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PostPosted: Mon Aug 07, 2006 10:38 am 
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The SOCIETY for POPULAR ASTRONOMY
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Electronic News Bulletin No. 202 2006 August 6
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Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is Britain's liveliest astronomical society, with
members all over the world. We accept subscription payments online
using our secure site and can take credit and debit cards. You can
join or renew via a secure server or just see how much we have to
offer by visiting http://popastro.c.topica.com/maae2PyabsrAwcixLLVb/


MID-JULY FIREBALLS - FURTHER DETAILS
By Alastair McBeath, SPA Meteor Section Director

Five observers or groups have now reported spotting the ~20:47 UT
fireball on July 14-15, mentioned last time. Only a marginal refinement
to the possible trajectory has been practical so far, with the roughly
east to west track over Oxfordshire-Gloucestershire maybe extending
to South Wales.

Many more fresh details have arrived on the July 18-19 event,
however. Due to a mix up in the early sightings, the time was
incorrectly given previously, and should have been within two minutes
or so of 22:54 UT, not about an hour later as stated in ENB 201. Ten
observations from SE England have been received on it, but it was
seen by many more people across much of Belgium and the
Netherlands too. Preliminary notes from the Continental sightings,
including a provisional projected surface track, have been produced by
the Mira Public Observatory in Grimbergen, Belgium. These suggested
the object flew on a SSE to NNW trending trajectory, passing over
parts of NE France and NW Belgium, starting about 50-60 km SW
of Cambrai in France, and ending perhaps 60-70 km offshore of
Felixstowe on the Suffolk coast of England. The fireball had a very
long atmospheric path, maybe ~260 km. The Mira reports (in Dutch,
but including maps) can be seen at:
http://popastro.c.topica.com/maae2PyabsrAxcixLLVb/ . One of
the European Fireball Network stations, EN97 at Oostkapelle, run
by Klaas Jobse, was lucky in catching the fireball with an all-sky
camera system. The spectacularly long trail can be viewed from the link
at: http://popastro.c.topica.com/maae2PyabsrAycixLLVb/ . Grateful thanks
are due to David Entwistle
for forwarding links regarding the Continental reports especially, and
also some of the UK ones.

More sightings to help refine the UK end of the trajectory further would
be especially welcomed. Details of what information to send and where
to can be found via the Section's "Fireball Observing" page at:
http://popastro.c.topica.com/maae2PyabsrAzcixLLVb/ .


PERSEIDS 2006
By Alastair McBeath, SPA Meteor Section Director

Next weekend brings the annual Perseid maximum. Excellent news is
that it is perfectly timed for UK observations this year, and happens on
a Saturday night to Sunday morning. It is due between 23h00m-
01h30m UT on August 12-13, with the shower's radiant nicely on-
view before that earlier time, improving all night after then.
Theoretical
calculations made some years ago suggested Perseid activity might be
somewhat enhanced this year, though probably less strongly than in
2004, when a brief primary maximum with Zenithal Hourly Rates
(ZHRs) of 200+ was seen a few hours before the usual one (initial
notes were in ENB 156). There is no guarantee this will happen, and its
timing is not certain, but it may occur at some time on August 12 or 13,
perhaps not far from the predicted "normal" peak range above, either
before or afterwards.

The bad news is the waning gibbous Moon will rise before 21h UT for
the whole UK on August 12-13, in Pisces, so like the Perseid radiant,
it will be nicely visible throughout the night too! While causing
problems
for visual watchers, Perseid activity should still be well worth seeing
that night, or maybe for a couple of nights before and a night
afterwards, judging by recent past returns, when ZHRs of these swift,
often bright, and commonly trained meteors should be around 40-100
or so. Rates will probably be highest, and thus easier to detect, only
on
August 12-13 though. For best results, watch as much clear sky as
you comfortably can, not looking too near the Perseid radiant, and
avoid having the Moon near your field of view - perhaps towards
UMa and UMi, even round to Boo-Her, for Britain.

More details on the Perseids, including a radiant chart, and others of
August's meteor showers can be found at:
http://popastro.c.topica.com/maae2PyabsrAAcixLLVb/ .

Good luck, clear skies, and please let me know how you get on!


POSSIBLE METEORITE FALL, WESTERN INDIA
By Alastair McBeath, SPA Meteor Section Director

Brief media reports suggest a major fragmenting fireball shot over parts
of Western India around 16:15 UT on July 31, creating sonic booms
that shook houses and the ground. Details are still unclear, but there
have been suggestions meteorites may have landed in the Kutch region
of western Gujarat. Numerous sightings were reported particularly from
the Kathiawar Peninsula, also in Gujarat, notably from Jamnagar and
Rajkot. The reports can be read at:
http://popastro.c.topica.com/maae2PyabsrABcixLLVb/ and:
http://popastro.c.topica.com/maae2PyabsrACcixLLVb/


PLANS FOR GIANT TELESCOPES
New Scientist

A giant telescope with a mirror up to 60 metres in diameter is being
planned by the European Southern Observatory. The telescope might be
able to detect Earth-like planets (if they exist) around other stars,
and detect the Universe's first galaxies. ESO had previously been
considering a 100-metre telescope called the OverWhelmingly Large
telescope (OWL) but a review of the concept concluded that the project
would be too risky and would take too long to build. The goal now is
to build a 60-m one for $950M and have it ready for use by 2015.

Two other groups are also pushing forward with plans for giant
telescopes. A US-Australian consortium is planning a 24.5-metre
instrument called the Giant Magellan Telescope (GMT) to be built by
2016 and a US-Canadian group is planning the Thirty-Metre Telescope
(TMT), also to be built by 2016. The giant ground-based telescopes
that are planned would have four or more times the aperture, and so in
principle four or more times the resolution, of the James Webb Space
Telescope (JWST) that is proposed to replace Hubble.


UKIRT INFRARED DEEP-SKY SURVEY
Science Daily

British astronomers are making available the first data from the
largest and most sensitive survey of the heavens in infrared light.
The UKIRT Infrared Deep Sky Survey (UKIDSS) has completed the first of
seven years of data collection, studying objects that are too faint to
see at visible wavelengths, such as very distant or very cool objects.
New data on young galaxies are already challenging current thinking on
galaxy formation, revealing galaxies that are massive at a much
earlier stage of development than expected. The first scientific
results already indicate how useful the full survey may be at finding
rare objects that may hold clues to how stars and galaxies in our
Universe formed. UKIDSS will make an atlas of large areas of the sky
in the deep infrared which will reveal more cool and faint objects
than have been seen before as well as objects at extreme distances.

So far several hundred thousand galaxies have been detected; among
them are nine that appear to be 12 billion light-years away and are
unusual in that they appear to be very massive for their age. Their
existence sits uneasily with the received idea that galaxies form
gradually over billions of years as smaller components merge together.


SPACE DATE SET FOR SCOTTY'S ASHES
BBC Online

Star Trek actor James Doohan, who played the engineer Scotty in the
original TV series, will have his remains blasted into space in
October. The actor's ashes were supposed to be sent into orbit last
year, but the flight was delayed as tests were carried out on the
rocket. Doohan died of Alzheimer's disease and pneumonia in July
2005, aged 85. The actor's ashes will be sent into space along with
the remains of around 100 other people, including astronaut Gordon
Cooper, who first went to space in 1963. They will remain there for
several years, after which they will drop back towards Earth, burning
up on re-entry.


POSSIBLE LAKES ON TITAN
The Register

New radar maps of Titan appear to show that it has surface lakes
dotted around its north pole. No Solar-System object other than the
Earth has previously been shown to have standing bodies of liquid on
its surface. Titan's lakes would almost certainly be some kind of
hydrocarbon -- most likely methane or ethane. The radar maps show
dark patches with channels leading into and out of them. Some of the
patches are completely black to radar, indicating that they are
extremely smooth. Others have rims around the edges, suggesting that
liquid has been evaporating and leaving a deposit behind. Scientists
have speculated for some time that liquid methane might exist in
Titan's colder polar regions. If there are bodies of liquid, that
should become clear as time goes on because they could be expected to
change -- becoming smaller or larger, or even rougher as winds create
waves on their surfaces.


HIDDEN BLACK HOLES ELUDE ASTRONOMERS
The Register

Cynics claim to have noticed that the less that is known about a thing
the more difficulties are readily explained by it. Supermassive black
holes are a case in point -- they have been used to explain all sorts
of things, and in particular the Universe's background X-ray
radiation, but it would take a lot more than have actually been
thought to have been identified to make their explanation of that
radiation plausible. So their supporters claim that the 'missing'
black holes are hiding behind huge clouds of dust capable of absorbing
all but the highest-energy X-ray radiation, and that once the X-rays
emerge from behind the shrouds of dust they combine to form the high-
energy peaks in the radiation that permeates the Universe. However,
researchers working on a high-energy census of the sky have not been
able to find enough of even the hidden black holes to account for all
the observed radiation. Indeed, even 'Integral', the satellite
dedicated to GRBs, has been able to suggest that the proportion of
hidden black holes may be only 10--15%. The apologists have been
driven to fall back on the rather hollow hypotheses that the hidden
black holes that they would like to be responsible for the observed
energy are hidden further away than has been supposed, or even that
they are just more hidden than astronomers realised and are below the
detection capabilities even of Integral.


UNIVERSE'S LARGEST STRUCTURE?
Subaru Telescope, National Astronomical Observatory of Japan

Astronomers who were using the Subaru telescope on Mauna Kea to study
a region 12 billion light-years away that is known to have a large
concentration of galaxies found the concentration to be just a portion
of a much larger structure. The structure extends over 200 million
light years and its population of galaxies is up to four times
denser than the Universe's average. It is also studded with more than
30 large concentrations of gas, each up to ten times as massive as our
own galaxy. The gas clouds are probably similar to the progenitors of
the most massive galaxies that exist today. The structure as a whole,
and others like it, may be similar to the precursors of the largest
structures we see today which contain multiple clusters of galaxies.


SURVEY YIELDS APPARENT CONUNDRUM BUT IS SILENT ON THE OBVIOUS ANSWER
Physics.Org

A survey of galaxies observed along the sight-lines to quasars and to
the sources of gamma-ray bursts (GRBs) -- both extremely luminous,
distant objects -- has run into an apparent inconsistency. Galaxies
appear to be four times more common in the directions of GRBs than in
the directions of quasars. The study is based on a straightforward
concept: when light from a GRB or a quasar passes through a foreground
galaxy on its way to us, the absorption of certain wavelengths of
light by gas associated with the galaxy creates a characteristic
signature in the spectrum of light from the distant object. That
provides a marker for the presence of a galaxy in front of the object,
even if the galaxy itself is too faint to observe directly, but there
is no reason to expect galaxies in the foreground to have any
relationship to the background light sources. 15 GRBs were observed
by 'SWIFT' in the new study, and strong absorption signatures
indicating the presence of galaxies were found along 14 of the
sight-lines. Previously, data from the Sloan Sky Survey to determine
the incidence of galaxies along the sight-lines to quasars would have
predicted the detection of only 3.8 galaxies instead of the 14
detected along the GRB sightlines. The obvious answer, that GRBs are
on average a lot more distant than quasars, so there is a lot more
room for galaxies between them and us, seems either to have escaped
the researchers or else has not commended itself to them.


PEROXIDE SNOW ON MARS?
University of California at Berkeley

Certain students of the Martian atmosphere have recently argued that
oxidizing chemicals could be produced by static electricity
generated in the planet-wide dust storms that sometimes obscure the
surface for months. If such chemicals have been produced regularly
over the last 3 billion years, when Mars has presumably been dry and
dusty, the accumulated peroxide in the surface soil could have built
up to levels that would kill 'life as we know it'. All in all, it
seems that the intense ultraviolet exposure, the low temperatures, the
lack of water and the oxidants in the soil would make it difficult for
even a microbe to survive on Mars. It is further suggested that the
oxidants could reach such concentrations near the ground during a
storm that they would condense into falling snow, contaminating the
top layers of soil. The superoxidants not only could destroy organic
material on Mars, but accelerate the loss of methane from the
atmosphere.



NEXT BULLETIN

Owing to holidays, the next scheduled bulletin will be not be issued
until September 3.


(c) 2006 the Society for Popular Astronomy


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