PLEASE NOTE:
*
CCNet 71/2001 - 23 May 2001
----------------------------
Four Thousand Years Ago
Kings and chieftains ruled, while ordinary humans
planted their crops, raised children, paid taxes.
Empires grew in Mexico, China, India, and Egypt,
sun and rain blessed fertile land, while food and water
were enough for all, and populations slowly grew.
One day it ended with a growing dark, wind, dust,
the sun obscured; perhaps the ground shivered.
Then the next day, and the next were cold and dark,
and weeks and months were dull and grey.
Leaves turned pale or fell, grain stalks short and spindly,
bees vanished along with flowers, ants, butterflies.
Crops failed, starvation loomed, taxes were not paid,
raiders came to loot for grain, rulers trembled
and then the empires and kingdoms fell. Somewhere
on this huge Earth a small invader, no bigger than a hill,
had used its gigatons of energy to send a monstrous cloud
of dust and smoke and fractured rock so high
the Sun was blotted out for months, the Earth bled,
and human history's brief span faltered for a moment.
Malcolm Miller
stellar2@cyberone.com.au
9.9.99
"An Islamic leader was taken to prison Tuesday where he will
serve a
two-year sentence for claiming that an earthquake was God's
revenge
against Turkey for its secularist policies. Mehmet Kutlular,
leader of
the Nur Cemaati sect, was convicted of inciting religious hatred
for
a booklet distributed by his group in October 1999. The booklet
said the
quake that struck Turkey's northwest in August that year, killing
more
than 17,000 people, was divine retribution for laws that ban
Islamic-style
head scarves in schools and public buildings."
--The Associated Press, 22 May 2001
"Astronomers at the most famous observatory in France are up
in arms
over plans to build a fast-food restaurant nearby. The Times
reports the
astronomers are concerned the fat fumes produced by french fries
and
hamburgers could create a haze, giving the universe an unusual
appearance.
The observatory was used to draw up a detailed lunar map for
NASA's Apollo
mission. Critics argue that had the fast-food chain been around
in 1969,
Neil Armstrong might have mistaken the moon for a fat droplet,
the paper
reports."
--ABC News, 23 May 2001
(1) ENVIRONMENTAL CATASTOPHES AND RECOVERY IN THE HOLOCENE
Brunel University, March 2001
(2) GALILEO GETS ONE LAST CLOSE ENCOUNTER WITH JUPITER'S CALLISTO
NASANews@hq.nasa.gov
(3) DUST BEGETS DUST
Science@NASA,
22 May 2001
(4) BLAMING GOD FOR EARTHQUAKE DEATHS LANDS ISLAMIC
FUNDAMENTALIST IN JAIL
ABC News, 22 May 2001
(5) FOSSIL FINDINGS MAY FORCE REVISIONS IN THE HISTORY OF LIFE
The New York Times, 22 May 2001
(6) COMET CATASTROPHE: LIMITS TO SPECULATION
Brian G. Marsden <brian@cfaps5.harvard.edu>
(7) HALE-BOPP IN 2213BC ...
Duncan Steel <D.I.Steel@salford.ac.uk>
(8) DID HALE-BOPP CAUSE THE SAHARA?
Andy Nimmo <andy-nimmo@ntlworld.com>
(9) BACKGROUND: COMETS AND DISASTER IN THE BRONZE AGE
BRITISH ARCHAEOLOGY, December 1997, No 30, pp.
6-7
(10) BACKGROUND II: BEYOND THE YOUNGER DRYAS: COLLAPSE AS
ADAPTATION TO
ABRUPT CLIMATE CHANGE
Harvey Weiss, Professor of Near Eastern
Archaeology, Yale University
(11) AND FINALLY A RATHER FRUITLESS QUESTION: BEFORE THE BIG
BANG, THERE WAS
... WHAT?
The New York Times, 22 May 2001
==========
(1) ENVIRONMENTAL CATASTOPHES AND RECOVERY IN THE HOLOCENE
From Brunel University, March 2001
http://www.brunel.ac.uk/depts/geo/Catastrophes/menu.html
The conference will be convened in early September, 2002. The
venue for the
meeting will be Brunel University.
The conference will consider both natural and anthropogenic
events.
Importantly, the conference will examine how quickly ecosystems
and
civilisations are able to recover from catastrophic events. With
the growing
recognition that major natural and anthropogenic events can have
abrupt
global impacts, this meeting would be a timely opportunity to
assess the
sensitivity of modern society to extreme natural and
anthropogenic threats.
The meeting will combine an oral programme of major keynote
addresses with
an accompanying poster session. Poster papers will be invited
from any
interested participating scientist and the session will be an
opportunity
for Brunel researchers to present the results of recent research
in this
field.
Plenary Sessions
Environmental Causes of Civilisation Collapse
Collapse of the late Bronze age (3rd millenium) civilisation
Collapse of the Mayan and Anasazi civilisations
Climate impacts on Easter Island: natural or anthropogenic cause?
Earthquake destruction at Sodom and Gomorra: earthquake storms in
the Holy
Land
Societal responses to earthquakes: insights from the
Mediterranean
archaeological record
Postglacial flooding of the Persian Gulf and settlement
abandonment
Causes and Mechanisms of Geological Catastrophes
Geo-catastrophism
Supervolcano eruptions
Extraterrestrial impacts and cometary near-misses
Mega floods
The 8200 year BP event
Catastrophic marine flooding in the Black Sea
Gas hydrates slumps in the Arctic and Norwegian Sea
Societal impact of tsunamis in the Pacific
Climatic Catastrophes: Impact and Recovery
Nuclear winters
The drying up and recovery of Lake Victoria: ecological
implications
Volcanic dry fogs and pandemics
Ecological impact and recovery from fires and hurricanes
Biological Catastrophes: Impact and Recovery
Plant recovery after Mount St Helens
Human impact on small Pacific islands
Malaria in East Africa and El Nino
Haemorrhagic fever in central Amercia
Closing Debate
Global warming: prediction and future recovery
Loss of biodiversity
Organisational committee
Conference leaders: Professor Suzanne Leroy <suzanne.leroy@brunel.ac.uk>
and Dr. Iain Stewart <iain.stewart@brunel.ac.uk>
Field trip organiser: Professor Callum Firth
Conference treasurer: Dr Steve Kershaw
Department of Geography and Earth Sciences,
Brunel University,
Uxbridge,
London,
UB8 3PH, U.K.
Tel: +44 (0) 1895 203215
Fax: +44 (0) 1895 203217
Scientific advisory committee
Professor S. Leroy for the INQUA Holocene Commission
Dr I. Stewart for the INQUA Neotectonic Commission
Professor C. Firth for the INQUA Coastal and Sea Level Commission
Dr. C. Turney for the INQUA Tephrachronology and Volcanology
Commission
Professor B. Eriksen for the INQUA Human Evolution and
Palaeoecology
Commission
Professor V. Baker for the INQUA Global Continental
Paleohydrology
Commission
===========
(2) GALILEO GETS ONE LAST CLOSE ENCOUNTER WITH JUPITER'S CALLISTO
From NASANews@hq.nasa.gov
Donald Savage
Headquarters, Washington,
DC
May 22, 2001
(Phone: 202/358-1547)
Guy Webster
Jet Propulsion Laboratory, Pasadena, CA
(Phone: 818/354-6278)
RELEASE: 01-97
GALILEO GETS ONE LAST CLOSE ENCOUNTER WITH JUPITER'S CALLISTO
On a third and final tour of duty in the Jovian system, NASA's
dauntless
Galileo spacecraft makes its closest pass yet to Jupiter's
outermost large
moon.
Friday, May 25, the orbiter should skim over Callisto, at an
altitude of
about 123 kilometers, or 76 miles, at 7:24 a.m. EDT. If Callisto
were the
size of a baseball, that would be
just a nickel's thickness away.
Mission managers expect the pull of the moon's gravity to alter
Galileo's
orbit around Jupiter. "The main reason we're flying so close
to Callisto is
to set up flybys of Io," said Dr. Eilene Theilig, Galileo
project manager at
NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA. Io is an
intensely
volcanic moon closer to Jupiter that continually resurfaces
itself with
fiery eruptions.
Galileo will pass over polar regions of Io in August and October
to help
scientists determine if the seething and violent moon generates
its own
magnetic field. "Since we have to go close to Callisto
anyway to get to Io,
we'll take advantage of the opportunity for studying
Callisto," said JPL's
Dr. Torrence Johnson, Galileo project scientist.
Unlike the planet's other large moons, Callisto, which is about
as big as
the planet Mercury, appears to be inactive and still bears
craters billions
of years old.
Although earlier magnetic studies by Galileo indicated that
Callisto may
have a liquid saltwater layer deep beneath its surface, Callisto
hasn't
drawn the excitement generated by Io or its sister moon Europa,
which
appears to have liquid water closer to its surface, or two-toned
Ganymede.
"Callisto is sort of the ugly duckling of the moons, but
it's the one we
need to look at to get the bombardment history of the Jovian
system,"
Johnson added. "The craters on Callisto are the visible
record of what sizes
of comets and other objects have pelted Jupiter and its moons
with what
frequency over the past four billion years."
Data from the flyby will be transmitted to Earth over the next
two months.
Scheduled observations include high-resolution imaging to study
the density
of small craters and the details of how some features appear to
be degraded
or eroded, said Dr. Duane Bindschadler, leader of Galileo's
science planning
team. "Some earlier imaging of Callisto has shown fewer
small craters than
expected."
Scientists also plan to snap new pictures of Io, though from a
much greater
distance than Callisto, and hope to see if a volcanic plume
detected near
Io's North Pole five months ago is still active. On Aug. 5,
Galileo will
pass directly over the plume's source area at an altitude of less
than 350
kilometers, or about 220 miles.
Another set of planned observations this week will point at
Jupiter. Galileo
will make a map of Jupiter's clouds in infrared wavelengths.
"One goal is to
see if fresh clouds are still being made at the same types of
locations they
were during similar mapping more than five years ago," said
Dr. Kevin
Baines, JPL atmospheric scientist. Another is to check for
"brown barges," a
type of dark cloud that was prominent on Jupiter when NASA's two
Voyager
spacecraft flew by in 1979,
but has not been seen during the years since Galileo began
orbiting Jupiter
in 1995. Baines believes recent observations from Earth-based
telescopes
hint at a return of brown barges.
Galileo's mission was originally scheduled to end in 1997, but
has been
extended repeatedly as the spacecraft continues to return
scientific
discoveries. The orbiter has survived more
than three times the cumulative radiation exposure it was
designed to
withstand. Some electronic components have been affected by the
radiation,
and each swing near Jupiter increases the odds of more serious
damage from
exposure to the radiation belts around the planet.
Galileo has made 30 previous flybys of Jupiter's large moons,
including
seven of Callisto. Before reaching Jupiter, it made close passes
of Venus,
Earth and two asteroids. After three more encounters with Io and
one with
the small inner moon Amalthea, Galileo's mission will end in 2003
with a
final plunge into the crushing pressure of Jupiter's atmosphere.
JPL, a division of the California Institute of Technology in
Pasadena,
manages Galileo for NASA's Office of Space Science, Washington,
DC.
Additional information about the Galileo, Jupiter and Jupiter's
moons is
available online at:
http://galileo.jpl.nasa.gov
==========
(3) DUST BEGETS DUST
From Science@NASA, 22 May 2001
http://science.nasa.gov/headlines/y2001/ast22may_1.htm?list68077
Everyone knows that dry weather leads to dusty soils, but new
research
suggests that dust might in turn lead to dry weather.
May 22, 2001 -- Windblown desert dust can choke rain clouds,
cutting badly
needed rainfall. This new discovery made with the help of NASA
satellites
suggests that droughts over arid regions, such as central Africa,
are made
even worse by land management practices that expose new dust and
accelerate
the growth of deserts.
In other words: Dust begets dust!
These findings, reported in the Proceedings of the National
Academy of
Sciences, present a new view of the decades-long drought in the
African
Sahel, a semi-arid region of Africa adjacent to the Sahara
Desert. The
grassy savannas of the Sahel once provided natural pasture land
for
livestock, but increasing demands on the land due to population
growth have
lead to desertification, which has been accompanied by increasing
levels of
airborne dust during the rainy season.
More airborne dust is not necessarily a result of decreased
rainfall but
rather its cause, according to scientists from Israel's Hebrew
University
and the Weizmann Institute. "This impact of desert dust on
rainfall was not
known before," says lead author Daniel Rosenfeld, Hebrew
University,
Jerusalem. Furthermore, it was the opposite of what scientists
expected.
Before Rosenfeld et al.'s research, many scientists thought that
large
airborne dust particles would speed the formation of rain by
forming giant
cloud condensation nuclei and larger cloud droplets.
Not so.
"Our laboratory analysis of the desert dust showed that
[dust] particles
contained very little water-absorbing matter," says
co-author Yinon Rudich
of the Weizmann Institute. "As a result, even large dust
particles form
relatively small cloud droplets."
The research shows dust actually amplifies the process of
creating deserts.
Activities that expose and disrupt topsoil, such as grazing and
agricultural
cultivation, can increase the amount of dust blown into the air.
More dust
reaching rain clouds produces less rainfall, which exacerbates
the drought
conditions and contributes to the desertification of the
landscape. In
desert regions, dust storms can often kick up clouds of dust that
blanket
thousands of square miles of land, dramatically illustrated by
the
record-setting dust cloud that blew from Asia to North America
last month.
Dust and other types of aerosol particles blowing into clouds act
as nuclei
where water vapor can condense to form cloud droplets. If a lot
of dust
enters a cloud, the available water is spread over many small
droplets.
These small droplets grow more slowly through collisions with one
another to
the size of a raindrop, and the cloud yields less rainfall over
the course
of its lifetime.
What the researchers saw in two separate cases, using different
satellite
observations, was that cloud droplets were smaller as dust
concentrations
increased.
NASA's Tropical Rainfall Measuring Mission (TRMM) spacecraft
captured images
of clouds over the Atlantic Ocean off the coast of northern
Africa during a
major March 2000 dust storm. Droplet sizes steadily increased the
farther
the clouds were from dust-filled air. Rain was falling only from
the
dust-free clouds even though all the clouds contained equal
amounts of
water.
The researchers also observed similar behavior in clouds over the
eastern
Mediterranean Sea in March 1998, using data from aircraft and a
U.S. weather
satellite.
Rosenfeld has used TRMM observations in two other recent studies
to show
that aerosols from biomass-burning smoke and urban air pollution
also reduce
rainfall. Combined with the negative impact of desert dust,
Rosenfeld
believes the aerosol rainfall-suppression effect can have a major
impact on
regional and global climate.
"The recent observations of the impact on precipitation of
all kinds of
aerosols, each with a major human contribution, show a major
climate change
issue that has nothing to do with greenhouse gases," says
Rosenfeld. "Still,
this is perhaps the climate-change effect with the greatest
socio-economic
impact on water-scarce areas."
==========
(4) BLAMING GOD FOR EARTHQUAKE DEATHS LANDS ISLAMIC
FUNDAMENTALIST IN JAIL
From ABC News, 22 May 2001
http://abcnews.go.com/wire/World/ap20010522_797.html
Turkish religious leader imprisoned for saying quake was God's
revenge
The Associated Press
ISTANBUL, Turkey (AP) An Islamic leader was taken to prison
Tuesday where he
will serve a two-year sentence for claiming that an earthquake
was God's
revenge against Turkey for its secularist policies. Mehmet
Kutlular, leader
of the Nur Cemaati sect, was convicted of inciting religious
hatred for a
booklet distributed by his group in October 1999.
The booklet said the quake that struck Turkey's northwest in
August that
year, killing more than 17,000 people, was divine retribution for
laws that
ban Islamic-style head scarves in schools and public buildings.
A court last year sentenced Kutlular to two years in prison, but
allowed him
to remain free pending an appeal that was rejected by a court
earlier this
year.
On Tuesday, an administrative court ordered police to take him to
Istanbul's
Metris prison to begin serving his two-year sentence. He will be
held for a
minimum of nine months and 23 days.
Secularism is rigorously enforced in Turkey, an overwhelmingly
Muslim state.
Copyright 2001 The Associated Press.
==========
(5) FOSSIL FINDINGS MAY FORCE REVISIONS IN THE HISTORY OF LIFE
From The New York Times, 22 May 2001
http://www.nytimes.com/2001/05/22/science/22SPEC.html
By CAROL KAESUK YOON
After the most devastating mass extinction swept the planet 250
million
years ago, the earth witnessed a nearly unabated increase in the
variety of
living organisms leading to unparalleled heights of diversity -
or so
paleontologists have long thought.
Now a new study in The Proceedings of the National Academy of
Sciences
suggests a radically different picture that, if correct, will
require a
large-scale rewriting of the history of life.
In the first results from a huge new database of fossil records
being
assembled on the World Wide Web by an international team of
scientists,
researchers report findings that suggest there may have been no
such
relentless increase in diversity. In fact, the new results
suggest the
possibility that diversity levels quickly hit a plateau and
stayed put and
that the real peak of life's diversity may have come and gone
more than 400
million years ago.
But scientists, including the authors, cautioned that the results
should be
viewed as preliminary. Even though the new study addresses what
some feel
are critical flaws in the previous work showing steep increases
in
diversity, scientists note the results are a first look at a
complex new
database.
The current study focuses on fossil marine organisms, but
scientists plan to
include records of fossils of all kinds from the span of the
history of life
on earth in the database (flatpebble.nceas.ucsb.edu/public) at
the National
Center for Ecological Analysis and Synthesis, which supported
much of the
work.
But while adopting a wait-and-see attitude, scientists outside
the study
acknowledged that if true, the findings would require a radical
rethinking
of not only when diversity levels rose and fell, but why.
"This calls into question longstanding views of the
diversity of life," said
Dr. Douglas Erwin, a paleobiologist at the Smithsonian
Institution, adding
it was too soon to draw firm conclusions. But he said, "It's
very exciting
for paleontology."
For example, the many theoretical explanations for the steady
increase in
diversity would become irrelevant and a whole new series of
questions about
the relative constancy in levels of diversity would emerge.
"This is a very important enterprise," said Dr. Jeremy
Jackson,
paleobiologist at Scripps Institution of Oceanography, though he
was highly
skeptical of the new work. "If it were true, the implication
would be that
there was some sort of ceiling on diversity, something limiting
it, which
would be fascinating."
It was the pioneering work of Dr. J. John Sepkoski, a
paleobiologist at the
University of Chicago, who died in 1999, that provided the first
evidence
that diversity had been on a steady climb (with occasional minor
setbacks
like the extinction that took the dinosaurs) ever since the
mother of all
extinctions, known as the Permo- Triassic. Similar studies of
plants,
insects and other animals followed and showed the same unending
rise in the
variety of forms of life.
But there have always been nagging doubts. As it turns out,
counting up what
different kinds of fossil organisms lived in any particular time
period is
not as simple as it may sound. Because researchers draw on the
many
published studies of fossils done over the years to fill their
databases,
among the thorny problems is the fact that scientists have
studied some
areas with much greater intensity than others.
In one example of true paleontological zeal, Dr. G. Arthur
Cooper, a
paleobiologist at the Smithsonian Institution, led a 40-year
effort
collecting more than 100,000 fossil specimens from the Glass and
Guadalupe
Mountains in West Texas. The fossils, which are naturally made of
glass,
include the clamlike marine organisms known as brachiopods.
Dr. Cooper, who died recently, "wanted to find every last
species of
brachiopod," Dr. Erwin said.
Yet information from such exhaustive surveys from one time and
place would
be compared with information from much more superficial surveys,
which would
have missed most of the rarer species, from other time periods
around the
world.
Even more problematic is the fact that newer rocks and fossils
are easier to
get at and have been much more intensively studied by
paleontologists. So as
scientists tally the organisms discovered in more than a century
of
paleontological research, they will necessarily find a much
greater
diversity of newer organisms than older ones, whether they were
actually
more abundant in reality or not.
But even with consideration of the acknowledged problems,
scientists said
the consensus remained that the increase in diversity was real.
Dr. John Alroy, paleobiologist at the National Center for
Ecological
Analysis and Synthesis at the University of California at Santa
Barbara, and
Dr. Charles Marshall, paleobiologist at Harvard, are the first
two authors
on the 25-author paper in which researchers tried to get around
some of the
problems by making a variety of statistical attempts to sample
fossil
species equally from the different periods of time. The paper is
dedicated
to Dr. Sepkoski, who is also an author on the study.
The result is a variety of possible chains of events for how
diversity waxed
and waned, all different from the standard view, but all
indicating that the
steep increase in diversity seen in previous studies may have
been
influenced by the bias in information about newer fossils.
Scientists note also that the new study has its own biases. For
example, the
study focuses on marine organisms from around North America and
Europe, and
a different pattern could emerge as the database gains more
geographic
breadth.
"The data's got a lot of dimensions, and there are a whole
range of things
to be done," said Dr. Marshall, who said confidence versus
wariness over the
new results varied greatly even among the 25 authors. He added,
"We ain't
there yet."
And even as paleontologists applauded the Herculean efforts to
work on this
bigger, better database, some suggest the approach itself may be
flawed.
Some including Dr. Jackson say researchers may be better served
by getting
out of the library and into the field, doing new fossil surveys.
Rather than
fighting biases in data collected 100 years ago for other
purposes, they
could collect the most appropriate data in a uniform and
comparable way.
Likely to continue to spur as much criticism as support, the
analyses of the
new database go on.
"I hope they're right," Dr. Erwin said of the new
findings, "because life
will be more interesting for the next 10 or 20 years if they are.
We'll have
to re-examine a lot of assumptions."
Copyright 2001 The New York Times Company
============================
* LETTERS TO THE MODERATOR *
============================
(6) COMET CATASTROPHE: LIMITS TO SPECULATION
From Brian G. Marsden <brian@cfaps5.harvard.edu>
Dear Benny,
While Tom Slattery's remarks about dire events in Mesopotamia in
the year
2213 B.C. (= -2212) are intriguing, to tie those events to a
collision with
"some large part of comet Hale-Bopp", or perhaps,
somewhat more logically,
with "part of a once larger comet" of which Hale-Bopp
was another part, is
carrying speculation too far.
One feature of Hale-Bopp is that its orbit does pass moderately
close to
that of the earth (well, to within about 15 million km). Even
more striking
(and the pun is intended) is the fact that its orbit essentially
intersects
the orbit of Jupiter. The current disposition of the comet's
orbit is that
the comet is closest to the earth's orbit a year or so _after_ it
is at the
intersection point with Jupiter's orbit. Furthermore, given that
the comet's
orbit plane is almost perpendicular to the orbital planes of the
planets,
the likelihood that comet Hale-Bopp would encounter any
significant
perturbers other than Jupiter (and the earth) is extremely small
indeed.
Since, on a given pass, any Jupiter encounter would precede
perihelion, and
since we know the Hale-Bopp orbit in the years before it crossed
Jupiter's
orbit in 1996, it is quite clear that the comet could not have
passed within
15 million km of the earth when it was last here in the 23rd
century B.C.
The actual date of that earlier visit is uncertain by a few
years, but it is
possible that it occurred in 2213 B.C. If so, the comet would
have been near
Jupiter's orbit a year earlier. Certainly, a close encounter with
Jupiter
itself provides a good mechanism for breaking a comet into two or
more
components, but a 2213 B.C. date does not permit such an
encounter. Comets
can also break up without a Jupiter approach, but if a separate
fragment of
the Hale-Bopp progenitor were going to pass by in 2213 B.C., it,
too, would
not have been able to pass within 15 million km of the earth. If
the comet
were to pass close enough to Jupiter to ensure tidal break-up,
that would
have had to have occurred around June 7, 2216 B.C. But Hale-Bopp
would then
have to have been at perihelion around July 7, 2215 B.C., at
which time, as
at the April 1, 1997, perihelion, it would have been far from the
earth, on
the other side of the sun. And much the same would have to
be true for any
companion split off at or after the Jupiter approach.
Separation somewhat
before the Jupiter approach would also be much the same--and in
any case
limited by the 15-million-km minimum.
The only way to have a Hale-Bopp-related earth impact in 2213
B.C. would be
to have had a _much_ earlier break-up, with the piece that was
_not_
Hale-Bopp having its orbit perturbed by Jupiter on an _earlier_
passage in
such a way that its orbit actually intersected that of the
earth. The
chance of that, and then that this piece was even in the vicinity
of the
earth's orbit during the few years around 2213 B.C., then becomes
so remote
that, if we want to postulate a comet impact that year, we should
do better
with a totally unrelated comet...
I speculated on the likelihood of the June 7, 2216 B.C.,
encounter of
Hale-Bopp with Jupiter at the end of a paper I presented at the
"First
International Conference on Comet Hale-Bopp" in 1998.
While this hypothesis
was not--shall we say?--broadly embraced by my fellow
participants, I
maintain that it does come within the limits of _reasonable_
speculation.
But the Slattery speculation does not.
Regards
Brian
=============
(7) HALE-BOPP IN 2213BC ...
From Duncan Steel <D.I.Steel@salford.ac.uk>
Dear Benny,
I enjoyed the essay about possible upheavals in civilization(s)
around the
time that comet Hale-Bopp passed through the inner solar system
around 2213
BC. However, there are real dynamical problems with what is
suggested, or
maybe I should say the question(s) asked. In particular:
>Did our ancient ancestors get bopped by a fragment of
Hale-Bopp?
The answer is: possibly at some time, but there is no reason to
suspect
2213 BC (which is the basis of the argument put forward: direct
physical
influence of comet Hale-Bopp on the Earth in that epoch).
The orbit of that comet, although it is Earth-crossing (i.e.
perihelion
distance less that 1 AU), does not come close to the orbit of our
planet. In
order for a fragment of that comet to have suffered sufficient
differential
perturbations such that it had/has been brought into a condition
producing a
node at 1 AU a very substantial time scale is required. I have
not done any
numerical modelling for this specific comet, but I would guess
that the sort
of interval needed is of order
10^4-10^5 years or more. The time of any such terrestrial impact
as that
suggested by Tom Slattery would therefore be totally disconnected
from any
apparition of the comet itself. I can see no way in which a
fragment of the
comet could be hived off the comet during that apparition and
brought into a
prompt Earth-intersect condition. Comets do break apart - vide
the recent
comets LINEAR - but their fragments follow broadly parallel
paths, and their
distinct orbital evolution is fairly straightforward to follow.
Annual meteor showers show what is required, without recourse to
complex
computer programs representing the celestial mechanics. Comet
Tempel-Tuttle
has an orbit with a node very near 1 AU, and in consequence its
annual
shower (the Leonids) shows cyclic enhancements (of period 33
years) due to
meteoroids released recently (a few rbits ago), but not even in
this case
from the immediate perihelion passage. That is, even in this
example (node
near 1 AU, small meteoroids hence large relative velocities) one
does not
get prompt terrestrial intersections. The situation for comet
Hale-Bopp is
actually more extreme than that of comet Halley. The latter comet
produces
two annual meteor showers, but their activity does not vary much
from year
to year, and the particles involved are 'old' in that they were
released
from the comet many millennia ago. It takes them a long time to
evolve
separately from comet Halley such that they are brought to a node
at 1 AU,
their parent comet having its nodes at present far from that
heliocentric
distance.
In my discussion about the pyramids I forgot to mention that
there is a
well-known reason for the ancient Egyptians being interested in
the pre-dawn
sky (when the zodiacal light may be seen). This is their concern
with the
heliacal rising of Sirius, occurring near midsummer after it had
been hidden
in the solar glare for some weeks. The year counted in that way
by the
Egyptians, the Sothic year, gets its name from the Greek word for
Sirius,
Sothis, which means "scorcher". This is because its
re-appearance heralded
the hottest weather. (Similarly in modern times we may refer to
that time of
year as being the "dog days", Sirius being the Dog
Star, in Canis Major).
The Egyptians eagerly watched the eastern sky at this time of
year for
Sirius to appear, for it was linked not only to the hot weather
but also the
flooding of the Nile.
Kind regards,
Duncan Steel
=============
(8) DID HALE BOPP CAUSE THE SAHARA?
From Andy Nimmo <andy-nimmo@ntlworld.com>
Re: (1) COMET CATASTOPHE: A SPECULATIVE FEATURE BY TOM SLATTERY
From Robert Clements
<Robert.Clements@dva.gov.au>
Dear Dr Peiser,
I found this piece very interesting but cannot understand the
repeated
references to a 'temporary' climate change. Surely this was when
the Sahara
desert appeared? The climate change was permanent and is still
with us. I
understand that if you check artwork prior to the date concerned
there is
ample evidence that what is now the Sahara was very fruitful land
beforehand, then suddenly it all became desert. As I understand
it,
Egyptologists put this down to effects of some sudden influx of
vulcanism
somewhere, but it may well be that a bit off Hale Bopp helped
cause this.
I guess the 100 year confusion in the states concerned was simply
the time
they took to get used to the changes.
Best wishes, Andy Nimmo.
===========
(9) BACKGROUND: COMETS AND DISASTER IN THE BRONZE AGE
From BRITISH ARCHAEOLOGY, The Journal of the Council for British
Archaeology, December 1997
http://www.knowledge.co.uk/sis/ba9712bp.htm
Cometary impact is gaining ground as an explanation of the
collapse of
civilisations, writes Benny Peiser
At some time around 2300 BC, give or take a century or two, a
large number
of the major civilisations of the world collapsed, simultaneously
it seems.
The Akkadian Empire in Mesopotamia, the Old Kingdom in Egypt, the
Early
Bronze Age civilisation in Israel, Anatolia and Greece, as well
as the Indus
Valley civilisation in India, the Hilmand civilisation in
Afghanistan and
the Hongshan Culture in China - the first urban civilisations in
the world -
all fell into ruin at more or less the same time. Why?
A thousand years later, at around 1200 BC, many of the
civilisations of the
same regions again collapsed at about the same time. This time,
disaster
overtook the Myceneans of Greece, the Hittites of Anatolia, the
Egyptian New
Kingdom, Late Bronze Age Israel, and the Shang Dynasty of China.
The reasons for these widespread and apparently simultaneous
disasters -
which coincided also with changes of cultures and societies
elsewhere, such
as in Britain - have long been a fascinating mystery. Traditional
explanations include warfare, famine, and more recently 'system
collapse',
but the apparent absence of direct archaeological or written
evidence for
causes, as opposed to the effects, has led many archaeologists
and
historians into a resigned assumption that no definite
explanation can
possibly be found.
Some decades ago, the hunt for clues passed largely into the
hands of
natural scientists. Concentrating on the earlier set of Bronze
Age
collapses, researchers began to find a range of evidence that
suggested that
natural causes rather than human actions, may have been initially
responsible. There began to be talk of climate change, volcanic
activity,
and earthquakes - and some of this material has now found its way
into
standard historical accounts of the period.
Agreement, however, there has never been. Some researchers
favoured one type
of natural cause, others favoured another, and the problem
remained that no
single explanation appeared to account for all the evidence.
Over the past 15 years or so, however, a new type of 'natural
disaster' has
been much discussed and is beginning to be regarded, by many
scholars, as
the most probable single explanation for widespread and
simultaneous
cultural collapse, but not only in the Bronze Age but at another
times as
well. The new theory has been advanced largely by astronomers,
and remains
almost completely unknown amongst archaeologists (a few notable
exceptions
include the dendrochronologist Prof Mike Baillie of Queen's
University,
Belfast, and Dr Euan MacKie at Glasgow University). The new idea
is that
these massive cultural disasters were caused by the impact of
comets or
other types of cosmic debris on the Earth.
The hunt for natural causes for these human disasters began when
the
Frenchman Claude Schaeffer, one of the leading archaeologists of
his time,
published his book Stratigraphie Comparee et Chronologie L'Asie
Occidentale
in 1948. Schaeffer analysed and compared the destruction layers
of more than
40 archaeological sites in the Near and Middle East, from Troy to
Tepe
Hissar on the Caspian Sea and from the Levant to Mesopotamia. He
was the
first scholar to detect that all had been totally destroyed
several times in
the Early, Middle and Late Bronze Age, apparently simultaneously.
Since the
damage was far too excessive and did not show signs of military
or human
involvement, he argued that repeated earthquakes might have been
responsible
for these events.
At the time he published, Schaeffer was not taken seriously by
the world of
archaeology. Since then, however, natural scientists have found
widespread
and unambiguous evidence for abrupt climate change, sudden sea
level
changes, catastrophic inundations, widespread seismic activity
and evidence
for massive volcanic activity at several periods since the last
Ice Age, but
particularly at around 2200BC, give or take 200 years. Areas such
as the
Sahara, or around the Dead Sea, were once farmed but became
deserts. Tree
rings show disastrous growth conditions at c 2350BC, while
sediment cores
from lakes and rivers in Europe and Africa show a catastrophic
drop in water
levels at this time. In Mesopotamia, vast areas of land appear to
have been
devastated, inundated, or totally burned.
Scholars who, following Schaeffer, favour earthquakes as the
principal cause
of civilisation collapse argue that the world can expect vast
earthquakes
every 1000 - 2000 years, leading to widespread abandonment of
sites; while
scholars who prefer climate change as the principal cause argue
that severe
droughts caused agriculture to fail and that societies inexorably
fell apart
as a result.
Yet what was the cause of these earthquakes, eruptions, tidal
waves,
fire-blasts and climate changes? By the late 1970s, British
astronomers
Victor Clube and Bill Napier of Oxford University had begun to
investigate
cometary impact as the ultimate cause. Then in 1980, the Nobel
prizewinning
physicist Luis Alvarez and his colleagues published their famous
paper in
Science that argued that a cosmic impact had led to the
extinction of the
dinosaurs. He showed that large amounts of the element iridium
present in
geological layers dating from about 65 million BC had a cosmic
origin.
Alvarez's paper had immense influence and stimulated further
research by
such British astronomers as Clube and Napier, Prof Mark Bailey of
the Armagh
Observatory, Duncan Steel of Spaceguard Australia, and Britain's
best known
astronomer Sir Fred Hoyle. All now support the theory of cometary
impact and
loosely form what is now known as the British School of Coherent
Catastrophism.
These scholars envisage trains of cometary debris which
repeatedly encounter
the Earth. We know that tiny particles of cosmic material
penetrate the
atmosphere every day, but their impact is insignificant.
Occasionally,
however, cosmic debris measuring between one and several hundred
metres in
diametre strike the Earth and these can have catastrophic effects
on our
ecological system, through multimegaton explosions of fireballs
which
destroy natural and cultural features on the surface of the Earth
by means
of tidal-wave floods (if the debris lands in the sea), fire
blasts and
seismic damage.
Depending on their physical properties, asteroids or comets that
punctuate
the atmosphere can either strike the Earth's surface and leave
and impact
crater, such as the well-known Barringer Crater in Arizona caused
by an
asteroid made of iron some 50,000 years ago. At least ten impact
craters
around the world dating from after the last Ice Age, and no fewer
than seven
of these date from around the 3rd millennium BC - the date of the
widespread
Early Bronze Age collapses - although none occurred in the Near
East.
Alternatively, comets and asteroids can explode in the air. A
recent example
- known as the Tunguska Event - occurred in 1908 over Siberia,
when a bolide
made of stone exploded about 5km above ground and completely
devastated an
area of some 2,000 km' through fireball blasts. The cosmic body,
although
thought to have measured only 60 m across, had an impact energy
of about 20
to 40 megaton, up to three times as great as the Arizona example
(about 15
megaton), and was equivalent to the explosion of about 2,000
Hiroshima-size
nuclear bombs - even though there was no actual physical impact
on the
Earth.
(The object that destroyed the dinosaurs, by contrast, is thought
to have
had a diametre of about 10km.) A smaller cometary blast occurred
over the
Brazilian rainforest in 1930.
In addition to the physical impact of comets, the British
astronomers point
to occasional massive influx of cosmic dust high above the
stratosphere
which can cause a dramatic drop of global temperature, leading to
the
suspension of agriculture; and also the massive influx of cosmic
chemicals
(associated with dust) with, as yet, incalculable biochemical
potentials but
which may be harmful to DNA and can trigger evolutionary
mutations.
Until recently, the astronomical mainstream was highly critical
of Clube and
Napier's giant comet hypothesis. However, the crash of comet
Shoemaker-Levy
9 on Jupiter in 1994 has led to a change in attitudes. The comet,
watched by
the world's observatories, was seen split into 20 pieces and slam
into
different parts of the planet over a period of several days. A
similar
impact on Earth, it hardly needs saying, would have been
devastating.
According to current knowledge, Tunguska-like impacts occur every
100 years
or so. It is, therefore, not farfetched to hypothesise that a
super-Tunguska
may occur every 2000, 3000 or 5000 years and would be capable of
triggering
ecological crises on a continental or even global scale. In the
past,
skeptics have demanded the evidence of a crater before they would
accept an
argument of cosmic impact, but it is now become understood that
no crater is
necessary for disastrous consequences to ensue. The difficulty
this leaves
scholarship, however, is that in a Tunguska Event no direct
evidence is left
behind. It may be impossible to prove that one ever took place in
the
distant past.
The extent to which past cometary impacts were responsible for
civilisation
collapse, cultural change, even the development of religion, must
remain a
hypothesis. But in view of the astronomical, geological and
archaeological
evidence, this 'giant comet' hypothesis should no longer be
dismissed by
archaeologists out of hand.
Dr Benny J Peiser is a historian and anthropologist at Liverpool
John Moores
University. With Mark Bailey and Trevor Palmer, he edited
"Natural
Catastrophes during Bronze Age Civilisations"
http://www.knowledge.co.uk/sis/cambconf.htm(Oxford:
British Archaeological
Reports, 1998)
===========
(10) BACKGROUND II: BEYOND THE YOUNGER DRYAS: COLLAPSE AS
ADAPTATION TO
ABRUPT CLIMATE CHANGE
By Harvey Weiss, Professor of Near Eastern Archaeology, Yale
University
http://www.yale.edu/nelc/weiss/byd.html
BEYOND THE YOUNGER DRYAS
Collapse as Adaptation to Abrupt Climate Change in Ancient West
Asia and the
Eastern Mediterranean
[In Confronting Natural Disaster: Engaging the Past to Understand
the
Future, G. Bawden and R. Reycraft, editors, pp. 75-98. University
of New
Mexico Press, Albuquerque, 2000.]
Harvey Weiss
"Although Holocene climate events are relatively minor on a
glacial/interglacial perspective, the small Holocene changes in
the polar
vortex and atmospheric storminess
documented by O'Brien et al. (1995) would probably cause
widespread
disruption to human society if they were to occur in the
future"
(Keigwin and Boyle 2000:1343).
The earliest Holocene abrupt climate changes occurred at 12,800,
8200, 5200,
and 4200 B.P. The 4200 B.P. abrupt climate change is especially
well
documented across West Asia, Central Asia, Africa, and parts of
the New
World. Limnological and speleothem radiometric dates situate the
beginning
of this event at ca. 3800 radiocarbon years before 1950 (3.8 ka
bp) or ca.
2200 B.C. High resolution paleoclimate records, including the
Greenland Ice
Sheet Project 2 (GISP2) ice core, Lake Van varve sediments, and
U.S.
Southwest dendrochronology now also provide absolute calendar
dating for
this event in addition to quantification of its amplitude
relative to prior
and succeeding climate states. Social adaptations to this event
are recorded
in the contemporary archaeological records of southeastern
Europe, North
Africa, and West Asia: habitat-tracking, regional population
abandonments,
migrations, and sociopolitical collapse.
PALEOENVIRONMENTAL RECORDS
The Holocene abrupt climate changes, hemispheric and global in
extent, were
of lesser magnitude than those characteristic of the Pleistocene,
but they
profoundly disrupted late hunter-gatherer, pastoral, and
agriculture-based
societies within various environments and at various levels of
socioeconomic
hierarchization, centralization, and regional command. These
climate changes
were natural, not anthropogenic, and therefore add a new string
of variables
to the analysis of agro-pastoral production and politico-economic
process
within prehistoric and early historic West Asia.
The earliest of the Holocene abrupt climate changes (Figure 21)
was the
Younger Dryas interval, dated by GISP2 to ca. 12,800-11,500 B.P.
, which
quickly created a colder and drier Arctic, North Atlantic,
Europe, North
America, and West Asia after a thousand-year period of
post-Pleistocene
climate amelioration (Alley 2000; Peteet 2000). The effects of
this climate
change on humans--and possibly Hordeum and Triticum populations
as well
(Rossignol-Strick 1999)--were radical. Hunting and gathering
bands were
forced to adapt to rapid drying and cooling of niches where wild
plants and
animals had formerly provided abundant subsistence (Bar-Yosef and
Belfer-Cohen 1992; Moore and Hillman 1992). The decreased annual
yields of
wild cereal stands increased both the need and the motivation for
cultivation. In the face of rapidly altered environments, human
subsistence
procurement was extended to adjacent areas less affected by
Younger Dryas
drying and cooling. This habitat-tracking (Coope 1979) comprised
the first
stages to agriculture in the steppic Levant (Bar-Yosef 1998) and
probably in
the steep isohyet gradient Habur Plains that lie north of the
Jebel Sinjar
and Radd Swamp in northern Mesopotamia (Weiss 1997). Other
regions of West
Asia no doubt also experienced Younger Dryas alterations of late
hunter-gatherer subsistence as 2º-10ºC cooling occurred
rapidly, with the
subsequent warming transforming the region again within less than
a decade
(Peteet 2000). Younger Dryas habitats were the stage, therefore,
for
collapse of late hunter-gatherer society as more labor-intensive
agriculture
was required for subsistence in contiguous areas suitable for dry
farming.
The second major abrupt Holocene climate change occurred at ca.
8200 B.P.,
lasted four hundred years (6400-6000 B.C.) and, like the Younger
Dryas,
generated abrupt aridification and cooling in the North Atlantic
and North
America, Africa, and Asia (Alley et al. 1997; Barber et al. 1999;
Hu et al.
1999; Street-Perrot and Perrot 1990). This event is well-known
from the
GISP2 analyses, within which it is second only to the Younger
Dryas in
magnitude of some measurable variables (Alley et al. 1997; Figure
22). The
pronounced West Asian signal for the 8200 B.P. event is present
in Soreq
Cave speleothem records (Bar-Matthews et al. 1999), Negev snail
isotope
variability (Goodfriend 1991, 1999), low Dead Sea levels (Frumkin
et al.
1994), and the geochemistry of stage E to stage F transition at
Lake Van
(Lemcke and Sturm 1997), but absent from the Gulf of Oman core
(Cullen et
al. 2000). Climate deterioration in the eastern Mediterranean at
this time
is, perhaps, also expressed by decrease of Pistacia and Quercus
at Tenaghi
Phillipon (Wijmstra 1969) and the Adriatic (Rohling et al 1997;
Rossignol-Strick 1999; Rossignol-Strick et al. 1982).
During this period in the Levant most Pre-Pottery Neolithic B
village
settlements were abandoned. Successor settlements displayed a new
dependence
upon sheep pastoralism understood to be an adaptation to expanded
areas of
decreased rainfall (Goring-Morris 1994; Goring-Morris and
Belfer-Cohen
1997). In northern Mesopotamia, this climatic oscillation may
have induced
the transfer of Umm Dabaghiyah culture to refuge areas (Kozlowski
1994), and
the subsequent appearance and expansion of Hassuna and Samarran
cultures
with the amelioration of climate conditions. The radiocarbon
chronology for
this period, however, requires refinement. In southern
Mesopotamia Late
Samarran settlement extended to the delta floodplain (Forest
1983, 1999;
Huot 1989). This extension of settlement may have been the
response of
Samarran agriculturalists to changes in both annual precipitation
and
seasonal Euphrates flow. In comparison with occupation of the
alluvial
plain, settlement further south in the delta provided easier
access to
controllable river flow, with shallower channels and slower
stream flow
facilitating water storage through the manipulation of seasonal
basins and
river levees.
The third abrupt climate change occurred at 5200 B.P. (3200-3000
B.C.), and
was also a century-scale, rapid, drying/cooling event (C on
Figure 22). In
West Asia the event is recorded in Lake Van varves (Lemcke and
Sturm 1997),
Gulf of Oman sediments (Cullen et al. 2000), and Soreq Cave
speleothems
(Bar-Matthews et al. 1999; Figure 23). The absence of any signal
for this
event in the West Asian lake core pollen analyses (Bottema 1997)
is not
unusual as these analyses have provided only irregular detection
of Holocene
climate changes. The uniform definition of this event at Lake
Van, Soreq
Cave, and the Gulf of Oman seems to mark a regionwide event,
perhaps
synchronous with, and a function of, the abrupt termination of
the African
Humid Period at ca. 3500 B.C. (Baker and Yarusinsky 2000;
deMenocal et al.
2000). The magnitude of this event at Lake Van, the Gulf of Oman,
and Soreq
Cave suggests a profound role for climate change in Uruk period
processes
and events, including:
* terminal Uruk period urbanization in southern Mesopotamia
(Adams
1981:94)
* the indigenous late Ubaid-early Uruk expansion and nucleation
of
settlement in northern Mesopotamia (Weiss 1997)
* the genesis and collapse of the Uruk "colonies"
(Johnson 1988)
The 5200 B.P./Late Uruk abrupt climate change also altered
environments and
subsistence outside the Mesopotamian lowlands. The
Kura-Araxes/Khirbet Kerak
intrusion into the Iranian and the Anatolian plateaus interrupted
both
colony (Weiss and Young 1975) and indigenous state-level
(Frangipane 1997)
development during the last centuries of the fourth millennium.
Why this
population movement occurred at this time, and why it took its
distinctive
path, are questions raised anew by Frangipane's retrieval of the
"royal
cemetery" at Arslantepe.
THIRD MILLENNIUM B.C. ABRUPT CLIMATE CHANGE
Archaeological data had led both Mellaart (1966) and Bell (1971)
to
hypothesize a late third millennium aridification event.
Archaeological and
soil micromorphology data from Tell Leilan, and in comparison
with data from
other regions, fixed the event across West Asia at the time of
the Akkadian
collapse (Weiss et al. 1993). Confirmation was seen in the
additional Old
World lake levels, from West Africa to West Tibet, abruptly
declining at ca.
3.8 ka bp (Gasse and van Campo 1994).
High-resolution paleoclimate data now further refine this event.
Other
paleoclimate records, including some of similar resolution,
indicate the
event's global extent. The relatively well defined archaeological
record for
West Asia preserves the social responses of prehistoric and early
historic
societies to this abrupt climate change. Here the proxy data
within the most
significant high resolution records for the Mediterranean
westerlies,
Mesopotamia, and the Indian monsoon are summarized.
FULL PAPER at http://www.yale.edu/nelc/weiss/byd.html
=========
(11) AND FINALLY A RATHER FRUITLESS QUESTION: BEFORE THE BIG
BANG, THERE WAS
... WHAT?
From The New York Times, 22 May 2001
http://www.nytimes.com/2001/05/22/science/22BANG.html
By DENNIS OVERBYE
What was God doing before he created the world? The philosopher
and writer
(and later saint) Augustine posed the question in his
"Confessions" in the
fourth century, and then came up with a strikingly modern answer:
before God
created the world there was no time and thus no
"before." To paraphrase
Gertrude Stein, there was no "then" then.
Until recently no one could attend a lecture on astronomy and ask
the modern
version of Augustine's question - what happened before the Big
Bang? -
without receiving the same frustrating answer, courtesy of Albert
Einstein's
general theory of relativity, which describes how matter and
energy bend
space and time.
If we imagine the universe shrinking backward, like a film in
reverse, the
density of matter and energy rises toward infinity as we approach
the moment
of origin. Smoke pours from the computer, and space and time
themselves
dissolve into a quantum "foam." "Our rulers and
our clocks break," explained
Dr. Andrei Linde, a cosmologist at Stanford University. "To
ask what is
before this moment is a self-contradiction."
But lately, emboldened by progress in new theories that seek to
unite
Einstein's lordly realm with the unruly quantum rules that govern
subatomic
physics - so-called quantum gravity - Dr. Linde and his
colleagues have
begun to edge their speculations closer and closer to the
ultimate moment
and, in some cases, beyond it.
Some theorists suggest that the Big Bang was not so much a birth
as a
transition, a "quantum leap" from some formless era of
imaginary time, or
from nothing at all. Still others are exploring models in which
cosmic
history begins with a collision with a universe from another
dimension.
All this theorizing has received a further boost of sorts from
recent
reports of ripples in a diffuse radio glow in the sky, thought to
be the
remains of the Big Bang fireball itself. These ripples are
consistent with a
popular theory, known as inflation, that the universe briefly
speeded its
expansion under the influence of a violent antigravitational
force, when it
was only a fraction of a fraction of a nanosecond old. Those
ripples thus
provide a useful check on theorists' imaginations. Any theory of
cosmic
origins that does not explain this phenomenon, cosmologists
agree, stands
little chance of being right.
Fortunately or unfortunately, that still leaves room for a lot of
possibilities.
"If inflation is the dynamite behind the Big Bang, we're
still looking for
the match," said Dr. Michael Turner, a cosmologist at the
University of
Chicago. The only thing that all the experts agree on is that no
idea works
- yet. Dr. Turner likened cosmologists to jazz musicians
collecting themes
that sound good for a work in progress: "You hear something
and you say, oh
yeah, we want that in the final piece."
One answer to the question of what happened before the Big Bang
is that it
does not matter because it does not affect the state of our
universe today.
According to a theory known as eternal inflation, put forward by
Dr. Linde
in 1986, what we know as the Big Bang was only one out of many in
a chain
reaction of big bangs by which the universe endlessly reproduces
and
reinvents itself. "Any particular part of the universe may
die, and probably
will die," Dr. Linde said, "but the universe as a whole
is immortal."
Dr. Linde's theory is a modification of the inflation theory that
was
proposed in 1980 by Dr. Alan Guth, a physicist. He considered
what would
happen if, as the universe was cooling during its first violently
hot
moments, an energy field known as the Higgs field, which
interacts with
particles to give them their masses, was somehow, briefly, unable
to release
its energy.
Space, he concluded, would be suffused with a sort of latent
energy that
would violently push the universe apart. In an eyeblink the
universe would
double some 60 times over, until the Higgs field released its
energy and
filled the outrushing universe with hot particles. Cosmic history
would then
ensue.
Cosmologists like inflation because such a huge outrush would
have smoothed
any gross irregularities from the primordial cosmos, leaving it
homogeneous
and geometrically flat. Moreover, it allows the whole cosmos to
grow from
next to nothing, which caused Dr. Guth to dub the universe
"the ultimate
free lunch."
Subsequent calculations ruled out the Higgs field as the
inflating agent,
but there are other inflation candidates that would have the same
effect.
More important, from the pre- Big-Bang perspective, Dr. Linde
concluded, one
inflationary bubble would sprout another, which in turn would
sprout even
more. In effect each bubble would be a new big bang, a new
universe with
different characteristics and perhaps even different dimensions.
Our
universe would merely be one of them.
"If it starts, this process can keep happening
forever," Dr. Linde
explained. "It can happen now, in some part of the
universe."
The greater universe envisioned by eternal inflation is so
unimaginably
large, chaotic and diverse that the question of a beginning to
the whole
shebang becomes almost irrelevant. For cosmologists like Dr. Guth
and Dr.
Linde, that is in fact the theory's lure.
"Chaotic inflation allows us to explain our world without
making such
assumptions as the simultaneous creation of the whole universe
from
nothing," Dr. Linde said in an e-mail message.
Questions for Eternity
Trying to Imagine the Nothingness
Nevertheless, most cosmologists, including Dr. Guth and Dr.
Linde, agree
that the universe ultimately must come from somewhere, and that
nothing is
the leading candidate.
As a result, another tune that cosmologists like to hum is
quantum theory.
According to Heisenberg's uncertainty principle, one of the
pillars of this
paradoxical world, empty space can never be considered really
empty;
subatomic particles can flit in and out of existence on energy
borrowed from
energy fields. Crazy as it sounds, the effects of these quantum
fluctuations
have been observed in atoms, and similar fluctuations during the
inflation
are thought to have produced the seeds around which today's
galaxies were
formed.
Could the whole universe likewise be the result of a quantum
fluctuation in
some sort of primordial or eternal nothingness? Perhaps, as Dr.
Turner put
it, "Nothing is unstable."
The philosophical problems that plague ordinary quantum mechanics
are
amplified in so-called quantum cosmology. For example, as Dr.
Linde points
out, there is a chicken- and-egg problem. Which came first: the
universe, or
the law governing it? Or, as he asks, "If there was no law,
how did the
universe appear?"
FULL STORY at http://www.nytimes.com/2001/05/22/science/22BANG.html
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