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Monday, 30 September 2013

SPA ENB No. 361

                   The SOCIETY for POPULAR ASTRONOMY

          Electronic News Bulletin No. 361   2013 September 29

Here is the latest round-up of news from the Society for Popular
Astronomy.  We like to think that the SPA is Britain's liveliest
astronomical society; it has members all over the world.  We accept
subscription payments online at 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


Most meteor showers occur when the Earth ploughs through streams of
debris released from comets in the inner Solar System.  The Geminids,
which grace the night sky annually in December, are one of the best
known and most spectacular of the dozens of meteor showers.  However,
astronomers have known for 30 years that the Geminids are not caused
by a comet but by a Sun-grazing 5-km-diameter asteroid called (3200)
Phaethon.  Phaethon has now been found to show a comet-like tail of
dust particles blown backwards by radiation pressure from the Sun.
The tail, however, does not arise like a comet's, through the
vaporization of an icy nucleus.  Researchers believe that, during its
close approach to the Sun, Phaethon becomes so hot that rocks on the
surface crack and crumble to dust under the extreme heat.

Until recently astronomers had never caught Phaethon in the actual act
of throwing out particles.  In 2010. however, astronomers Jewitt and
Jing Li found Phaethon to be anomalously bright when closest to the
Sun.  The key to their success was their use of the STEREO Sun-
observing spacecraft.  Phaethon at perihelion appears only 8° from the
Sun, making observations with normal telescopes impossible.  Now, in
further STEREO observations from 2009 and 2012, astronomers have
observed a comet-like tail extending from Phaethon.  The tail gives
incontrovertible evidence that Phaethon ejects dust but that still
does not tell us why.  Comets do it because they contain ice that
vaporizes in the heat of the Sun, creating a wind that blows embedded
dust particles from the nucleus.  Phaethon's closest approach to the
Sun is just 14 per cent of the average Earth-Sun distance, i.e. 0.14
Astronomical Unit (AU).  That is the closest perhelion distance of
any named asteroid, and implies that Phaethon must reach temperatures
over 700°C -- far too hot for ice to survive.

The astronomers believe that thermal fractures and desiccation
fractures (like mud cracks in a dry lake bed) may be launching small
dust particles that are then picked up by sunlight and pushed into the
tail.  While this is the first time that thermal disintegration has
been found to play an important role in the Solar System, astronomers
have already detected around some 'nearby' stars unexpected amounts of
hot dust that might have been similarly-produced.  So, is Phaethon an
asteroid or a comet?  Asteroids and comets tend to occupy entirely
different regions of the Solar System; asteroids between Mars and
Jupiter (roughly 2 to 3.5 AU) and comets om the frigid trans-Neptunian
realms (30 AU and beyond).  According to the nature of its orbit,
Phaethon is definitely an asteroid.  But by ejecting dust it behaves
like a 'rock comet'.


'Solar twins', stars that are very similar to our Sun in mass,
temperature and chemical abundances, are rare.  Very few have been
found since the first one was discovered in 1997.  Now it has been
asserted, on the basis of spectra taken with the VLT in Chile, that
the ninth-magnitude star HD 197027, 250 light-years away in
Capricornus, is more like the Sun than any other solar twin.  The
astronomers found HD 197027 to be the oldest solar twin known to date;
it is estimated to be 8.2 billion years old, compared to 4.6 billion
years for our own Sun.  [Evidently 'twin' is a gross misnomer, then --
ED.]  Observations suggest that HD 197027 may have rocky 'terrestrial'
planets.  Studies of the star may offer a forecast of what may happen
to our own Sun when it reaches that age, and they have already
contributed one suggestion, concerning why does the Sun have such a
strangely low lithium content?  Lithium, the third element in the
Periodic Table, was created in the Big Bang along with hydrogen and
helium.  Astronomers have wondered why some stars appear to have less
lithium than others.  With the new observations of HD 197027, they
appear to have taken a step towards solving that problem by finding a
correlation between a Sun-like star's age and its lithium content.

Harvard-Smithsonian Center for Astrophysics.

Some astronomers are interested in hunting for ever-colder star-like
bodies, and two years ago a new class of objects was discovered by
researchers with the WISE space telescope.  However, until now nobody
has known exactly how cool their surfaces really are -- some evidence
suggested they could be at room temperature.  A new study shows that
while those brown dwarfs are indeed the coolest known star-like
bodies, they are warmer than previously thought, with temperatures
about 120-180°C.  To reach such low surface temperatures after cooling
for billions of years means that the objects can have only about 5 to
20 times the mass of Jupiter.  Their only source of energy is from
their own gravitational contraction, which depends directly on their
mass.  If such an object were found orbiting a star, there is a good
chance that it would be called a planet, but because they probably
formed on their own and not in proto-planetary discs, astronomers call
the objects brown dwarfs even though they are of 'planetary mass'.
Characterizing them is difficult because they emit most of their light
at infrared wavelengths, and they are very faint owing to their small
size and low temperature.  To get accurate temperatures, it is
necessary to know their distances; from parallaxes obtained with the
Spitzer space telescope, the team found that they are 20 to 50
light-years away.  The observable properties of the objects do not
seem to correlate as strongly with temperature as those of warmer
brown dwarfs and stars.  Perhaps other factors, such as convective
mixing, play increased roles in driving the chemistry at the surface.
The study reported here examined the initial sample of the coldest
brown dwarfs discovered in the WISE survey data.  Additional objects
discovered in the past two years remain to be studied.


Globular clusters, dense groups of hundreds of thousands of stars,
contain some of the oldest surviving stars in the Universe.  Almost
95% of globular-cluster formation occurred within the first one or two
billion years after the Universe was born.  An international team of
astronomers has now used the Hubble telescope to discover an
extraordinary population of globular clusters in the crowded core of
the rich grouping of galaxies Abell 1689.  The team found that the
globular clusters are intimately intertwined with dark matter. The
study of Abell 1689 suggests how the relationship between globular
clusters and dark matter depends on the distance from centre of the
galaxy grouping.  The Hubble study shows that most of the globular
clusters in Abell 1689 formed near the centre of the galaxy cluster,
which contains a deep well of dark matter.  Their number decreases
outwards, and so does the amount of dark matter.  The images showed
the visible-light glow of 10,000 globular clusters, some as dim as
29th magnitude; on the basis of that number, the team estimated that
there might be more than 160,000 globular clusters within a diameter
of 2.4 million light-years.  For comparison, our Milky Way galaxy
has about 150 such clusters.  Hubble can actually see only the
brightest clusters; the majority are estimated to be more like 31st
magnitude, out of reach of Hubble but not of the planned future
James Webb space telescope.


The Voyager 1 spacecraft is now officially the first man-made object
to enter true interstellar space.  The 36-year-old probe is about 19
billion kilometres away.  New data indicate that it has been moving
for about one year through the plasma, or ionized gas, that exists
in the space between stars.  Voyager is in a transitional region
immediately outside the solar bubble, where some effects from the Sun
are still evident.  It first detected the increased pressure of
interstellar space on the heliosphere, the bubble of charged particles
surrounding the Sun that reaches far beyond the outer planets, in
2004.  Scientists then looked for evidence of the spacecraft's
interstellar arrival, knowing that the data analysis and interpret-
ation could take months or years.  Voyager 1 has not got a working
plasma sensor, so the scientists needed a different way to measure
the spacecraft's plasma environment.  A coronal mass ejection, a
massive burst of solar wind and magnetic fields that erupted from the
Sun in 2012 March, provided the data that they needed.  When that blast
from the Sun eventually arrived at Voyager 1's location last April,
the plasma around the spacecraft began to vibrate like air in an organ
pipe.  On April 9, Voyager 1's plasma-wave instrument detected the
movement.  The frequency of the oscillations helped scientists to
estimate the density of the plasma.  The spacecraft was found to be
bathed in plasma more than 40 times denser than it had encountered in
the outer parts of the heliosphere.  Such a density is to be expected
in interstellar space.  The plasma-wave team reviewed its data and
found an earlier, fainter set of oscillations in late 2012.  After
considering both events, the team estimated that Voyager 1 first
reached interstellar space in 2012 August.

Voyager 1 and its twin, Voyager 2, were launched 16 days apart in
1977.  Both spacecraft flew by Jupiter and Saturn.  Voyager 2 also
flew by Uranus and Neptune.  Voyager 2, launched before Voyager 1, is
the spacecraft that has been continuously operating the longest.
Voyager mission controllers still talk to or receive data from both
Voyagers every day, though the emitted signals are very faint, being
emitted a long way away at a power of about 23 watts.  Data from
Voyager 1's instruments are transmitted typically at 160 bits per
second, and received by 34-m and 70-m Deep Space Network stations.
The signal from Voyager 1 takes about 17 hours to reach us.
Scientists do not know when Voyager 1 will reach the undisturbed part
of interstellar space where there is no influence from the Sun, or
when Voyager 2 may cross into interstellar space.


The Jet Propulsion Laboratory has pronounced the mission at an end
after being unable to communicate with the spacecraft since early
August.  Launched in 2005 January, the spacecraft first travelled
about 431 million kilometres to the vicinity of Comet Tempel 1.  On
2005 July 3, the spacecraft deployed an impactor into the path of the
comet, to be run into by its nucleus on July 4.  That caused material
from below the comet's surface to be blasted out into space where it
could be examined by the telescopes and instrumentation of the flyby
spacecraft.  Sixteen days after the encounter, the Deep Impact team
placed the spacecraft on a trajectory to fly back past the Earth in
late 2007 to put it on course to visit another comet, Hartley 2.  The
spacecraft's extended mission culminated in the successful encounter
with the comet on 2010 Nov. 4.  Along the way, it also observed six
different stars to confirm the motion of planets orbiting them, and
took images and data concerning the Earth, the Moon and Mars.  The
data helped to confirm the existence of water on the Moon, and
attempted to confirm the methane signature in the atmosphere of Mars.
In 2012 January, Deep Impact performed imaging and determined the
composition of the distant comet C/2009 P1 (Garradd).  It took images
of comet ISON this year.  After losing contact with the spacecraft
last month, mission controllers spent several weeks trying to uplink
commands to reactivate its onboard systems.  Although the exact cause
of the loss is not known, analysis has uncovered a potential problem
with computer time-tagging that could have led to a loss of control
of Deep Impact's orientation.  That would then affect the positioning
of its radio antennae, making communication difficult, as well as its
solar arrays, which would in turn prevent the spacecraft from getting
power and allow low temperatures to ruin onboard equipment, freezing
its battery and propulsion systems.


After a journey of almost ten years, the Rosetta mission has just a
few months left to cruise before beginning its rendezvous with Comet
67P/Churymov-Gerasimenko, a 'dirty snowball' of ice and dust that
preserves material from the formation of the Solar System.  During
2014, Rosetta will both start to orbit the comet's nucleus and deploy
a small laboratory of scientific instruments, Philae, to land on the
comet's surface.  To aid Rosetta, an international group of scientists
is using ground-based telescopes in an effort to understand the
behaviour of the comet as it approaches the Sun and begins to form its
tail.  Astronomers would like to understand the formation and
evolution of dust coma structures at all scales, from tiny filaments
only visible close to the surface of the nucleus, to large structures
extending tens of thousands of kilometres in the coma.  Comet 67P
appears to behave in a very consistent way, at least over the last two
orbits.  The southern hemisphere is more active than the northern and
there are three major active regions from where there emerge gas jets,
which can eject dust particles at around 50 km/h.

To safeguard the spacecraft during its long, cold journey through deep
space, Rosetta was placed into hibernation in 2011.  Research suggests
that 67P will start emitting gas and dust by next March, two months
after the spacecraft receives its wake-up call on 2014 January 20.
The scientists have based their predictions on 31 sets of images that
enabled them to study changes in brightness and hence the activity
levels of the comet was at different points in its orbit.  They
estimated that the comet would start to form its tail at distance of
around 450 million kilometres from the Sun, when it would become warm
enough for water ice to sublimate.  Instead, it became active much
further out, at 650 million kilometres.  Water will still be frozen
solid at that distance from the Sun, so some other gas must be
responsible for the earlier activity that has been observed.

By Peter Grego, Editor, Popular Astronomy

The September-October issue of Popular Astronomy will be considerably
late in reaching members.  As Editor I take full and sole
responsibility for the delay, and I sincerely apologise to all SPA
members for the delay and for any inconvenience it may cause.  For
those wanting timely information about celestial happenings, the
September-October Sky Diary has been posted on the SPA website and can
be found by clicking the link at

By Geoff Elston, SPA Solar Section Director

There was a slight rise in Mean Daily Frequency, up from 3.39 the
previous month to 4.39 in August, and the Relative Sunspot Number,
51.49 in July, increased to 55.84 in August.  All of the sunspot
groups in August were small but some of them showed considerable
detail.  There were no days when the solar disc was blank.  Faculae
either associated with sunspots or in isolation were seen near the
limb on most days.

The first week of August showed a fairly even spread of small sunspots
across the solar disc.  Active Regions (AR) 1806, 1808 and 1809 were
the most evident by the 3rd.  The level of sunspot activity then
declined very slightly as groups were carried westwards and over the
limb by the Sun's rotation.  From the 11th to the 18th nearly all
sunspots were to the south of the equator.  I would estimate that
around that time, ARs 1817 and 1818 appeared the biggest and most
active of the month.  They were seen to develop as they headed
westwards across the disc.  From about mid-August onwards the Sun was
very spotted, with numerous small spots and pores.  As they moved
westwards the level of sunspot activity started to decline again.
I noticed on the 25th that AR 1835, lying near the eastern limb,
appeared to show the Wilson Effect.  On the 30th, AR 1835, then near
the centre of the disc, showed some intricate detail that had faded
by the last day of the month.

MDF 4.39 R 55.84

In comparison to white light, the Sun in H-alpha was more active, with
a number of bright plages associated with sunspots, dark filaments
and bright prominences making their appearance throughout the month.
I received a few fine drawings and many images of the Sun in H-alpha
for August.  Early August saw a number of mostly small prominences on
the south and southwest limbs.  On the 3rd, AR 1809 showed extensive
plages around it and a coiled filament nearby that persisted over the
following days.  Between 6th and 8th a large dark filament, associated
with a prominence on the SE limb, was seen.  Prominences were again
evident on the 12th along the E limb, and on the S-SE limbs on the
13th, as was a large dark filament on the SW quarter of the solar disc.
By the 16th plages were seen around ARs 1817 and 1818 and several
filaments around ARs 1818 and 1820.  An impressive, broad and long
filament extended from the S limb around that time and persisted until
at least the 25th.  A particularly active prominence appeared on the
22nd along the NW limb, active enough to display change during

MDF 7.24

Go to the Solar Section link on the SPA home page to see a selection of
the many remarkable images and drawings made by the Section membership.

By Karen Barker

We started as a group of Open University students, who were made aware
that the BBC was planning to cancel The Sky At Night.  That is
something to which we strongly object.  Since we started the campaign
to save S@N, the BBC has stated that it is still in discussions about
the future of the programme.

We are also concerned that once (if) the programme is brought back,
its format will have been detrimentally changed.  We want to see it
continue in much the same way as it always has: pitched in a
scientific manner towards people who are knowledgeable on the subject,
whilst retaining its accessibility for newcomers to the hobby with
items aimed at them.  We believe that it should be presented by
professional scientists and/or highly regarded amateurs, bringing the
latest news and information on the subject to the people who want it.
We do not want to see it fronted by a generic television presenter, or
a 'celebrity' with no connection with the subject.  It is a specialist,
scientific programme and should be treated as such and with respect to
its origins and longevity.

The BBC, as a public-service broadcaster, has a remit to provide
educational programming and programming for minority audiences.
It is on that basis that it collects the licence fee from the British
public, and we feel that no programme can claim to fulfil that remit
more strongly than The Sky At Night.  Many of today's scientists and
academics have said that their enthusiasm for their subject was
inspired by the programme -- what other programmes can boast that?

This campaign has captured the imagination of the general public in
the short time that it has been running, and has now been featured in
some of the national newspapers -- the Sun, Telegraph and Daily Mail.

For more information, join the Facebook group for the campaign.

And twitter posts are using the hashtag #saveskyatnight

You can sign the petition online by visiting

Bulletin compiled by Clive Down

(c) 2013 the Society for Popular Astronomy

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)

Saturday, 21 September 2013

Vernal Equinox On Sunday.....

Equinox Arrives September 22nd
Why is the time of the equinox so specific? S&T's editors explain.
For those of us already seeing blushing foliage or feeling a chill in the air, it might seem as though autumn has already arrived. But astronomically speaking, fall officially comes to Earth's Northern Hemisphere at 20:44 Universal Time on Sunday, September 22, 2013. At that moment, the Sun's path crosses Earth's equator heading south, an event called the autumnal equinox.
The Earth's spin axis isn't at right angles to the plane of its orbit around the Sun. One consequence: the celestial-coordinate system is tilted with respect to the ecliptic (the path followed by the Sun through the stars over the course of a year). The equinoxes occur when the Sun crosses from one hemisphere to the other.
S&T / Gregg Dinderman
Why do we say summer ends and fall begins at an exact moment, when the natural events happen gradually? Because the four seasons many of us use — winter, spring, summer, and fall — have beginning and ending points defined as actual key moments in the Earth's annual orbit around the Sun — or equivalently, from our point of view, the Sun's annual motion in Earth's sky.
The Sun appears farther north or south in our sky, depending on the time of year, because of what some might consider an awkward misalignment of our planet. Earth's axis is tilted about 23½° with respect to our orbit around the Sun. That means that the plane drawn by Earth's orbit, called the ecliptic, is tilted with respect to the planet's equator. And because from our perspective the Sun follows the ecliptic in its path through the sky over the course of a year, each day the Sun's highest point in the sky moves depending on the time of year. For a skywatcher at north temperate latitudes, such as in the continental United States, the effect is to make the Sun appear to creep higher in the sky each day from late December to late June, and back down again from late June to late December. An equinox comes when the Sun is halfway through each journey.
The Earth's axial tilt is why we have seasons. When the planet is on one side of its orbit, the Northern Hemisphere is tipped sunward and gets heated by more direct solar rays, making summer. Six months later, when the planet is on the opposite side, the Northern Hemisphere is tipped away from the Sun, and the slanting solar rays heat the ground less, creating winter.
The Sun rises due east and sets due west on the equinoxes in March and September. At other times of year it comes up and goes down somewhat to the north or south. This illustration is drawn for mid-Northern latitudes.
Sky & Telescope illustration.
This celestial arrangement makes several other noteworthy things happen on the equinox date:
In the Southern Hemisphere, September's equinox marks the start of spring, and the March equinox marks the start of fall.
Day and night are almost exactly the same length; the word "equinox" comes from the Latin for "equal night." (A look in your almanac will reveal that day and night are not exactly 12 hours long at the equinox, for two reasons: First, sunrise and sunset are defined as when the Sun's top edge — not its center — crosses the horizon. Second, Earth's atmosphere distorts the Sun's apparent position slightly when the Sun is very low.
The Sun rises due east and sets due west (as seen from every location on Earth). The fall and spring equinoxes are the only times of the year when this happens.
If you were standing on the equator, the Sun would pass exactly overhead at midday. If you were at the North Pole, the Sun would skim around the horizon as the months-long polar night begins. Richard E. Byrd wrote eloquently in his 1938 book Alone of the Sun as it dove into the long Antarctic night as seen from Advance Base, 80°08'S, 163°57'W:
Huge and red and solemn, it rolled like a wheel along the Barrier edge for about two and a half hours, when the sunrise met the sunset at noon. For another two and a half hours it rolled along the horizon, gradually sinking past it until nothing was left but a blood-red incandescence. The whole effect was something like that witnessed during an eclipse. An unearthly twilight spread over the Barrier, lit by flames thrown up as from a vast pit, and the snow flamed with liquid color.
Posted by S&T Editors, September 18, 2013

Monday, 16 September 2013

The Sun Goes Strangely Quiet

Space Weather News for Sept. 14, 2013

QUIET SUN: Right in the middle of Solar Max, the sun has entered one of its deepest quiet spells in years. Flare activity has subsided and the sun's x-ray output has flatlined.  This event highlights the unpredictability of the solar cycle.  Visit for updates and commentary.

AURORAS ANYWAY: Even during a period of low solar activity, geomagnetic storms and auroras are possible as solar wind streams buffet Earth's magnetic field. Earth is inside such a stream right now. Geomagnetic storm alerts are available from (text) and (voice).

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)

Thursday, 12 September 2013

Meteor Outburst over Europe

Space Weather News for Sept. 11, 2013

METEOR NEWS: Earth is passing through a stream of debris from an unknown comet or asteroid.  It happens every year around this time and produces a minor shower known as the "September epsilon Perseids."  This year, Earth ran into an unusually dense patch of meteoroids, which produced an outburst of meteors over Europe near midnight on Sept. 9-10.  The event is highlighted on today's edition of

CHANCE OF STORMS:  NOAA forecasters estimate a 45%-50% chance of polar geomagnetic storms on Sept. 12-13 in response to an incoming solar wind stream.  This is not a major event, but it could produce bright auroras around the Arctic Circle. Geomagnetic storm alerts are available from (text) and (voice).

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
Information -- And More Info

Monday, 9 September 2013

Charts-info Astrosite Groningen (September 9, 2013)

Dear comet observers,    We have prepared the following new chart for our homepage:    C/2012 V2(LINEAR):    - a 4.5x6.0 degrees chart for the period 9 - 15 September 2013    This new chart is now available in the charts section of our   mainpage at:    Reinder Bouma/Edwin van Dijk  ----------------------------------------------------------------------------

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
Information -- And More Info

Thursday, 5 September 2013

[BAA-ebulletin 00760] New Radio Astronomy Group Newsletter

BAA electronic bulletin

The first edition of the new BAA RAG quarterly newsletter - "RAGazine" - can now be downloaded from the RAG website at  

At 66 pages, labelling it a newsletter is doing it an injustice!  Later editions will be smaller but we do have a lot to catch up on.  As the Editor explains, RAGazine is intended to be an informal way of distributing information to the amateur RA community, letting others know what people are up

A big vote of thanks needs to go to Dave James who has put a lot of time into collecting and collating the material.  Further thanks go to the individual contributors.  Please let me have your feedback and any suggestions as to what might be included in future editions using the email address below.

Paul Hyde
BAA RAG Coordinator
BAA-ebulletin mailing list visit:
(c) 2013 British Astronomical Association

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
Information -- And More Info

Tuesday, 3 September 2013

Cassini Sees Saturn Storm's Explosive Power

News feature: 2013-268                                          Sept. 3, 2013

Cassini Sees Saturn Storm's Explosive Power

The full version of this story with accompanying images is at:

A monster storm that erupted on Saturn in late 2010 – as large as any storm ever observed on the ringed planet -- has already impressed researchers with its intensity and long-lived turbulence. A new paper in the journal Icarus reveals another facet of the storm's explosive power: its ability to churn up water ice from great depths. This finding, derived from near-infrared measurements by NASA's Cassini spacecraft, is the first detection at Saturn of water ice. The water originates from deep in Saturn's atmosphere.

"The new finding from Cassini shows that Saturn can dredge up material from more than 100 miles [160 kilometers]," said Kevin Baines, a co-author of the paper who works at the University of Wisconsin-Madison and NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It demonstrates in a very real sense that typically demure-looking Saturn can be just as explosive or even more so than typically stormy Jupiter." Water ice, which originates from deep in the atmosphere of gas giants, doesn't appear to be lofted as high at Jupiter.

Monster storms rip across the northern hemisphere of Saturn once every 30 years or so, or roughly once per Saturn year. The first hint of the most recent storm first appeared in data from Cassini's radio and plasma wave subsystem on Dec. 5, 2010. Soon after that, it could be seen in images from amateur astronomers and from Cassini's imaging science subsystem. The storm quickly grew to superstorm proportions, encircling the planet at about 30 degrees north latitude for an expanse of nearly 190,000 miles (300,000 kilometers).

The new paper focuses on data gathered by Cassini's visual and infrared mapping spectrometer on Feb. 24, 2011. The team, led by Lawrence Sromovsky, also of the University of Wisconsin, found that cloud particles at the top of the great storm are composed of a mix of three substances: water ice, ammonia ice, and an uncertain third constituent that is possibly ammonium hydrosulfide. The observations are consistent with clouds of different chemical compositions existing side-by-side, though it is more likely that the individual cloud particles are composed of two or all three of the materials.

The classic model of Saturn's atmosphere portrays it as a layered sandwich of sorts, with a deck of water clouds at the bottom, ammonia hydrosulfide clouds in the middle, and ammonia clouds near the top. Those layers are just below an upper tropospheric haze of unknown composition that obscures almost everything.

But this storm appears to have disrupted those neat layers, lofting up water vapor from a lower layer that condensed and froze as it rose. The water ice crystals then appeared to become coated with more volatile materials like ammonium hydrosulfide and ammonia as the temperature decreased with their ascent, the authors said.

"We think this huge thunderstorm is driving these cloud particles upward, sort of like a volcano bringing up material from the depths and making it visible from outside the atmosphere," said Sromovsky. "The upper haze is so optically thick that it is only in the stormy regions where the haze is penetrated by powerful updrafts that you can see evidence for the ammonia ice and the water ice. Those storm particles have an infrared color signature that is very different from the haze particles in the surrounding atmosphere."

In understanding the dynamics of this Saturn storm, researchers realized that it worked like the much smaller convective storms on Earth, where air and water vapor are pushed high into the atmosphere, resulting in the towering, billowing clouds of a thunderstorm. The towering clouds in Saturn storms of this type, however, were 10 to 20 times taller and covered a much bigger area. They are also far more violent than an Earth storm, with models predicting vertical winds of more than about 300 mph (500 kilometers per hour) for these rare giant storms.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington. The California Institute of Technology in Pasadena manages JPL for NASA. The VIMS team is based at the University of Arizona in Tucson.

For more information about the Cassini mission, visit: and .


Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
Information -- And More Info

Monday, 2 September 2013

Major Fireball Event over the Southeastern USA

Space Weather News for August 30, 2013

MAJOR FIREBALL EVENT: Two nights ago, a ~100 lb meteoroid traveling 53,000 mph hit the atmosphere over the southeastern USA and exploded, producing sonic booms and a fireball as bright as a full Moon.  Researchers are now scouring the countryside for fragments that could reveal the nature and origin of the meteoroid.  A movie, more information, and updates are available on

WEEKEND AURORA WATCH: A solar wind stream is expected to hit Earth's magnetic field  on August 30-31.  The impact could produce minor geomagnetic storms and auroras at high latitudes.  Geomagnetic storm alerts are available from (text) and (voice).

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
Information -- And More Info

SPA ENB No. 360

                   The SOCIETY for POPULAR ASTRONOMY

          Electronic News Bulletin No. 360   2013 September 1

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
at 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


On October 1, Comet C/2012 S1 (ISON) will pass within 0.07 AU of
Mars, about six times closer than it will ever come to the Earth.
Mars rovers and satellites will get a close-up view.  It is uncertain
whether Curiosity will be able to see the comet from the surface of
Mars -- that depends on how much ISON brightens between now and then.
The Mars Reconnaissance Orbiter is equipped with a powerful half-metre
telescope named HiRISE that is more than capable of detecting the
comet's atmosphere and tail.  The Mars fly-by comes at a key time in
Comet ISON's journey.  It will just have crossed the 'frost line', a
place just outside the orbit of Mars where solar heating is enough to
start vaporizing frozen water.  The volatiles in a comet are 80% to
90% water ice and at present almost all the water is still frozen, and
the outgassing we see in ISON is driven by carbon dioxide and other
lesser constituents.  Probably only isolated patches of the comet's
nucleus are active.  When ISON crosses the frost line, the whole comet
could erupt in geysers of gas.  The amount of outgassing at Mars will
give researchers clues to the size of ISON's nucleus, which is hidden
from view deep within the comet's dusty atmosphere.  If ISON's nucleus
is much bigger than 0.5 km, it will probably survive its close
encounter with the Sun and might become one of the most spectacular
comets for many years.

Massachusetts Institute of Technology

Researchers have discovered an Earth-sized exoplanet named Kepler 78b
that orbits its host star in a mere 8.5 hours -- one of the shortest
planetary orbital periods so far detected.  The planet is extremely
close to its star -- its orbital radius is only about three times the
radius of the star -- and its surface temperature may be as high as
3000 K; the outer layer of the planet is probably completely melted,
forming a massive, roiling ocean of lava.  What is most exciting to
the scientists is that they were able to detect light emitted by the
planet -- the first time that researchers have been able to do so for
an exoplanet as small as Kepler 78b.  That light, when observed with
larger telescopes, may give some information about the planet's
surface composition and reflective properties.  Kepler 78b is so close
to its star that scientists hope to measure its gravitational
influence on the star.  Such information would allow an estimate to be
made of the planet's mass, which could make Kepler 78b the first
Earth-sized planet outside our own Solar System whose mass would be
known.  The star around which Kepler 78b orbits is probably relatively
young, as it rotates more than twice as fast as the Sun -- an
indication that it has not had as much time to slow down.


Astronomers have discovered a magnetar -- a pulsar with an extremely
strong magnetic field -- at the centre of the Milky Way.  It enables
researchers to investigate the immediate vicinity of the black hole at
the heart of the Galaxy.  The team has been able to measure the
strength of the magnetic field around that central object (called
Sagittarius A*, or Sgr A* for short) and was able to show that the
field controls the inflow of mass into the black hole, also explaining
the X-ray emissions.  Pulsars are extremely precise cosmic clocks, and
the one now found to be orbiting the super-massive black hole at the
centre of the Milky Way should enable measurements to be made of the
properties of space and time around that object and comparisons to be
made with Einstein's theory of General Relativity.  Shortly after the
discoveries, first by the Swift telescope of a flaring X-ray source in
the direction of the Galactic centre, and then by the NuSTAR telescope
of pulsations with a period of 3.76 seconds, a radio follow-up
programme was started with the 100-m dish pf the Effelsberg radio
observatory in Germany.

The pulsar, called PSR J1745-2900 according to its position, belongs
to a sub-group called magnetars, which are pulsars with extremely high
magnetic fields, of the order of 10 to the power 14 times stronger
than the Earth's field.  The emission from such objects is known to be
highly polarized.  Measurements of the rotation, caused by an external
magnetic field, in the plane of polarization (the Faraday effect) can
be used to infer the strength of that field along the line of sight to
the pulsar.  The black hole at the centre of the Galaxy is gradually
swallowing material from its surroundings (mainly hot ionized gas).
The field strength in the gas has not been known until now, and is an
important parameter influencing the structure and dynamics of the
accretion flow, helping or even hindering the process.  The new pulsar
has allowed measurements of the strength of the field at the beginning
of the accretion flow onto the hole, indicating that there is indeed a
large-scale and strong field.  Understanding the accretion of gas
should help astronomers to understand more generally the properties of
Sgr A*.

Science Daily

It has been suggested that there is an enormous number of free-
floating planets (not attached to stars) in the Milky Way.  Until now
it has been supposed that they would have been ejected from normal
planetary systems.  But recent observations of dark cosmic clouds
suggest that some free-floating planets formed on their own.  A team
of astronomers from Sweden and Finland observed the Rosette Nebula, a
cloud of gas and dust 4600 light-years away in the constellation
Monoceros.  They collected observations at radio wavelengths with the
20-metre telescope at Onsala in Sweden, in sub-millimetre waves with
APEX in Chile, and in infrared light with the New Technology Telescope
(NTT) at La Silla in Chile.  The Rosette Nebula has more than a
hundred dark clouds known as globules.  By astronomical standards
they are small, with diameters less than 50 times the distance between
the Sun and Neptune.  Previously astronomers were able to estimate
that most of them are of planetary mass, less than 13 times Jupiter's
mass. Now there are much more reliable measures of mass and density
for many of the objects, and of their motion relative to their

The globules are dense and compact, and many of them have very dense
cores.  Many of them will collapse under their own gravity and form
free-floating planets.  The most massive of them can form brown
dwarfs, which are bodies with masses between those of planets and
stars.  The study shows that the clouds are moving outwards through
the Rosette Nebula at about 20 km/s.  It is thought that the clouds
have broken off the tall, dusty pillars of gas that were sculpted by
the intense radiation from young stars.  They have been accelerated
out from the centre of the nebula by radiation pressure from the hot
stars there.  During the history of the Milky Way, ever so many
nebulae like the Rosette have probably bloomed and faded away.  Each
would have had many globules, and any planets and brown dwarfs that
they formed must have been launched into the depths of the Milky Way.
There are so many of them that they could be a significant source of
the free-floating planets that have been discovered in recent years.


The Kepler space telescope has had to give up its prime planet-hunting
mission after engineers were unable to restore its pointing system.
The observatory lost the second of its four gyroscopes in May, and it
can no longer hold completely steady.  Kepler has so far confirmed 135
planets beyond our Solar System.  But it still has in its data base
more than 3,500 candidates that have yet to be fully investigated, and
the majority of them are expected to be confirmed as planets in due

The 395m observatory was launched in 2009 March to try to find Earth-
sized planets orbiting their host stars in the so-called habitable
zone.  Kepler's method of detection has involved looking for the
minute dips in light, just fractions of a percent, as planets pass in
front of their stars.  The telescope has to be held absolutely still
during the observations -- something that needs a minimum of three
gyroscopes.  Kepler completed its prime mission last November, so it
has already worked beyond its minimum requirements.  But there is hope
that more science can be extracted from the spacecraft, with
suggestions that it be turned over to look for asteroids, comets and
exploding stars.  The US space agency, however, will have to decide
whether a lame Kepler merits further funding.  More planet-hunting
missions are in prospect in the coming years.  The European Space
Agency is to launch its Gaia observatory before the end of 2013.
Although its main goal is to map the positions of stars, it will do
that so precisely that it can be expected to discover thousands of
orbiting planets in the process.


Ten years after launch, the Spitzer space telescope, the last of the
four 'Great Space Observatories', warrants a celebration.  Spitzer's
infrared vision allowed it to see the far, cold and dusty parts of the
Universe.  Relatively close to home, the telescope observed Comet
Tempel 1, which was hit by the Deep Impact space craft in 2005.
Spitzer showed the composition of Tempel 1 to resemble that of solar
systems beyond our own.  It also surprised people by discovering the
largest of Saturn's rings.  That ring, a wispy band of ice and dust
particles, is very faint in visible light, but Spitzer's infrared
detectors were able to pick up the glow from its heat.  Spitzer was
the first telescope to detect light coming from a planet outside our
Solar System, a use that was not in the mission's original design.
With Spitzer's ongoing observations of such planets, astronomers have
been able to begin the study of exoplanet atmospheres.  Other
accomplishments of the mission include a census of forming stars in
nearby clouds, an improved map of the Milky Way's spiral-arm
structure, and, with Hubble, finding that the most distant galaxies
are more massive and mature than expected.

Spitzer, originally called the Space Infrared Telescope Facility, was
renamed after its launch [NASA having learnt from the initial Hubble
fiasco that it was tactless to attach people's names to spacecraft
until they had been successfully launched and proved properly
operational! -- ED] in honour of the late astronomer Lyman Spitzer.
Among the first advocates of space telescopes, he began campaigning
for them as early as the 1940s.  His efforts also led to the
development and deployment of the Hubble telescope.  In anticipation
of the Hubble launch, NASA set up the 'Great Observatories' programme,
four space telescopes designed to cover a range of wavelengths:
Hubble, Spitzer, the Chandra X-ray observatory and the now-defunct
Compton gamma-ray observatory.  Spitzer ran out of the coolant needed
for its longer-wavelength instruments in 2009, and has not been so
powerful since then.

By Tony Markhan, SPA Meteor Section Director

There was a fair amount of cloud across the UK during the nights
around Perseid maximum. However, most areas had some clear sky for
some of the time. Observers reporting the results of naked eye meteor
watches have included Tom Banks, Graham Winstanley and Ken Meadows
and Robin Scagell.

Observations from around the world, reported to the International
Meteor Organisation, have indicated that this was a fairly typical
return of the Perseids with a peak ZHR around 100 during the late
afternoon or early evening of Aug 12th - in line with predictions.
The latest IMO activity curve can be seen at

Several observers, including Alex Pratt and Peter Meadows, monitored
the Perseids using automated video camera systems and captured a
number of images of bright meteors. Readers of the SPA Forum will have
seen Bill Ward's impressive results in recording spectra of Perseid
meteors. Observations were also made at radio wavelengths, with
results being submitted by Alexei Pace and Alan Heath.

In 2014, a Full Moon on Aug 10th will make observations of the Perseid
peak more difficult, but the 2015 and 2016 Perseids will be more

Bulletin compiled by Clive Down

(c) 2013 the Society for Popular Astronomy

Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
Information -- And More Info