WADHURST ASTRONOMICAL SOCIETY
NOVEMBER NEWSLETTER 2006
INDEX: MEETINGS, OTHER NEWS, CONTACTS
given to the October meeting by Jerry Workman
was a return visit by Jerry Workman who is the chairman the Loughton
Astronomical Society in Essex. His
talk this time was to update us on recent United States Mars missions, beginning
with a picture taken by an orbiting satellite of the landing sites of Vikings 1
and 2. Viking 1 was launched in August 1975, reaching Mars in June 1976. The orbiter had shown that there was quite a bit of
difference between the northern and southern hemispheres of Mars.
The northern hemisphere was much smoother.
The first landing site was chosen to be flat and fairly free of rocks and
the actual site was on the western edge of Chryse Planitia in the northern
equatorial region of the planet.
a successful landing by Viking 1, the first photographs showed a few surface
rocks but the colours had to be adjusted by using the sky as reference white.
The most useful pictures taken were black and white, but in colour the
rocks now looked orange, although one near-by rock had some green marks on it
that might have been moss but turned out to be surface minerals.
was evidence in the thin atmosphere of very high winds and many of the rocks
showed dust erosion. There were
also signs that water had once caused certain features that could have been
caused a considerable time ago.
2 was launched 7 weeks after Viking 1 and also landed safely but this time the
site selected was just a few metres from Mie Crater on Utopia Planitia with the
aim of looking at a different kind of Mars rock where there was the possibility
of observing rock that had been thrown up from beneath the surface.
Viking 1 nor Viking 2 could find any evidence of life on the planet despite the
suggestion of the presence of water.
went on to say that in July 1997 Mars Pathfinder landed on the surface also near
Chryse Planitia. This site is now
known as the Carl Sagan Memorial Station. The
Mars rover, Sojourner, began to examine the atmosphere, soil and rocks.
Findings from the investigations showed that the planet had once been
warmer and water in its liquid form had flowed beneath a thicker atmosphere,
much of which had been lost to outer space.
rocks had been given names because of their appearance, Barnacle Bill and
another called Yogi Bear, both quite close to the landing site.
Both showed evidence of wind erosion by sand blasting.
Small holes in their surfaces are thought to have been caused by gas
trapped in pockets inside the rock then bursting out as erosion had taken place.
Erosion had also been caused by the incredible changes in temperature
from -60 degrees Celsius to -5 degrees. The
soil was found to be rich in iron and to be very magnetic.
Jerry came to the last two rovers to have landed on the surface of Mars and
which are still working today although they have long passed their expected
working life. Spirit landed close to Gusev Crater in January 2004.
This crater was selected because previous satellite pictures had shown
what looked like a channel leading out of the crater and could have been caused
by water pouring out from the crater some time in the past.
This landing site was named Columbia Memorial Station in memory of the
seven astronauts who had lost their lives in the Columbia shuttle disaster of
a panoramic picture, a group of seven hills could be seen to the east.
Each of these hills was named after one of the seven astronauts.
to where Spirit landed was a shallow depression called "Sleepy Hollow"
where a brush tool was used to enable rocks to be drilled and penetrated to more
easily analyse the material using a spectrometer.
The rocks were found to be composed mainly of olivine, with magnetite,
ferrous and pyroxene.
then moved further afield to bypass Bonneville Crater, regarded as too great a
risk to enter, making for the Columbia Hills.
Jerry showed a number of slides of interesting rocks on the way, most
showed signs of erosion due to sand blasting and considerable changes in
temperature during the Martian day. Some
of the rocks were soft and had eroded more easily than others resulting in some
very odd shaped rocks. Some of
Jerry's slides were of remarkable microphotographs showing close-up details of
decided that Spirit rover should attempt to climb 300 feet high Husband Hill by
taking a zigzag path to the summit. This
was 2 kilometres from the landing site and at present Spirit rover is descending
the far side of the hill, sending data via the Orbiter back to Earth. Jerry said that the data return path at present is about
forty minutes between Mars and Earth, meaning that great care is needed to
direct the rover safely.
weeks after Spirit landed, Opportunity rover landed on the other side of the
planet to look at a totally different rock formation.
many of the rocks were small rounded dark pebbles of higher density than in
other nearby material. Jerry
thought these were released from the bigger rocks during erosion where the rest
of the rock had been removed leaving the surface scattered with these 1
centimetre diameter pebbles composed of Hematite.
day on Mars (only slightly longer than an Earth day) is called a Sol.
Both rovers were designed to last about 90 Sols but Opportunity has so
far lasted over 900 Sols and has reached the rim of Victoria crater having
passed the Lander's discarded heat shield and also discovering what is thought
to be a meteorite from outer space.
concluded by talking about Phoenix, which is a mission, due to be launched in
August 2007 and arriving at Mars on the 18th of May 2008.
Phoenix is to research the poles of Mars with the intention of looking
for water trapped in the rocks or in the shadow of the rocks.
was very a informative talk and we look forward to his return visit in April
when he brings us up to date with the Mars Express Mission.
Wednesday 15th November 2006. David Rooney, who is the Deputy Horologist at Greenwich Museum, is to give us a talk called "A Brief History of GMT". The new Time Galleries opened last February as part of the improvements to the Museum.
usual, the meeting will be held in the Upper Room of the Methodist Church, the
High Street, Wadhurst, opposite Uplands College.
The meeting commences at 1930.
13th December 2006. Note that
this will be second Wednesday of the month.
Phil Berry, a member of the Society is giving a talk he calls "The
Trials and Tribulations of an Amateur Astronomer", which should bring to
mind some interesting experiences of our own.
this is our last meeting before Christmas Phil's talk will be followed by mince
pies and beverages!
17th January 2007 The talk is
given by Bob Seaney, one of our Society members and the title of his talk is
"The Astronomical Art of Chesley Bonestell - Destination Moon (1953)
will be followed by the Society's Annual General Meeting, which takes place in
January for the first time.
21st February 2007 Ian King
presents a talk he calls "The GranTeCan" which might have something to
do with a trip he took recently.
Wednesday 21 March 2007 Our guest speaker will be Dr. Stephen Serjeant and his talk is called "The Big Questions in Cosmology".
Our speakers are arranged by Phil Berry, and I think you will agree, he is finding some excellent talks. It would be also be very interesting to hear from any member who would like to give a talk. It would not have to be for the whole meeting but very often members mention interesting experiences, which could be the basis of a talk. The Society needs more talks that reflect the amateur's problems, and how they have been resolved, - or not resolved for that matter. It would also help Phil if you could contact him with suggestions.
GO TO INDEX
events take place his month. In the
past few years the Leonid Meteor shower has been quite spectacular and it is
thought this might be the last outburst of strong activity for the time being as
the Earth passes close to the centre of the debris remaining from comet 55P/Tempel-Tuttle
whose parent comet passed the Earth in 1932.
It is estimated that strong outbursts occur only every 33 years.
The peak is at 0445 on the morning of the 18th November.
The meteors are very fast, bright and often leave lingering ionisation
trains. The general shower can be
observed between the 15th and 20th of November originating close to Regulus in
the constellation of Leo.
is close to the Sun at the start of the month and in fact transits the disk of
the Sun viewed from the Pacific Ocean and parts of Australia on the 8th of
November but we do get a chance to see Mercury just before Sun-rise when is
rises at 0530 on the 25th November. It
will have a magnitude of -0.4 with a phase of 60 %.
The Sun rises at 0730 so viewing should be safe before that. This will be about the best view we will have had this year.
is still in a favourable position to observe, rising just before midnight at the
beginning of the month and rising at about 2200 by the end of November.
It will have a magnitude of +0.4 and is about 5 degrees east of Regulus
in the constellation of Leo.
NASA SPACE PLACE
Planet in the Machine
Diane K. Fisher and Tony Phillips
story goes that a butterfly flapping its wings in Brazil can, over time, cause a
tornado in Kansas. The "butterfly effect" is a common term to evoke
the complexity of interdependent variables affecting weather around the globe.
It alludes to the notion that small changes in initial conditions can
cause wildly varying outcomes.
imagine millions of butterflies flapping their wings.
And flies and crickets and birds. Now
you understand why weather is so complex.
kidding aside, insects are not in control.
The real "butterfly effect" is driven by, for example, global
winds and ocean currents, polar ice (melting and freezing), clouds and rain, and
blowing desert dust. All these
things interact with one another in bewilderingly complicated ways.
then there's the human race. If a butterfly can cause a tornado, what can humans
cause with their boundlessly reckless disturbances of initial conditions?
how it all fits together is a relatively new field called Earth system science.
Earth system scientists work on building and fine-tuning mathematical models
(computer programs) that describe the complex inter-relationships of Earth's
carbon, water, energy, and trace gases as they are exchanged between the
terrestrial biosphere and the atmosphere. Ultimately,
they hope to understand Earth as an integrated system, and model changes in
climate over the next 50-100 years. The better the models, the more accurate and detailed will be
the image in the crystal ball.
Earth System Science program provides real-world data for these models via a
swarm of Earth-observing satellites. The
satellites, which go by names like Terra and Aqua, keep an eye on Earth's land,
biosphere, atmosphere, clouds, ice, and oceans.
The data they collect are crucial to the modelling efforts.
models aim to predict short-term effects-in other words, weather.
They may become part of severe weather warning systems and actually save
lives. Other models aim to predict long-term effects-or climate.
But, long-term predictions are much more difficult and much less likely
to be believed by the general population, since only time can actually prove or
disprove their validity. After all,
small errors become large errors as the model is left to run into the future.
However, as the models are further validated with near - and longer-term
data, and as different models converge on a common scenario, they become more
and more trustworthy to show us the future while we can still do something about
a listing and more information on each of NASA's (and their partners') Earth
data-gathering missions, visit science.hq.nasa.gov/missions/earth.html.
Kids can get an easy introduction to Earth system science and play Earthy
word games at spaceplace.nasa.gov/en/kids/earth/wordfind
This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.
GO TO INDEX
Tim Bance 01732 832745
Phil Berry 01892 783544 email@example.com
Mike Wyles 01892 542863
Website Michael Harte 01892 783292
Newsletter Editor Geoff Rathbone
Any material for inclusion in the December Newsletter should be with the Editor by November 28th 2006
GO TO INDEX