PLEASE NOTE:


*

Date sent: Tue, 04 Feb 1997 17:06:24 -0500 (EST)
From: HUMBPEIS B.J.PEISER@livjm.ac.uk
Subject: Re: THE TIMES 4 February 1997
To: cambridge-conference@livjm.ac.uk
Priority: NORMAL


The following article about the latest research findings
by Prof Mark Bailey and his Russian colleague Vacheslav
Emel-Yanenko appeared in today's THE TIMES (London, 4
February 1997) on page 6. Prof Bailey is the Director of
the Armagh Observatory and a member of the Organising
Committee of the 2nd SIS Cambridge Conference.


EARTH AT RISK OF COLLISION WITH UNSEEN COMETS

By Nick Nuttall

Thousands of invisible comets may be hurtling into the
solar system on a potential collision course with Earth,
scientists said yesterday.
But spotting the comets - called "dead" comets
because they are inactive and pitch black - is "like
looking for a black cat in a coal cellar", according to
one expert.
The findings will increase concern among some
scientists that mankind is at risk from a devastating
impact of the kind that caused the extinction of the
dinosaurs. Asteroids had previously been thought to pose
the greatest danger of extraterrestrial devastation:
craters on the Earth's surface bear testimony to
bombardements from space from objects about a kilometre
across.
The new research indicates that the danger from dead
comets which, like Halley's comet, are formed in a place
called the Oort Cloud on the edge of the solar system,
may be as big, if not bigger, than that posed by
asteroids.
Only about 20 comets, such as Halley's, have previously
been detected but new research indicates that between
1,000 and 4,800, up to six miles across, may be heading
this way unseen. Many are likely to have orbits that
bring them through the solar system every 200 years,
which means that 50 a year could be passing by on paths
that may take them near to Earth.
The research, to be released later this month at the
Fermor Memorial Meeting of the Geological Society in
London and at the meeting of the Royal Astronomical
Society in March, has been undertaken by Mark Bailey of
the Armagh Observatory in Northern Ireland and Vacheslav
Emel-Yanenko, an astronomer from Chelyabinsk in the
Russian Federation.
Professor Bailey said yesterday: "We are aware of
around 20 comets like Halley's. For every one we see,
there may be at least 100 times as many in similar
orbit that we do not see.
"This may be a conservative figure. Our calculations
indicate that there may be between 1,000 and 5,000 that
we have yet to see."
The findings are based on studies into the rate at
which comets are entering the solar system from the Oort
Cloud. Professor Bailey said that about one new comet
arrived every year.
Most of these are ejected into interstellar space but
the scientists estimate that about 1 per cent are trapped
into short-period orbits that take them around the Sun
every 200 years.
The researchers believe that they survive for half a
million years, leaving up to 5,000 in orbit.
Professor Bailey said that comets such as Halley's were
visible because they had volatile gases and streams of
jets firing into a tail. Dead comets were inert.
It is also possible that dead comets, technically known
as cometary asteroids, may disintegrate far faster than
the team supposes. This would mean that many may now be
little more than pencil-thin streams of meteoroids which
would be hard to detect but which could cause no harm to
the Earth.
Several astronomers have called on governments to set
up networks of telescopes to give an early warning of
approaching asteroids, large chunks of celestial debris
formed in the asteroid belt between Mars and Jupiter.
The belt is considered to be a graveyard of rubble from
a planet that failed to form, with asteroids ejected from
time to time. Several hundred have been detected.
Professor Bailey said that it may now be necessary to
supplement such a system with infra-red telescopes
covering the whole sky to seek out the dead comets.



*

Date sent: Tue, 04 Feb 1997 13:49:39 -0500 (EST)
From: HUMBPEIS B.J.PEISER@livjm.ac.uk
Subject: Re: Welcome to the CAMBRIDGE-CONFERENCE
To: cambridge-conference@livjm.ac.uk
Priority: NORMAL


*** WELCOME TO THE CAMBRIDGE-CONFERENCE ***

The CAMBRIDGE-CONFERENCE is an e-mail network put
together by B.J.Peiser@livjm.ac.uk in the run-up of the
2nd SIS Cambridge Conference on "Natural Catastrophes
during Bronze Age Civilisations: Archaeological,
Geological, Astronomical and Cutural Perspectives"
[Fitzwilliam College, Cambridge University 11-13 July
1997].

Members of this list include astronomers, archaeologists,
climatologists, historians, geologists, sociologists and
other people from around the world who will participate
or have shown interest in the Cambridge Conference.

It is the aim of the CAMBRIDGE-CONFERENCE network to
disseminate the latest information related to the topics
of the forthcoming conference and to keep you up to date
about related reseach, news and further announcements.

It is also intended that reviews of new publications,
short articles and announcements are exchanged among the
members of this list. As a member you are now able to
send mail and information to colleagues throughout the
world - and you will receive similar information from
them.

Can I ask you to forward relevant messages to friends and
colleagues interested in the multidisciplinary topics of
the Cambridge Conference. Should anyone wish to
subscribe to this list or should you like to
unsubscribe, please contact B.J.Peiser@livjm.ac.uk.

How do I send mail to the CAMBRIDGE-CONFERENCE?

Send your e-mail message to:

Cambridge-Conference@livjm.ac.uk

and your mail will be distributed to everyone on the
list.

Should you wish to contact the administrator of if
you need further information about this list, please do
not hesitate to contact me.

Dr Benny J Peiser
Liverpool John Moores University
School of Human Sciences
B.J.Peiser@livjm.ac.uk



*

Date sent: Tue, 4 Feb 1997 15:45:54 +0100
To: Cambridge-conference@livjm.ac.uk
From: Bas van Geel vangeel@bio.uva.nl
Subject: climate change 2650 BP

Dear colleagues,

It is a good idea to start an E-mail network for those that will attend
/are interested in the topic of/ the Cambridge Conference on Natural
Catastrophes during Bronze Age Civilisations.

I am a paleoecologist specialized in peat studies and I am very interested
in climate change and the possible effects for prehistoric Man. Last week
the following publication appeared:

Van Geel, B., Buurman, J. and Waterbolk, H.T., 1996. Archeological and
paleoecological indications for an abrupt climate change in The Netherlands
and evidence for climatological teleconnections around 2650 BP. Journal of
Quaternary Science 11: 451-460.

When I presented the data and ideas as included in that article during a
meeting in The Netherlands, I got strong opposition by a prominent
archaeologist. My ideas (and evidence) that climate change around 2650 BP
was important for prehistoric farmers living in marginal areas were called
'ecological determinism' and 'old-fashioned'. Apparently the common opinion
(?) among modern archaeologists seemed to be more important than my
evidence. Here follows the abstract of the article. In case you are
interested in the complete publication and you do not have JQS in your
library you could ask me to send a copy. I that case please do not use
'reply' but send the message directly to my E-mail address:
vanGeel@bio.uva.nl

Best wishes,
Bas van Geel

Abstract of the above-mentioned paper in JQS:
A sudden and sharp rise in the 14C-content of the atmosphere, which
occurred between ca 850 and 760 calendar yr BC (ca 2750-2450 BP on the
radiocarbon time scale), was contemporaneous with an abrupt climate change.
In northwest Europe (as indicated by palaeoecological and geological
evidence) climate changed from relatively warm and continental to oceanic.
As a consequence, the groundwater table rose considerably in certain
low-lying areas in The Netherlands. Archaeological and palaeoecological
evidence for the abandonment of such areas in the northern Netherlands is
interpreted as the effect of a rise of the water table and the extension of
fens and bogs. Contraction of population and finally migration from these
low-lying areas which had become marginal for occupation, and the earliest
colonization by farming communities of the newly emerged salt marshes in
the northern Netherlands around 2550 BP, is interpreted as the consequence
of loss of cultivated land. Thermic contraction of ocean water and/or
decreased velocity and pressure on the coast by the Gulf Stream may have
caused a fall in relative sea-level rise and the emergence of these salt
marshes. Evidence for a synchronous climatic change elsewhere in Europe and
on other continents around 2650 BP is presented. Temporary aridity in
tropical regions and a reduced transport of warmth to the temperate climate
regions by atmospheric and/or oceanic circulation systems could explain the
observed changes. As yet there is no clear explanation for this climate
change and the contemporaneous increase of 14C in the atmosphere. The
strategy of 14C wiggle-match dating can play an important role in the
precise dating of organic deposits, and can be used to establish possible
relationships between changing 14C-production in the atmosphere, climate
change, and the impact of such changes on hydrology, vegetation, and human
communities.

Keywords: Climate change, archaeology, palaeoecology, teleconnections, 2650 BP.


+--------------------------+-------------------------------------+
| Dr Bas van Geel | Internet E-mail :vanGeel@bio.uva.nl |
| University of Amsterdam | Phone secr. :+31-20 525 7844 |
| Faculty of Biology | Direct phone :+31-20 525 7664 |
| Kruislaan 318 | Fax :+31-20 525 7662 |
| NL - 1098 SM Amsterdam | |
| The Netherlands | |
+--------------------------+-------------------------------------+

 



CCCMENU CCC for 1997

The content and opinions expressed on this Web page do not necessarily reflect the views of nor are they endorsed by the University of

The content and opinions expressed on this Web page do not necessarily reflect the views of nor are they endorsed by the University of Georgia or the University System of Georgia.