up handfuls and with the
sun shinning only dimly for an hour or two a day, he
fears how to feed his people as the crops won't grow
in conditions like this. A plague runs rampant though
the "civilized world" of the Roman Empire and Europe
since the sun shipitifullyully for a couple hours a
day and cold temperatures have set in when it should
be warm. Famine hits hard in South America and disease
speads in the Moche Empire. This, I believe is what
happened to the Roman Empire and the Moche of Peru. I
also believe it caused the dark ages, and it isn't
just a term used to describe a time of no advancement
and loss of intelligence in a civilization.
Mark


--- Ron Baalke <baalke_at_zagami.jpl.nasa.gov> wrote:
>
>
>
http://www.guardian.co.uk/online/science/story/0,12450,889308,00.html
>
> A metallic asteroid may have coincided with the fall
> of Rome, says Duncan Steel
>
> The Guardian (United Kingdom)
> February 6, 2003
>
> In the early fifth century, rampaging Goths swept
> through Italy.
> Inviolate for 1,100 years, Rome was sacked by the
> hordes in 410 AD.
> St Augustine's apologia, the City of God, set the
> tone for Christians
> for the next 16 centuries.
>
> But the Rome of that era came close to suffering a
> far worse calamity.
> A small metallic asteroid descended from the sky,
> making a hypervelocity
> impact in an Apennine valley just 60 miles east of
> the city. This
> bus-sized lump of cosmic detritus vaporised as it
> hit the ground. In
> doing so, it released energy equivalent to around
> 200 kilotonnes of TNT:
> around 15 times the power of the atomic bomb that
> levelled Hiroshima in
> 1945.
>
> Pescara is on the Adriatic coast, located across the
> Italian peninsula
> from Rome. Housed there is the International
> Research School of Planetary
> Sciences, where staff and students study topics
> ranging from planetary
> geology to astrobiology. In 1999, a young impact
> cratering specialist
> from Sweden, Jens Ormö, arrived to take up a
> three-year position
> funded by the European Union.
>
> Ormö, it happens, is keen on hill walking, and just
> inland from Pescara
> are some of the most spectacular mountains in the
> Apennines. He decided
> that some hiking in the area of the Sirente Massif
> was in order, and so
> he consulted a local guidebook. As he thumbed its
> pages, Ormö came
> across a photograph of something that amazed him.
> What he saw, labelled
> as a natural lake, was surely an impact crater.
>
> An expedition to the site of the putative impact, on
> the Sirente plain,
> was hastily organised. Colleagues confirmed Ormö's
> initial suspicion.
> Here was an impact crater about 140 metres wide,
> previously unrecognised
> despite lying only a short distance from a busy
> road, and visible from
> miles away. It has appeared on maps for centuries,
> and in guidebooks
> for decades - but no one had recognised its
> significance.
>
> Natural lakes are common in the area. But this one
> has a raised rim, now
> about two metres high, but originally rather
> thicker. This was produced
> by the asteroid throwing material out from the
> impact zone, as it crashed
> at a speed of around 20km per second, producing a
> huge explosion. Later
> filled with rainwater, the crater is now only a few
> metres deep, and
> occasionally dries up during hot summers. But it was
> more than 30 metres
> to the bottom when first formed. Centuries of
> weathering has eroded its
> bank and gradually filled it in.
>
> Relatively modest craters like this are unusual,
> because small asteroids
> can only reach the ground intact if they are
> metallic, and thus strong
> enough to withstand the physical shock of slamming
> into the atmosphere
> at such speeds. The best guess at present is that
> the asteroid was about
> 10 metres across, and had a composition similar to
> nickel-iron meteorites.
> If it had been stony in composition, as most
> asteroids are, it would have
> shattered in flight and released all of its energy
> in a phenomenal
> explosion. This is what happened when a 50-metre
> rock blew up over
> Siberia in 1908, leaving no crater.The expectation
> of a metallic impactor
> is backed up by the identification of rust grains in
> the surrounding soil.
>
> Confirmation of the impact origin comes from 17
> smaller craters,
> typically 10 metres wide, scattered around the
> Sirente plain. These are
> due to fragments of the asteroid that separated in
> flight through the
> atmosphere. A magnetic survey shows that most are
> associated with
> anomalously high fields, indicating sub-surface
> metallic lumps.
>
> Crater fields like this are not unusual. In central
> Australia, 120km
> south of Alice Springs, the Henbury craters were
> formed in a similar way.
> What is peculiar about the Sirente crater is where
> it occurred, and its
> youth. Dozens of ancient craters are known in
> northern Europe,
> geological stability allowing their long-term
> preservation. Two examples
> are the Ries and Steinheim basins in Germany. Many
> others are known in
> Scandinavia. But these are all huge, and millions of
> years old. There
> is a small, recently formed crater in Estonia, but
> the Sirente crater
> is of far greater interest: it was excavated around
> the time of the
> fall of the Roman Empire, and close to Rome itself.
>
> The crater has been dated through radiocarbon
> analysis of a drill core
> cut down through the bank. The uppermost material,
> having been thrown
> out of the cavity, contains organic matter older
> than the impact. At
> the original ground level the radiocarbon ages
> minimise, and then deeper
> down the material is older again.
>
> The data indicate that the crater was formed in
> about 412 AD, with an
> uncertainty of 40 years in either direction.
> Additional sampling may
> allow this spread to be reduced, but it is clear
> that the event
> occurred close to the fall of Rome: some time
> between 370 AD and 450
> AD, when the city was again under attack, this time
> by the Vandals.
>
> No matter what the trajectory of the asteroid entry,
> it would have
> been a phenomenal sight from Rome, and scarier still
> for those closer
> to ground zero. The fireball produced would have
> only lasted 10 seconds
> or so, but would have been brighter than the sun,
> and so visible
> even in daytime. The smoke trail left in the
> atmosphere would have
> been visible for some hours.
>
> Another remarkable aspect of the event is that the
> main crater sits
> squarely in the middle of the Sirente plain, which
> is only about a
> mile long, and half that wide, being surrounded by
> mountainous
> terrain. It could be that this is just luck.
> Alternatively, the
> array of craters now identified might represent only
> a tiny
> fraction of the havoc wreaked, with many other
> impacts on the
> mountainsides having long since eroded or been
> hidden by tree growth.
>
> Even considering simply the energy involved in
> forming the known
> crater, it is sobering to ponder what might have
> happened should
> the impact zone have been on the flat coastal plains
> nearer Rome,
> rather than in the mountains. Scaling from nuclear
> bomb tests
> indicates that a 200 kilotonne surface explosion
> would devastate an
> area of 100 square
> kilometres.
>
> A frequently used aphorism says that Rome was not
> built in a day.
> That's true. But it did come awfully close to being
> destroyed
=== message truncated ===


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Received on Sun 09 Feb 2003 12:12:43 AM PST