PLEASE NOTE:
*
CCNet DIGEST, 6 November 1998
-----------------------------
(1) STUDENT'S RESEARCH SUPPORTS THEORY OF ANCIENT METEOR STRIKE
Andrew Yee <ayee@nova.astro.utoronto.ca>
(2) FIRST ROTATION PERIOD OF KUIPER BELT OBJCET MEASURED
Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
(3) NATURAL CATASTROPHES DURING BRONZE AGE CIVILISATIONS
Ian Tresman <ian@knowledge.co.uk>
(4) 'SMALL' OCEANIC IMPACTORS (>1km) POSE NO SIGNIFICANT
TSUNAMI
THREAT, US SCIENTISTS CLAIM
Michael Paine <mpaine@tpgi.com.au>
(5) THE DINOSAURS BEQUEST
Andrea Milani Comparetti <milani@copernico.dm.unipi.it>
(6) NUMERICAL MODEL PREDICTIONS FOR 1998 LEONIDS
Juergen Rendtel <jrendtel@aip.de> [posted on
the imo-list]
(7) SEARCHING FOR ANSWERS TO SOLAR MYSTERIES
NASA Science News <expressnews@sslab.msfc.nasa.gov>
(8) THE EVOLUTION OF THE HUMAN BRAIN: IS BIGGER BETTER?
M. Henneberg, UNIVERSITY OF ADELAIDE
================
(1) STUDENT'S RESEARCH SUPPORTS THEORY OF ANCIENT METEOR STRIKE
From Andrew Yee <ayee@nova.astro.utoronto.ca>
Univeristy of Memphis
Memphis, Tennessee
For more information:
Les Seago, email: lseago@cc.memphis.edu,
901-678-2843
Student's Research Supports Theory of Ancient Meteor Strike
A recent University of Memphis graduate has uncovered evidence
that
a 65-million-year-old meteor strike in Mexico may have moved
massive
boulders to the top of 250-foot hills in what is now the
Mid-South.
Gary L. Patterson's research tends to confirm scientists' belief
that a 10-kilometer-wide meteor struck on the east coast of
Mexico's
Yucatan Peninsula some 65 million years ago, throwing debris
thousands of miles and creating a huge tsunami wave in the Gulf
of
Mexico. Patterson, who received a master's degree in geology at
The
U of M in August, says he has found large rocks at several
Mid-South
sites that appear to have been picked up by the tsunami and
thrown
into unlikely locations.
"A tsunami wave is one of the few things with enough energy
to move
those 50-foot-wide boulders to the top of a hill 250 feet above
the
flood plain," says Patterson, who is now a staff member at
The
University's Center for Earthquake Research and Information.
Patterson will present his findings Oct. 27 at the Geological
Society of America's annual meeting in Toronto.
Patterson began his study of the Yucatan meteor's crash more than
six years ago as an undergraduate student at The U of M. After
studying scientific literature dealing with the meteor strike, he
began looking for evidence of the debris in several Mid-South
states. The Arkansas Geological Commission provided information
that
led to his examination of the sites.
Scientists say that when the meteor hit along the Yucatan coast,
it
created a huge crater and tossed pieces of molten rock hundreds
of
miles away. At that time, the Gulf of Mexico extended deep into
the
central United States in what is known as the Mississippi
Embayment.
The embayment, which covered an area from where Cairo, Ill., is
now
located on the north, to Central Arkansas on the west and the
Tennessee River on the east, was beneath hundreds of feet of
water.
Over the millennia , the embayment has been filled in with more
than
3,000 feet of soil deposits from rivers and runoff from ice age
glaciers.
Previous geological research has found glassy debris from the
meteor
in Texas, Arkansas and Oklahoma, and Patterson looked
unsuccessfully
for similar debris in the Mississippi Embayment. Any meteor
debris,
he said, was probably buried deep beneath the soil.
But at three of the 17 sites in Arkansas, Tennessee, Mississippi
and
Missouri that Patterson studied, he found large rocks at higher
levels than could be easily explained.
The rocks, of oceanic sandstone, rest in beds of gravel and
smaller
rocks that did not match other nearby rock formations, he said.
The
large rocks, some of them 50 feet or more in diameter, were found
in
an area that would have been along the shore of the embayment
when
the meteor struck the Yucatan Peninsula.
Patterson said there are few natural forces that could move such
huge boulders atop hills.
"We ruled out glaciers, because the glaciers didn't come
this far
south," he said. "A river couldn't lift a rock that big
to the top
of a 250-foot hill. Even a flood stage, a river couldn't move a
boulder. A Tsunami wave is one of the few things with the energy
to
pick up a boulder and deposit it on the highland rim."
=====================
(2) FIRST ROTATION PERIOD OF KUIPER BELT OBJCET MEASURED
From Ron Baalke <BAALKE@kelvin.jpl.nasa.gov>
ESO Education and Public Relations Dept.
----------------------------------------------------------------------------
Text with all links is available on the ESO Website at URLs:
http://www.eso.org/outreach/press-rel/pr-1998/phot-41-98.html
----------------------------------------------------------------------------
ESO Press Photo 41/98
For immediate release: 5 November 1998
First Rotation Period of a Kuiper Belt Object Measured
News from ESO Workshop on Minor Bodies in the Outer Solar System
An ESO Workshop on Minor Bodies in the Outer Solar System
(ESO
MBOSS-98) was held at the ESO Headquarters in Garching, Germany,
during November 2-5, 1998. Among these objects, the newly
discovered
Kuiper Belt Objects (KBO's) outside the orbit of planet Neptune
(also known as Trans-Neptunian Objects) are of particular
interest,
but the meeting was also concerned with distant comets and some
of
the small moons of the outer planets.
During these four days, about 50 specialists from all parts of
the
world, observers as well as theoreticians, had a very fruitful
discussion about this rapidly expanding research field. In
particular, they identified some of the crucial questions for
which
answers are required in order to advance our overall picture of
the
formation, evolution and interaction of these distant bodies.
Specific plans were made for collaborative studies of the outer
Solar System during the coming years.
The workshop served to review and discuss current knowledge of
all
minor bodies beyond the asteroid belt, as well as their origins
and
inter-relationships. Special emphasis was placed on the optimal
use
of next-generation observational facilities, such as the ESO Very
Large Telescope (VLT) at the Paranal Observatory (Chile) and the
Keck telescope at Mauna Kea (Hawaii, USA). The participants
enthusiastically identified several front-line observational
investigations that will take full advantage of these powerful
astronomical facilities.
Kuiper Belt Objects
The Kuiper Belt is a zone outside the orbits of Neptune and Pluto
in
which icy solar system objects were expected to be present; the
first was found in 1992. Since then, more than 70 KBO's have been
found in orbits between approximately 30 AU and 50 AU from the
Sun
(4.5 to 7.5 x 10^9 km). One of them (designated 1996 TL66) even
reaches a distance of 135 AU (20 x 10^9 km, i.e. 4.5 times the
heliocentric distance of Neptune) when it is farthest away. It is
estimated that there may be at least 100,000 KBO's larger than
100 km.
These objects probably represent the remnants of a much larger
population of such objects, formed in the early phase of the
solar
system, some 4.5 billion years ago. Gravitational effects from
the
outer planets Neptune and Uranus and collisions soon reduced
their
numbers. The outermost planet Pluto is most probably the largest
member of this class of objects.
Because of their large distance, and despite their significant
size,
100 - 500 km diameter, they are all very faint and can only be
observed with large telescopes. Except for their orbits, little
is
known about most of them, although recent observations have shown
that they have different colours, ranging from rather blueish to
red.
According to current ideas, the short period comets observed in
the
inner solar system come from the Kuiper Belt and their
kilometre-size "dirty snowball" nuclei are simply small
KBO's.
First rotational period of a KBO measured at La Silla
Among the highlights of this workshop was the presentation of a
detailed portrait of a Kuiper-Belt Object, designated as 1996
TO66.
It was discovered in October 1996 by a group of astronomers from
the
University of Hawaii, during a survey aimed at discovering KBO's.
It
is one of the brightest trans-neptunian objects known to date;
its
magnitude is 21.2, i.e. it is about 1.5 million times fainter
than
the faintest stars visible by naked eye.
A group of European astronomers [1] used the ESO 3.6-m New
Technology Telescope (NTT) at the La Silla observatory during 6
nights in August and October 1997 to obtain very accurate
observations of 1996 TO66, while is was at a distance of about 45
AU.
The top panel shows a composite image of the Kuiper Belt Object
1996
TO66 (round image at the center), totalling 4 hours of exposure
with
the EMMI multi-mode instrument at the 3.6-m New Technology
Telescope
(NTT) at La Silla. During the exposure, the object moved with
respect to the background stars; this motion was compensated for
and
the KBO therefore appears as a point, while the images of
background
stars are trailed. The bright, nearly horizontal line that
crosses
the entire field is the light trail left by a geostationary
satellite in orbit around the Earth, that crossed the field of
view
during one of the exposures (this also serves to illustrate a
specific problem of modern astronomy -- that of increasing
"light
pollution" from artificial satellites illuminated by the
Sun). The
lower panel is the composite "light-curve" of 1996
TO66, showing its
brightness ("red magnitude") variations with time (in
hours). The
dots and the corresponding "error bars" represent the
actual
measurements from several nights and their uncertainties, while
the
solid line is a mathematic fit through these points. It was used
to
determine the rotation period of 1996 TO66 as about 6 hours and
15
minutes.
During these nights, they took over 50 images of the object
through
different optical filters; on each of these, they carefully
measured
its brightness. The resulting "light-curve", cf. ESO PR
Photo 41/98,
i.e. the change of brightness with time, shows a clear variation
with a period of a little over 6 hours. This is caused by
rotation
of the object. It is the first time it has been possible to
determine a rotation period of any KBO.
From the mean brightness of 1996 TO66, it was estimated that the
diameter is of the order of 600 km. This corresponds to just
under
one third of the size of the outermost planet Pluto, making 1996
TO66 one of the largest known KBO's. The light-curve also
indicates
that the object is somewhat elongated (one axis is at least 10%
larger than the others), and that the surface may possibly have
some
darker and brighter regions.
Implications
This first measurement of the rotation period of a KBO is
important:
as 1996 TO66 is a comparatively large body, it is most likely
that
the rotation period has not changed much since its formation, 4.5
billion years ago. This is one more precious piece of information
to
our still very sparse knowledge about the processes that took
place
when our solar system was formed. Interestingly, (2060) Chiron, a
minor planet in orbit between Saturn and Uranus that is thought
to
have originally come from the Kuiper Belt, also rotates with a
period near 6 hours.
A comparison of 1996 TO66's brightness as measured through
different
optical filters, indicates that it is of a grey-blue colour,
similar
to that of Pluto's moon, Charon, and also the KBO 1996 TL66.
Very little is still known about the physical nature of the
KBO's.
They are so remote and faint that their study, even with large
telescopes, is near the observational limits of what is possible.
Nevertheless, new results like these now pave the way towards a
better understanding of the current population of minor bodies in
the outer reaches of our solar system.
When more observations of KBO's with large telescopes like the
VLT
become available during the next years, it is expected that
trends
in their measured physical properties (e.g. rotational state,
surface properties) will emerge. This will in turn permit more
specific conclusions about the structure of the proto-planetary
disk
and the processes by which the planets and the KBO's were formed.
Note:
[1] The group consists of Olivier Hainaut, Catherine Delahodde
and
Hermann Boehnhardt (ESO La Silla) and Elisabetta Dotto and Maria
Antonietta Barucci (Observatoire de Paris).
------------------------------------------------------------------------
Copyright ESO
Education & Public Relations Department
Karl-Schwarzschild-Strasse
2, D-85748 Garching, Germany
======================
(3) NATURAL CATASTROPHES DURING BRONZE AGE CIVILISATIONS
From Ian Tresman <ian@knowledge.co.uk>
Information about the Proceedings of the Second SIS Cambridge
Conference are now available on the SIS Web site at:
http://www.knowledge.co.uk/sis/cambproc.htm
The page includes full details of pricing and ordering from the
SIS.
Regards,
Ian
=====================
(4) 'SMALL' OCEANIC IMPACTORS (>1km) POSE NO SIGNIFICANT
TSUNAMI
THREAT, US SCIENTISTS CLAIM
From Michael Paine <mpaine@tpgi.com.au>
Sandia National Laboratories will soon be releasing the results
of a
comprehensive study of tsunami produced by small asteroids. These
latest simulations reveal that the tsunamis generated by such
impacts are considerably smaller (possibly by orders of
magnitude)
than indicated on my web page
http://www1.tpgi.com.au/users/tps-seti/spacegd7.html.
The researchers conclude that only large impactors pose a
significant threat for an entire ocean basin (something greater
than
1-2km) and that small atmosphere-exploding impacts will produce
only
local effects and negligible tsunami. If this is the case then my
calculations of risk from tsunmai generated by asteroids are
likely
to be invalid (and the web page will need substantial revision)!
Even if asteroid impacts are not a likely cause of tsunami on
timescales of thousands of years the questions remain - what
caused
the 6 large tsunami along the New South Wales coast over the past
6,000 years and should Australian coastlines have tsunami warning
systems? Finally, the cost-effectiveness calculations in the
proposal for reviving a Spaceguard program in Australia were
based
on large impacts and are unaffected by tsunami issues.
Regards
Michael Paine mailto:mpaine@tpgi.com.au
============
(5) THE DINOSAURS BEQUEST
From Andrea Milani Comparetti <milani@copernico.dm.unipi.it>
Dear Benny, and dear Bill,
I know that I have the reputation of a hard line scientist,
writing
papers with too much mathematics... but I also have a soft
side.
You might be amused to know that I also have writen a Science
Fiction novel with a subject related to our common interest in
asteroid/comet impacts.
The novel has title "The dinosaurs bequest", and
discusses the
extinction of dinosaurs, which are (of course, it is SF) assumed
to
have had an advanced technological civilisation, and nevertheless
they have not been able to divert the Chicxulub impactor...
After the debate held on your mailing list in the recent days,
you
can easily guess the solution, which is suggested to the main
characters by the consultation of a very old man, formerly
engaged
in the Spaceguard Survey. The novel also discusses the genetic
engineering experiments done by the dinosaurs on mammals, and the
style of virtual reality used, not only for for research
purposes,
in the world of the years 2040, flooded by the melting of the
polar
caps.
Thus my novel has the excessive ambition of being at once an
answer
to Jurassic Park, to Deep Impact (although it was written before)
and to the cyberpunk genre; it is also an entry in the debate
about
use and abuse of asteroid deflection technology.
Where can you read this novel? Theoretically, you can consult the
online version at
http://copernico.dm.unipi.it/~milani/fantascienza/eredi21l/eredi21l.html
The problem, however, and the reason for this message (besides
pure
vanity), is that my novel is written in Italian. I have written
thousands of pages of scientific papers (and even textbooks) in
English, but to translate a novel is an entirely different job.
Is
it possible to find someone out there (maybe among the readers of
the Cambridge Conference) who could help me in this difficult
task?
The problem is, most professional translators do not have the
scientific competence to translate correctly the scientific (and
para-scientific) arguments, while I do not have the familiarity
with
literary English which would be required for an acceptable
translation.
Yours
Andrea Milani
Dipartimento di Matematica
Via Buonarroti 2
56127 PISA ITALY
tel. +39-50-844254 fax +39-50-844224
E-mail: milani@dm.unipi.it
WWW: http://virmap.unipi.it/~milani/homemilani.html
================================================
(6) NUMERICAL MODEL PREDICTIONS FOR 1998 LEONIDS
From Juergen Rendtel <jrendtel@aip.de>
[psoted on the imo-list]
In a few days the Leonid maximum is expected. Appended is another
model prediction by Peter Brown of UWO, London, Canada, which
I thought is of general interest for all meteor observers.
Good luck with all observing projects!
Juergen Rendtel
IMO President
--------------
1998 Leonid Model Prediction
By Peter Brown, UWO Meteor Group.
Issued November 5th, 1998.
Using a total of 12 different models for the ejection of
meteoroids
from comet Tempel-Tuttle, a preliminary "best"
guestimate for the
location of the strongest peak in activity and its associated ZHR
for the 1998 Leonids has been found.
The 12 model approach involves using three major variations in
meteoroid density (0.1, 0.8 and 4.0 g/cm^3 for bulk density of
the
meteoroid). For each of these three densities, four different
variations in the initial ejection velocities are also employed -
one follows the distributed production model of Crifo which
produces
broad distributions in initial ejection velocity which has a mean
velocity lower than the classical Whipple/Jones ejection model.
In
addition to Crifos distributed production model, a Whipple/Jones
ejection velocity model is used, as well as a second variant of
the
same with a heliocentric velocity dependance of r^-0.5 in place
of
the usual r^-1. The fourth model is again a variant on the
Jones/Whipple model in which the ejection velocity at a given
heliocentric distance is not single-valued in the monte carlo
generating routine, but rather has a parabolic distribution of
probable velocities about the average Jones/Whipple velocity for
the
chosen heliocentric distance. See Brown and Jones (1998), Icarus,
v.
133, pp. 36 - 68 for more details.
The results of the modelling for the Leonids, using ejections at
all
perhelion passages of the comet back to 1499 AD (ie 15
revolutions of the comet prior to the current epoch). A simple
summation of the meteoroids which are then visible at Earth at
the
present time from this ensemble and which would produce visually
observable meteors (mass > 1 mg) was then computed from all
ejecta.
A meteoroid is defined as being Earth-intersecting if its nodal
radius is within 0.005 AU of Earth at the longitude of its
descending node. All models suggested a steep increase in
activity
beginning in December, 1997/early 1998 accompanying the passage
of
Tempel-Tuttle. The resolution of the modelling is of order 2
months
and thus all models suggest that this November will show
significantly increased activity relative to 1997 (when the peak
ZHR
reached just short of 100), and likely activity approaching
meteor
storm levels (ZHRs of order 1000). Using 1997 as a baseline and
taking the peak ZHR to have been 96 +/- 13 at 235.22 +/- 0.02
(J2000) in 1997 we have extrapolated the relative model
difference
between the activity strength predicted by the model in 1997 to
that
observed and that predicted for 1998. Using a mean of all
models,
produces a predicted location for the peak in 1998 of 235.26 +/-
0.04 (J2000) with a peak ZHR of 1200 +/- 280. This solar
longitude
corresponds to Nov 17 at 19:20 UT with a 1-sigma uncertainty of
60
minutes. We emphasize that due to the model results sensitive
dependance on density of the meteoroids, the range of possible
ZHRs
extends from slightly lower than the bound given above to nearly
10
000 (the higher values associated with the models using the least
dense meteoroids and lowest ejection velocities).
The use of relative modelling difference between 1997 and 1998
implies that the veracity of the prediction in 1998 relies
entirely
on the accuracy of the magniude of the ZHR reported in 1997 under
full moon conditions. As well as the above, the models suggest
that
broad activity, persisting for of order a full day centred about
this peak should be noticeably above normal Leonid background
levels
and should be rich in larger meteoroids in 1998 most notably
after
the time of the peak. The model suggests ZHRs of order 100 or
greater in the 3-4 hour window prior to the peak and ZHRs of
order
100-200 persisting for many hours after the peak.
The mass index near the time of the peak over the visual
magnitude
range will be near 1.6 +/- 0.1. It is worth noting that a
significant decrease in the mass index from 1.8 +- 0.1 several
hours
prior to the peak to this lower value and then upward again after
the peak is visible in most models.
Peter Brown
Meteor Physics Lab
Department of Physics and Astronomy
University of Western Ontario
London, Ontario
N6A 3K7
Canada
Voice:1-519-679-2111 x6458
Fax:1-519-661-2033
==============
(7) SEARCHING FOR ANSWERS TO SOLAR MYSTERIES
From NASA Science News <expressnews@sslab.msfc.nasa.gov>
Nov 5: A Tale of Two Mysteries on shuttle Discovery - What do the
Little Ice Age and the solar corona have in common? They were
both the
target of science experiments on shuttle Discovery earlier this
week.
Full story:
http://science.nasa.gov/newhome/headlines/ast05nov98_1.htm
-----------------
A Tale of Two Mysteries
Solar physics experiments on STS-95 will address two of the
biggest
puzzles of science
November 5, 1998: Shuttle Discovery is carrying two telescopes,
SOLCON
and SPARTAN, designed to unravel two of the most perplexing
mysteries
in science. One mystery concerns the temperature of the Earth:
Did the
Sun cause a "Little Ice Age" two hundred years ago? A
second conundrum
involves the temperature of the Sun: Why is the solar corona, the
outermost layer of the sun's atmosphere, 2,000 times hotter than
the
sun's surface? The STS-95 mission may not solve these
longstanding
puzzles, but scientists hope to uncover some important clues.
Mystery the First: the Solar Constant
In the late 17th century there was a 70 year period called the
Maunder
Minimum when no sunspots were observed on the Sun. The normal
11-yr
sunspot cycle essentially stopped, and solar activity was
abnormally
low. At the same time Northern Europe experienced the
"Little Ice
Age", a series of bitter winters lasting 50 years. There was
another
decrease in sunspot activity between 1800 and 1830. It wasn't as
severe as the Maunder Minimum, but temperatures in Europe and
America
took another dip. The year 1816 is sometimes referred to as
"The Year
without a Summer" because of unusually cold weather. Many of
the
novels of Charles Dickens, which depict harsh winters in London,
were
set in this period.
Today, scientists are wondering if there is a connection. Does
solar
activity influence Earth's climate, and just how constant is the
sun,
anyway? Today the sun deposits 1370 Watts of power on every
square
meter of the Earth's upper atmosphere. That number is called the
solar
constant. Since the early 1980's orbiting spacecraft have been
keeping
an eye on the Sun to monitor possible changes the solar constant.
The
Solar Maximum Mission, which flew from 1980 until 1989
established
that the sun's radiance does fluctuate by a small amount.
"It [the
solar radiance] is 0.1% less during the sunspot minimum than
during
solar maximum", according to Dr. David Hathaway, a solar
physicist at
the NASA MSFC Space Sciences Lab. "These small changes are
probably
not enough to affect climate here on Earth, but what we really
want to
know is this: are there larger changes that take place on time
scales
of 100 years or more? If there are, then there could be a
connection
between the Sun and the Little Ice Age. Right now we just don't
know."
An instrument called SOLCON has been sent aloft on STS-95 to help
answer this question. SOLCON is a radiometer, a device used to
measure
the total power radiated by the sun at all wavelengths. Its
measurements will be used to calibrate instruments on satellites
that
are continuously monitoring the sun's output. "One problem
with
instruments in orbit is that they tend to be good at measuring
small
changes in the solar radiance, but not so good at measuring its
absolute value," continued Hathaway. "Calibration is
very
important."
Mystery the Second: the Solar Corona
The SPARTAN solar observatory was captured and returned to its
berth
yesterday after successfully completing a two-day solar science
mission. About 30 percent of the science data has already been
transmitted to the ground and the remainder will be off-loaded at
landing. SPARTAN Scientist Dr. Richard Fisher noted that
investigators
were pleased to have the satellite in orbit near a solar maximum
cycle
and that its instruments had captured sought-after data on a
solar
mass ejection event.
The main target of SPARTAN's observations was the solar corona.
Astronomers believe something odd is happening there. Here on
Earth as
you move from sea level to higher altitude the air generally
becomes
colder, but the Sun works in reverse. Its outermost layer, the
corona,
is hotter than 1,000,000 degrees C while the visible surface, or
photosphere, has a temperature of only about 6,000 degrees C. How
the
corona is heated is one of the great mysteries of solar physics.
"It should be possible to heat the corona with waves,"
says Dr. John
Davis at the NASA/MSFC Space Sciences Lab. "All kinds of
waves are
generated in the photosphere - such as acoustic waves, from
mechanical
motions, or Alfven waves, from shaking magnetic fields. These
waves
spread upward into the corona which absorbs energy from the
waves.
"The trouble with this idea is that none of the waves likes
to be
absorbed by the corona. They either go right through, or are
reflected
back to their starting point. This is a long-standing problem and
nobody has a good solution for it.
Alternatively, scientists from Marshall have suggested that
energy is
pumped into the corona through a series of little explosive
effects -
microflares - that occur all over the place."
There are lots of theories, but no one knows the answer. The
corona is
hard to study from Earth because its light is relatively dim
compared
to the blindingly bright disk of the sun. The white light corona
can
be viewed from Earth only during a solar eclipse or with a
special
instrument called a coronagraph. Ground-based astronomers are
never
able to see the corona's ultraviolet radiation because Earth's
atmosphere blocks UV rays.
SPARTAN is equipped with two telescopes that can measure both
white
light and UV emissions from the sun's corona.
The white light coronagraph, developed by the High-Altitude
Observatory in Boulder, Colo., will measure the density of the
electrons in the coronal white light. The ultraviolet coronal
spectrometer from the Smithsonian Astrophysical Observatory at
Harvard
will measure the velocities, temperatures, and densities of the
coronal gases.
By comparing the data collected by the two telescopes and
combining
the observations of the SPARTAN 201 missions and Ulysses and
observations made by ground-based instruments, scientists expect
to
gain a much more complete picture of the solar corona and some
insight
into what might be heating it.
SPARTAN 201-05 observations this week were coordinated with
observations made from the Solar and Heliospheric Observatory
(SOHO)
satellite. The second and third missions were coordinated with
the
passage of the Ulysses spacecraft over the sun's south and north
poles.
==================
(8) THE EVOLUTION OF THE HUMAN BRAIN: IS BIGGER BETTER?
M. Henneberg: Evolution of the human brain: Is bigger better?
CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, 1998,
Vol.25,
No.9, pp.745-749
UNIVERSITY OF ADELAIDE, DEPT ANAT SCI, WOOD JONES CHAIR ANTHROPOL
&
COMPARAT ANAT, ADELAIDE, SA 5005, AUSTRALIA
The hominid brain has increased approximately three times in size
since the Pliocene, but so has the brain of equids. The tripling
of
hominid brain size has been considered as an indicator of
increased
mental abilities, as it coincided with the production of tools,
weapons and other artefacts of increasing sophistication. No
indicators of the increase in equid intelligence are known,
Intraspecific correlation between brain size and variously
measured
'intelligence' is, in modern humans, very weak if not completely
absent. With the exception of size, there are no major
differences
between the anatomy of ape and human brains. 2. A study of 297
estimates of body height, 626 estimates of bodyweight and 276
estimates of the cranial capacity of hominids dated at various
periods over the past 5 million years shows that the increase in
hominid brain size was paralleled by an increase in body size.
3. In a sample of 45 variously dated fossil hominids, brain
size correlates isometrically with body size. 4. Since the Late
Pleistocene (approximately 30000 years ago), human brain size
decreased by approximately 10%; yet again, this decrease was
paralleled hy a decrease in body size. 5. Therefore, it may be
concluded that the gross anatomy of the hominid brain is not
related
to its functional capabilities. The large human brain:body size
ratio may be a result of the structural reduction of the size of
the
gastrointestinal tract and, consequently, its musculoskeletal
supports. It is related to richer, meat-based diets and
extra-oral
food processing rather than the exceptional increase in the size
of
the cerebrum. The exceptional mental abilities of humans may be a
result of functional rather than anatomical evolution. Copyright
1998, Institute for Scientific Information Inc.
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