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Topics - Geoffw

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The Hoba Meteorite



Virtually every day, Earth is bombarded with some 100 pounds of meteoric material. Down come bits and pieces of asteroids, and similar debris composed of rock, iron, and nickel that have been encircling in space for billions of years. When they happen to fall to Earth, rarely is any damage done......... to read more CLICK HERE

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Six members attended at 2.00 p.m. on 18 September, at Sunnyridge, Newgale, for the inaugural meeting of the computer group.

There were several apologies.
It was decided that there is enough room at Sunnyridge for about 8 members to use the study and be able to  see the computer screens. With current work going on at Neyland it might even be a better temporary venue.

The next meeting will be on Tuesday 16 October at Sunnyridge at 2 p.m. (Tel. 01437 721348)

Provisional items are installing 2 monitors on one computer; how to bypass the
password when signing in to Windows; adding pictures to emails; sending emails to multiple accounts.
Using an email account to solve members simple queries was discussed.

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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 476 2018 September 16
Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is arguably 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 visiting http://www.popastro.com/
 
JUPITER HAS AN EXTRA MAGNETIC POLE
Spaceweather.com

When NASA's Juno spacecraft reached Jupiter in 2016, planetary scientists
were eager to learn more about the giant planet's magnetic field. Juno would
fly over both of Jupiter's poles, skimming just 4000 km above the cloud tops
for measurements at point-blank range. Now a team of researchers has
announced that Jupiter's magnetic field is different from all other known
planetary magnetic fields. The best way to appreciate its strangeness is by
comparison with the Earth's. Our planet has two well-defined magnetic poles
-- one in each hemisphere. This is normal. Jupiter's southern hemisphere
looks normal, too. It has a single magnetic pole located near the planet's
spin axis. Jupiter's northern hemisphere, however, is different. The north
magnetic pole is smeared into a swirl, which some writers have likened to a
'ponytail'. And there is a second south pole located near the equator. The
researchers have dubbed that extra pole 'The Great Blue Spot' because it
appears blue in their false-colour images of magnetic polarity. The
scientists consider the possibility that we are catching Jupiter in the
middle of a magnetic reversal -- an unsettled situation with temporary poles
popping up in strange places. However, they favour the idea that Jupiter's
inner magnetic dynamo is simply unlike that of other planets. Deep within
Jupiter, they posit, liquid metallic hydrogen mixes with partially dissolved
rock and ice to create strange electrical currents, giving rise to an
equally strange magnetic field. More clues could be in the offing, as Juno
continues to orbit Jupiter until 2021. Changes to Jupiter's magnetic
structure, for instance, might reveal that a reversal is under way or,
conversely, that the extra pole is stable.

WATER FOUND ON JUPITER
NASA/Goddard Space Flight Center

For centuries, scientists have worked to understand the makeup of Jupiter.
It's no wonder: that planet is the biggest one in the Solar System by far,
and chemically, the closest relative to the Sun. Understanding Jupiter is a
key to learning more about how the Solar System formed, and even about how
other solar systems develop. But one critical question has bedevilled
astronomers for generations: Is there water deep in Jupiter's atmosphere,
and if so, how much? By looking with ground-based telescopes at wavelengths
sensitive to thermal radiation leaking from the depths of Jupiter's
persistent storm, the Great Red Spot, they detected the chemical signatures
of water above the planet's deepest clouds. The pressure of the water, the
researchers concluded, combined with their measurements of another oxygen-
bearing gas, carbon monoxide, imply that Jupiter has 2 to 9 times more
oxygen than the Sun. This finding supports theoretical and computer-
simulation models that have predicted abundant water (H2O) on Jupiter made
of oxygen (O) tied up with molecular hydrogen (H2). The revelation was
stirring, given that the team's experiment could easily have failed. The
Great Red Spot is full of dense clouds, which makes it hard for electromag-
netic energy to escape and teach astronomers anything about the chemistry
within. New spectroscopic technology and sheer curiosity gave the team a
boost in peering deep inside Jupiter, which has an atmosphere thousands of
miles deep. The data the team collected will supplement the information the
Juno spacecraft is gathering as it circles the planet from pole to pole once
every 53 days. Among other things, Juno is looking for water with its own
infrared spectrometer and with a microwave radiometer that can probe deeper
than anyone has seen -- to 100 bars, or 100 times the atmospheric pressure
at Earth's surface. (Altitude on Jupiter is measured in bars, which
represent atmospheric pressure, since the planet has not got a surface,
like the Earth, from which to measure elevation.) If Juno returns similar
water findings, thereby backing the ground-based technique, it could open a
new window into solving the water problem.
Juno is the latest spacecraft tasked with finding water, probably in gas
form, on this giant gaseous planet. Water is a significant and abundant
molecule in our Solar System. It spawned life on Earth and now lubricates
many of its most essential processes, including weather. It is a critical
factor in Jupiter's turbulent weather, too, and in determining whether the
planet has a core made of rock and ice. Jupiter is thought to be the first
planet to have formed by siphoning the elements left over from the formation
of the Sun as our star coalesced from an amorphous nebula into the fiery
ball of gases we see today. A widely accepted theory until several decades
ago was that Jupiter was identical in composition to the Sun -- a ball of
hydrogen with a hint of helium -- all gas, no core. But evidence is mount-
ing that Jupiter has a core, possibly 10 times the Earth's mass. Spacecraft
that previously visited the planet found chemical evidence that it formed a
core of rock and water ice before it mixed with gases from the solar nebula
to make its atmosphere. The way Jupiter's gravity acts on Juno also
supports that theory. There's even lightning and thunder on the planet,
phenomena fuelled by moisture. The moons that orbit Jupiter are mostly
water ice, so the whole neighbourhood has plenty of water. Why wouldn't the
planet -- which is this huge gravity well, where everything falls into it --
be water rich, too? In its search for water, the team used radiation data
collected from the summit of Mauna Kea in Hawaii in 2017. They relied on
the most sensitive infrared telescope on Earth at the W.M. Keck Observatory,
and also on a new instrument that can detect a wider range of gases at the
NASA Infrared Telescope Facility. The idea was to analyze the light energy
emitted through Jupiter's clouds in order to identify the altitudes of its
cloud layers. That would help the scientists determine temperature and
other conditions that influence the types of gases that can survive in those
regions. Planetary-atmosphere experts expect that there are three cloud
layers on Jupiter: a lower layer made of water ice and liquid water, a
middle one made of ammonia and sulphur, and an upper layer made of ammonia.
To check that through ground-based observations, the team looked at wave-
lengths in the infrared range of light where most gases don't absorb heat,
allowing chemical signatures to leak out. Specifically, they analyzed the
absorption patterns of a form of methane gas. Because Jupiter is too warm
for methane to freeze, its abundance should not change from one place to
another on the planet. The team found evidence for the three cloud layers
in the Great Red Spot, supporting earlier models. The deepest cloud layer
is at 5 bars, the team concluded, right where the temperature reaches the
freezing point of water. The location of the water cloud, plus the amount
of carbon monoxide that the researchers identified on Jupiter, confirms that
Jupiter is rich in oxygen and, thus, water. The technique now needs to be
tested on other parts of Jupiter to get a full picture of global water
abundance, and the data squared with Juno's findings.

PLUTO SHOULD BE RECLASSIFIED AS A PLANET
University of Central Florida

In 2006, the International Astronomical Union established a definition of a
planet that required it to "clear" its orbit, or in other words, be the
largest gravitational force in its orbit. Since Neptune's gravity influences
its neighbouring planet Pluto, and Pluto shares its orbit with frozen gases
and objects in the Kuiper belt, that meant Pluto was out of planet status.
However, a new study reports that that standard for classifying planets is
not supported in the research literature. The study reviewed scientific
literature from the past 200 years and found only one publication -- from
1802 -- that used the clearing-orbit requirement to classify planets, and it
was based on since-disproved reasoning. Moons such as Saturn's Titan and
Jupiter's Europa have been routinely called planets by planetary scientists
since the time of Galileo. The IAU definition would mean that the funda-
mental object of planetary science, the planet, is supposed to be a defined
on the basis of a concept that nobody uses in their research. It would
leave out the second-most-complex, interesting planet in the Solar System.
We now have a list of well over 100 recent examples of planetary scientists
using the word planet in a way that violates the IAU definition, but they
are doing it because it is functionally useful. They didn't say what they
meant by clearing their orbit. If you take that literally, then there are
no planets, because no planet clears its orbit.
The study said that the literature review showed that the real division
between planets and other celestial bodies, such as asteroids, occurred in
the early 1950s when Gerard Kuiper published a paper that made the distinc-
tion based on how they were formed. However, even that reason is no longer
considered a factor that determines if a celestial body is a planet.
The IAU's definition is erroneous, since the literature review shows that
clearing of the orbit is not a standard that is used for distinguishing
asteroids from planets, as the IAU claimed when crafting the 2006 definition
of planets. Instead, the study recommends classifying a planet on the basis
of whether it is large enough for its gravity causes it to become spherical
in shape. Pluto, for instance, has an underground ocean, a multi-layer
atmosphere, organic compounds, evidence of ancient lakes and multiple moons,
he said. It is more dynamic than Mars. The only planet that has more
complex geology is the Earth.
 
EXPOLANET FOUND VERY CLOSE TO STAR
Universite de Montreal

Wolf 503b, an exoplanet twice the size of the Earth, has been discovered
by an international team of researchers using data from the Kepler Space
Telescope. Wolf 503b is about 145 light-years from the Earth in the Virgo
constellation; it orbits its star every six days and is thus very close to
it, about 10 times closer than Mercury is to the Sun. The team identified
distinct, periodic dips such as appear in the light-curve of a star when a
planet passes in front of it. In order to characterize better the system of
which Wolf 503b is part, the astronomers first obtained a spectrum of the
host star at the NASA Infrared Telescope Facility. That confirmed that the
star is an old 'orange dwarf', slightly less luminous than the Sun but about
twice as old, and allowed precise determinations of the radii both of the
star and its companion. To confirm that the companion was indeed a planet
and to avoid making a false positive identification, the team obtained
adaptive-optics measurements from Palomar Observatory and also examined
archival data. With those, they were able to confirm that there were no
binary stars in the background and that the star did not have another, more
massive, companion that could be interpreted as a transiting planet. Wolf
503b is interesting, first, because of its size. Thanks to the Kepler
telescope, we know that most of the planets in the Milky Way that orbit
close to their stars are about as big as Wolf 503b, somewhere between the
the sizes of the Earth and Neptune (which is four times bigger than the
Earth). Since there is nothing like them in the Solar System, astronomers
wonder whether these planets are small and rocky 'super-Earths' or gaseous
mini versions of Neptune. One recent discovery also shows that there are
significantly fewer planets that are between 1.5 and 2 times the size of the
Earth than those either smaller or larger than that. In their study of the
discovery, published in 2017, the researchers say that that gap, called the
Fulton gap, could be what distinguishes the two types of planets from one
another.
Wolf 503b is one of the only planets with a radius near the gap that has a
star that is bright enough to be accessible to more detailed study that will
constrain its true nature better. The second reason for interest in the
Wolf 503b system is that the star is relatively close to the Earth, and is
bright. One of the possible follow-up studies for bright stars is the
measurement of their radial velocities to determine the masses of the
planets in orbit around them. A more massive planet will have a greater
gravitational influence on its star, and the variation in line-of-sight
velocity of the star over time will be greater. The mass, together with the
radius determined by Kepler's observations, gives the bulk density of the
planet, which in turn may tell us something about its composition. For
example, at its radius, if the planet has a composition similar to that of
the Earth, it would have to be about 14 times ithe Earth's mass. If, like
Neptune, it has an atmosphere rich in gas or volatiles, it would be
approximately half as massive. Because of its brightness, Wolf 503 will
also be a prime target for the upcoming James Webb Space Telescope.
Using a technique called transit spectroscopy, it will be possible to study the
chemical content of the planet's atmosphere, and to detect the presence of
molecules like hydrogen and water. That is crucial to determine whether its
atmosphere is similar to that of the Earth, or that of Neptune, or entirely
different from the atmospheres of planets in the Solar System. Similar
observations can not be made of most planets found by Kepler, because their
host stars are usually much fainter. As a result, the bulk densities and
atmospheric compositions of most exoplanets are still unknown.

LITTLE STAR SHEDS LIGHT ON YOUNG PLANETS
University of Tokyo

The star IRAS 15398-3359) is small, young and relatively cool. Its dimin-
utive stature means that the weak light that it shines with can't even reach
us through a cloud of gas and dust that surrounds it. But that does not
stop inquisitive minds from exploring the unknown. In 2013, astronomers
used the Atacama Large Millimetre/sub-millimetre Array (ALMA) in Chile to
observe the star in sub-millimetre wavelengths, as that kind of light can
penetrate the dust cloud. Analysis revealed some interesting nebulous
structures, despite the images the astronomers worked from being difficult
to comprehend. The model describes a dense disc of material that consists
of gas and dust from the cloud that surrounds the star. Such a disc has not
previously been seen around such a young star. The disc is a precursor to a
protoplanetary disc, which is far denser still and eventually becomes a
planetary system in orbit around a star. Astronomers can't say for sure
that this particular disc will coalesce into a new planetary system. The
dust cloud may be pushed away by stellar winds or it might all fall into the
star itself. What is exciting is how quickly that might happen. The star
is small, at around 0.7 per cent of the mass of the Sun, on the basis of
observations of the mass of the surrounding cloud. It could grow to as
large as 20 per cent in just a few tens of thousands of years, a blink of
the eye on the cosmic scale. The observations and resultant model were only
possible thanks to advances in radio astronomy with observatories such as
ALMA. The team was lucky that we see the disc practically edge-on, so the
starlight ALMA sees passes through enough of the gas and dust of the disc to
divulge important characteristics of it.

SUPERNOVAE CLUE TO STELLAR EVOLUTION
National Institutes of Natural Sciences

At the end of its life, a red supergiant star explodes as a hydrogen-rich
supernova. By comparing observational results to simulation models, an
international research team found that in many cases the explosion takes
place inside a thick cloud of circumstellar matter shrouding the star. That
result completely changes our understanding of the last stage of stellar
evolution. The research team used the Blanco Telescope to find 26 super-
novae coming from red supergiants. Their goal was to study the shock
breakout, a brief flash of light preceding the main supernova explosion.
But they could not find any signs of that phenomenon. On the other hand, 24
of the supernovae brightened faster than expected. To solve that mystery,
astronomers simulated 518 models of supernova brightness variations and
compared them with the observational results. The team found that models
with a layer of circumstellar matter about 10% of the mass of the Sun
surrounding the supernovae matched the observations well. The circumstellar
matter hides the shock breakout, trapping its light. The subsequent
collision between the supernova ejecta and the circumstellar matter creates
a strong shock wave that produces extra light, causing it to brighten more
quickly. Near the end of its life, some mechanism in the star's interior
must cause it to shed mass that then forms a layer around the star. We do
not yet have a clear idea of the mechanism causing such mass loss; further
study is needed. That will also be important in revealing the supernova
explosion mechanism and the origin of the diversity in supernovae.

CONFIRMATION OF SUPER-FAST JET FROM STAR MERGER
National Radio Astronomy Observatory

Precise measurement using a continent-wide collection of National Science
Foundation (NSF) radio telescopes has revealed that a narrow jet of
particles moving at nearly the speed of light broke out into interstellar
space after a pair of neutron stars merged in a galaxy 130 million light-
years away. The merger, which occurred in 2017 August, sent gravitational
waves rippling through space. It was the first event ever to be detected
both by gravitational waves and electromagnetic waves, including gamma rays,
X-rays, visible light, and radio waves. The aftermath of the merger, called
GW170817, was observed by orbiting and ground-based telescopes around the
world. Scientists watched as the characteristics of the received waves
changed with time, and used the changes as clues to reveal the nature of the
phenomena that followed the merger. One question that stood out, even
months after the merger, was whether or not the event had produced a narrow,
fast-moving jet of material that made its way into interstellar space. That
was important, because such jets are required to produce the type of gamma-
ray bursts that theorists had said should be caused by the merger of
neutron-star pairs. The answer came when astronomers used a combination of
the NSF's Very Long Baseline Array (VLBA), the Karl G. Jansky Very Large
Array (VLA), and the Robert C. Byrd Green Bank Telescope (GBT) and discovered that a region of radio emission from the merger had moved, and the motion was so fast that only a jet could explain its speed. They measured an
apparent motion that is four times faster than light. That illusion, called
superluminal motion, results when the jet is pointed nearly towards the
Earth and the material in the jet is moving close to the speed of light.
The astronomers observed the object 75 days after the merger, then again 230
days after. The jet is likely to be very narrow, at most 5 degrees wide,
and was pointed only 20 degrees away from the Earth's direction. To match
the observations, the material in the jet has to be blasting outwards at
over 97% of the speed of light.
The scenario that emerges is that the initial merger of the two super-dense
neutron stars caused an explosion that propelled a spherical shell of debris
outward. The neutron stars collapsed into a black hole whose powerful
gravity began pulling material towards it. That material formed a rapidly-
spinning disc that generated a pair of jets moving outwards from its poles.
As the event unfolded, the question became whether the jets would break out
of the shell of debris from the original explosion. Data from observations
indicated that a jet had interacted with the debris, forming a broad
'cocoon' of material expanding outward. Such a cocoon would expand more
slowly than a jet. The scientists said that the detection of a fast-moving
jet in GW170817 greatly strengthens the connection between neutron-star
mergers and short-duration gamma-ray bursts. They added that the jets need
to be pointed relatively accurately towards the Earth for the gamma-ray
burst to be detected. The merger event was important for a number of
reasons, and it continues to surprise astronomers with more information.
Jets are enigmatic phenomena seen in a number of environments, and now these exquisite observations in the radio part of the electromagnetic spectrum are providing fascinating insight into them, helping us to understand how they
work.

UNSTOPPABLE MONSTER IN EARLY UNIVERSE:
National Institutes of Natural Sciences

Astronomers have obtained the most detailed anatomy chart of a monster
galaxy located 12.4 billion light-years away. Using the Atacama Large
Millimetre/submillimetre Array (ALMA), the team revealed that the molecular
clouds in the galaxy are highly unstable, which leads to runaway star
formation. Monster galaxies are thought to be the ancestors of the huge
elliptical galaxies in today's Universe, therefore these findings pave the
way to understand the formation and evolution of such galaxies. Monster
galaxies, or starburst galaxies, form stars at a startling pace, 1000 times
higher than the star formation in our Galaxy. But why are they so active?
To tackle that problem, researchers need to know the environment around the
stellar nurseries. Drawing detailed maps of molecular clouds is an important
step to scout a cosmic monster. The team targeted a chimerical galaxy,
COSMOS-AzTEC-1. That galaxy was first discovered with the James Clerk
Maxwell Telescope in Hawaii, and later the Large Millimetre Telescope (LMT)
in Mexico found an enormous amount of carbon monoxide gas in the galaxy and
revealed its hidden starburst. The LMT observations also measured the
distance to the galaxy, and found that it is 12.4 US-billion light-years.
Researchers have found that COSMOS-AzTEC-1 is rich with the ingredients of
stars, but it was still difficult to figure out the nature of the cosmic gas
in the galaxy. The team utilized the high resolution and high sensitivity
of ALMA to observe this monster galaxy and obtain a detailed map of the
distribution and the motion of the gas. Thanks to the most extended ALMA
antenna configuration of 16 km, this is the highest-resolution molecular-gas
map of a distant monster galaxy ever made.
The team found that there are two distinct large clouds several thousand
light-years away from the centre. In most distant starburst galaxies, stars
are actively formed in the centre, so it is surprising to find off-centre
clouds. The astronomers further investigated the nature of the gas in
COSMOS-AzTEC-1 and found that the clouds throughout the galaxy are very
unstable, which is unusual. In a normal situation, the inward gravity and
outward pressure are balanced in the clouds. Once gravity overcomes
pressure, the gas cloud collapses and forms stars at a rapid pace. Then,
stars and supernova explosions at the end of the stellar life-cycle blast
out gases, which increase the outward pressure. As a result, the gravity
and pressure reach a balanced state and star formation continues at a
moderate pace. In that way star formation in galaxies is self-regulating.
But, in COSMOS-AzTEC-1, the pressure is far weaker than the gravity and hard
to balance. Therefore that galaxy shows runaway star formation and has
morphed into an unstoppable monster galaxy. The team estimated that the gas
in COSMOS-AzTEC-1 will be completely consumed in 100 million years, which is 10 times faster than in other star-forming galaxies. But why is the gas in
COSMOS-AzTEC-1 so unstable? Researchers have not got a definitive answer
yet, but galaxy merger is a possible cause. Galaxy collision may have
transported the gas efficiently into a small area and ignited intense star
formation. At this moment, however, astronomers have no evidence of any
merger in that galaxy. By observing other similar galaxies with ALMA,
astronomers hope to elucidate the relationship between galaxy mergers and
monster galaxies.

Bulletin compiled by Clive Down
(c) 2018 The Society for Popular Astronomy
www.popastro.com







4
Art Groups / Breaking out of the Gallery exhibition closes with a party
« on: September 17, 2018, 08:20:35 AM »
Breaking out of the Gallery exhibition closes with a party



The Breaking out of the Gallery exhibition asks local artists both professional and amateur to create paintings, collages and mixed media images on large boards which are mounted around the streets of Pembrokeshire’s county town for the summer months.

All of the images have now been brought together for a final exhibition at 8 Spring Gardens.

A total of 70 works from 50 artists were hung around Haverfordwest for this, the exhibition’s third year, based around the theme of Brighter Futures
“It is really exciting to have exhibited work from so many artists this year,” said Arthur Brooker, who founded the project. “We have had a great reception from the public who seem to have really enjoyed it and business owners as well. Special thanks to the artists and business owners for making it all possible, and all the other people who have helped along the way,” he added. “There was also participation from pupils at Redhill School, who painted 10 small paintings for the exhibition, with help from their teacher Owen Hart.  It was nice to include some younger artists from Pembrokeshire in this year’s exhibition,” said Arthur.  “We are looking forward to running future projects.”

The Breaking out of the Gallery exhibition can be viewed at 8 Spring Gardens until Friday, September 21.

The project will celebrate the end of its third year with a party at Spring Gardens on Friday, September 21 from 6pm until late.

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What's On in Pembrokeshire / Pembroke Soup Sat 22nd Sept
« on: September 14, 2018, 08:33:00 AM »
SUPPORTS COMMUNITY PROJECTS
Come along! You pay just £4.00 to:-
•   eat delicious donated soup;
•   find out about 4 Community projects in the Pembroke area;
•   silently vote for how the day’s door money is then distributed to community project.
(No charge for children under 10 yrs with adult)
Got an idea for a project to benefit Pembroke? We invite you to apply to make a four minute pitch to present at PEMBROKE SOUP. As well as the chance for an instant cash grant,you could gain publicity; support;receive ideas from the community to help make your project happen.           
SAT 22nd September 12.00 TO 1.30pm
PEMBROKE TOWN HALL.COME AND FIND OUT ABOUT:-
•   CLEDDAU CORICLES
•   IRISH DANCING
•   LIFEBOATS
•   HOW TALL IS YOUR SUNFLOWER?

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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 475 2018 Sept 2
Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is arguably 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 visiting http://www.popastro.com/
 
STUDY SHOWS EARTH'S INGREDIENTS ARE NORMAL
Goldschmidt Conference

The Earth's building blocks seem to be built from 'pretty normal'
ingredients, according to researchers working with the world's most powerful
telescopes. Scientists have measured the compositions of 18 different
planetary systems from up to 456 light-years away and compared them to ours,
and found that many elements are present in similar proportions to those
found on Earth. This is amongst the largest examinations to measure the
general composition of materials in other planetary systems, and begins to
allow scientists to draw more general conclusions on how they are forged,
and what that might mean for finding Earth-like bodies elsewhere. The first
planets orbiting other stars were not found until 1992 (the first one was
orbiting a pulsar); since then scientists have been trying to understand
whether some of the stars and planets are similar to our own Solar System.
It is difficult to examine remote planets directly; the nearby star tends to
overwhelm any electromagnetic signal, such as light or radio waves. Because
of that, the team decided to look at how the planetary building blocks
affect signals from white-dwarf stars. Those are stars which have burnt up
most of their hydrogen and helium, and shrunk to be very small and dense --
it is anticipated that our Sun will become a white dwarf in around 5 billion
years. White dwarfs' atmospheres are composed of either hydrogen or helium,
which give out a pretty clear and clean spectroscopic signal. However, as
the star cools, it begins to pull in material from the planets, asteroids,
comets and so on which had been orbiting it, with some forming a dust disk,
a little like the rings of Saturn. As that material approaches the star, it
changes how we see the star. The change is measurable because it influences
the star's spectroscopic signal, and allows us to identify the type and even
the quantity of material surrounding the white dwarf. Such measurements can
be extremely sensitive, allowing bodies as small as an asteroid to be
detected.
The team took measurements with spectrographs on the Keck telescope in
Hawaii, the world's largest optical and infrared telescope, and on the
Hubble Space Telescope. In that study, the team focused on the sample of
white dwarfs with dust disks. Astronomers were able to measure the calcium,
magnesium, and silicon content in most of those stars, and a few additional
elements in some of them. They may also have found water in one of the
systems, but have not yet quantified it: it is likely that there will be a
lot of water in some of those objects. For example, the team previously
identified one star system, 170 light-years away in the constellation
Bootes, which was rich in carbon, nitrogen and water, giving a composition
similar to that of Halley's Comet. In general, though, their composition
looks very similar to that of the Earth. That would mean that the chemical
elements, the building blocks of the Earth, are common in other planetary
systems. From what can be seen, in terms of the presence and proportion of
those elements, we are normal, pretty normal. And that means that we can
probably expect to find Earth-like planets elsewhere in our Galaxy. This
work is still on-going and the recent data release from the Gaia satellite,
which so far has characterized 1.7 billion stars, has revolutionized the
field. That means that we will understand the white dwarfs a lot better.
The team hopes to determine the chemical compositions of extra-solar
planetary material to a much higher precision.

STEVE IS NOT AN AURORA
Spaceweather.com

A new type of aurora nicknamed 'STEVE' may not be an aurora at all,
according to a group of researchers who combined satellite data with
ground-based imagery during a geomagnetic storm to investigate how STEVE is
formed. The main conclusion is that STEVE is not an aurora. STEVE is a
purple ribbon of light that amateur astronomers in Canada have been
photographing for decades, belatedly catching the attention of the
scientific community in 2016. It doesn't look exactly like an aurora, but
it often appears alongside aurorae during geomagnetic storms. Is it an
aurora -- or not? That's what the team wanted to find out. Aurorae appear
when energetic particles from space rain down on the Earth's atmosphere
during geomagnetic storms. If STEVE is an aurora, they reasoned, it should
form in much the same way. On 2008 March 28, STEVE appeared over eastern
Canada just as NOAA's Polar Orbiting Environmental Satellite 17 (POES-17)
passed overhead. The satellite, which can measure the rain of charged
particles that causes aurorae, went directly above the purple ribbon. The
team looked carefully at the old data and found ... no rain at all. The
results verify that that STEVE event is clearly distinct from the aurora
borealis since it is characterized by the absence of particle precipitation.
Interestingly, its skyglow could be generated by a new and fundamentally
different mechanism in the Earth's ionosphere. Another study has shown that
STEVE appears most often in spring and autumn. With the next equinox only a
month away, new opportunities to study STEVE are just around the corner.

A GREEN COMET APPROACHES THE EARTH
Spaceweather.com

Comet 21P/Giacobini-Zinner is approaching the Earth. On Sept. 10, it will
be 0.39 AU (58 million km) from our planet and almost bright enough to see
with the naked eye. Already it is an easy target for amateur telescopes.
The comet is relatively small -- its nucleus is barely more than a mile in
diameter -- but it is bright and active, and a frequent visitor to the
inner Solar System as it orbits the Sun once every 6.6 years. On Sept. 10,
21P/Giacobini-Zinner will not only be near the Earth, but also at peri-
helion, its closest approach to the Sun. Solar heating will make it
shine like a star of 6th to 7th magnitude, just below the threshold of
naked-eye visibility but well within the range of common binoculars.
21P/Giacobini-Zinner is the parent of the annual Draconid meteor shower, a
bursty display that typically peaks on Oct. 8. Will the shower be extra
good this year? Draconid outbursts do tend to occur in years near the
comet's close approach to the Sun. However, not every close approach brings
a meteor shower. Forecasters say that there are no known Draconid debris
streams squarely crossing the Earth's path this year, so we will have to
wait and see.

ICE CONFIRMED AT MOON'S POLES
NASA/Jet Propulsion Laboratory

A team of scientists has directly observed definitive evidence of water ice
on the Moon's surface, in the darkest and coldest parts of the Moon's polar
regions. The ice deposits are patchily distributed and could possibly be
ancient. At the southern pole, most of the ice is concentrated in craters,
while the northern pole's ice is more widely, but sparsely, spread. A team
of scientists used data from NASA's Moon Mineralogy Mapper (M3) instrument
to identify three specific signatures that definitively prove that there is
water-ice on the surface of the Moon. M3, aboard the Chandrayaan-1 space-
craft, launched in 2008 by the Indian Space Research Organization, was
equipped to confirm the presence of solid ice on the Moon. It collected
data that not only picked up the reflective properties we would expect from
ice, but by infrared spectroscopy it could differentiate between liquid
water or vapour and solid ice. Most of the newfound water ice lies in the
shadows of craters near the poles, where the temperature never reaches above
minus 157 Centigrade. Because of the very small tilt of the Moon's rotation
axis, sunlight never reaches those regions. Previous observations indirect-
ly found possible signs of surface ice at the lunar south pole, but they
could have been explained by other phenomena, such as unusually reflective
lunar soil. With enough ice sitting at the surface -- within the top few
millimetres -- water would possibly be accessible as a resource for future
expeditions to explore and even stay on the Moon, and potentially easier to
access than the water detected beneath the Moon's surface.

INSIGHT PASSES HALFWAY POINT TO MARS
NASA

NASA's InSight spacecraft, en route to a Nov. 26 landing on Mars, passed the
halfway mark on Aug. 6. All of its instruments have been tested and are
working well. The spacecraft has covered 300 million kilometres since its
launch. It will touch down in Mars' Elysium Planitia region, where it will
be the first mission to study the planet's deep interior. InSight stands
for Interior Exploration using Seismic Investigations, Geodesy and Heat
Transport. The InSight team is using the time before the spacecraft's
arrival at Mars not only to plan and practise for that critical day,
but also to activate and check spacecraft sub-systems vital to cruise,
landing and surface operations, including the highly sensitive scientific
instruments. InSight's seismometer, which will be used to detect quakes on
Mars, received a clean bill of health on July 19. The SEIS instrument
(Seismic Experiment for Interior Structure) is a six-sensor seismometer
combining two types of sensors to measure ground motions over a wide range
of frequencies. It will give scientists a window into Mars' internal
activity.

STRUCTURALLY 'INSIDE OUT' PLANETARY NEBULA DISCOVERED
The University of Hong Kong

Astronomers have discovered the unusual evolution of the central star of a
planetary nebula in our Milky Way. That discovery sheds light on the future
evolution, and more importantly, the ultimate fate of the Sun. The research
team believes that the inverted ionization structure of the nebula is the
result of the central star undergoing a 'born-again' event, ejecting
material from its surface and creating a shock that excites the nebular
material. Planetary nebulae are ionized clouds of gas formed by the
hydrogen-rich envelopes ejected at late evolutionary stages of low- and
intermediate-mass stars. As such stars age, they typically strip their
outer layers, forming a 'wind'. As the star transitions from its red-giant
phase to become a white dwarf, it becomes hotter, and starts ionizing the
material in the surrounding wind. That causes the gaseous material closer
to the star to become highly ionized, while the material further out is less
so. Studying the planetary nebula HuBi 1 (17,000 light-years away and
nearly 5 billion years ahead of our Solar System in evolution), however,
the team found the reverse: HuBi 1's inner regions are less ionized, while
the outer regions are more so. Analysing the central star, with the
participation of theoretical astrophysicists, the authors found that it
is surprisingly cool and metal-rich, and has evolved from a low-mass
progenitor star which had a mass 1.1 times that of the Sun. The authors
suggest that the inner nebula was excited by the passage of a shock wave
caused by the star ejecting matter unusually late in its evolution. The
stellar material cooled to form circumstellar dust, obscuring the star; that
would explain why the central star's optical brightness has diminished
rapidly over the past 50 years. In the absence of ionizing photons from the
central star, the outer nebula has begun recombining -- becoming neutral.
The authors conclude that, as HuBi 1 was roughly the same mass as the Sun,
this finding may provide a glimpse of a potential future for our Solar
System.
The discovery resolves a long-lasting question regarding the evolutionary
path of metal-rich central stars of planetary nebulae. The team has been
using the Nordic Optical Telescope to observe the evolution of HuBi 1 since
2014, and was among the first astrophysicists to discover its inverted
ionization structure. After noting that structure and the unusual nature of
HuBi 1's central star, the observers collaborated with theoretical astro-
physicists in an effort to find the reasons for what they had observed.
They came to realize that they had caught HuBi 1 at the exact time when its
central star underwent a brief 'born-again' process to become a hydrogen-
poor [WC] and metal-rich star, which is very rare in white-dwarf stars'
evolution. The findings suggest that the Sun may also experience a 'born-
again' process while it is dying, about 5000 million years from now; but
long before that event the Earth will be engulfed by the Sun when it expands
into a red giant and nothing living will survive.

WATER WORLDS ARE COMMON
Goldschmidt Conference

Scientists have shown that water is likely to be a major component of those
exoplanets (planets orbiting other stars) which are between two and four
times the size of the Earth. That has implications for the search for life
in our Galaxy. The 1992 discovery of exoplanets orbiting other stars has
sparked interest in understanding the compositions of those planets, to
determine, among other goals, whether they are suitable for the development
of life. Now a new evaluation of data from the exoplanet-hunting Kepler
Space Telescope and the Gaia mission indicates that many of the known
planets may contain as much as 50% water. That is very much more than the
Earth's 0.02% (by weight) water content. Scientists have found that many of
the 4000 confirmed or candidate exoplanets discovered so far fall into two
size categories: those with the planetary radii averaging around 1.5 times
that of the Earth, and those averaging around 2.5 Earth radii. Now a group
of scientists, after analyzing the exoplanets with mass measurements and
recent radius measurements from the Gaia satellite, has developed a model
of their internal structure. The group has looked at how mass relates to
radius, and developed a model which might explain the relationship. The
model indicates that those exoplanets which have radii of around 1.5 Earth
radii tend to be rocky planets (of typically five times the mass of the
Earth), while those with radii of about 2.5 Earth radii (with masses around
ten times that of the Earth) are probably water worlds.
Their water is not as is commonly found here on Earth. Their surface
temperatures are expected to be in the 200- to 500-degree Celsius range.
Their surfaces may be shrouded in a water-vapour-dominated atmosphere, with
a liquid water layer underneath. Deeper down, one would expect to find the
that the water transforms into high-pressure ices before one reaches the
solid rocky core. The beauty of the model is that it explains just how
composition relates to the known facts about such planets. The data
indicate that about 35% of all known exoplanets which are bigger than the
Earth should be water-rich. Those water worlds probably formed in ways
similar to the giant-planet cores (Jupiter, Saturn, Uranus, Neptune) which
we find in our own Solar System. The newly-launched TESS mission is
expected to find many more of them, with the help of ground-based spectro-
scopic follow-up.

GALAXY CLUSTER HIDING IN PLAIN SIGHT
Massachusetts Institute of Technology

MIT scientists have uncovered a sprawling new galaxy cluster hiding in plain
sight. The cluster, which is 2.4 billion light-years away, is made up of
hundreds of individual galaxies and surrounds an extremely active super-
massive black hole, or quasar. The central quasar is called PKS1353-341 and
is intensely bright -- so bright that for decades astronomers observing it
in the night sky have assumed that the quasar was quite alone in its corner
of the Universe, shining out as a solitary light source from the centre of a
single galaxy. The researchers estimate that the cluster has a mass of
about 690 times 10 to the 12 Suns. Our Milky Way galaxy, for comparison,
weighs in at around 400,000 million solar masses. The team also calculates
that the quasar at the centre of the cluster is 46 billion times brighter
than the Sun. Its extreme luminosity is probably the result of a temporary
feeding frenzy: as an immense disk of material swirls around the quasar, big
chunks of matter from the disk are falling in and feeding it, causing the
black hole to radiate huge amounts of energy out as light. That might be a
short-lived phase that clusters go through, where the central black hole has
a quick meal, gets bright, and then fades away again. Some astronomers
believe that the discovery of the hidden cluster inplies there may be other
similar galaxy clusters hiding behind extremely bright objects that
astronomers have mis-catalogued as single light sources. The researchers
are now looking for more hidden galaxy clusters, which could be important
clues to estimating how much matter there is in the Universe and how fast
the Universe is expanding.
In 2012, the team discovered the Phoenix cluster, one of the most massive
and luminous galaxy clusters in the Universe. The mystery was why that
cluster, which was so intensely bright and in a region of the sky that is
easily observable, had not been found before. It is because astronomers had
preconceived notions of what a cluster should look like. For the most part,
astronomers have assumed that galaxy clusters look 'fluffy', giving a very
diffuse signal in the X-ray band, unlike brighter, point-like sources, which
have been interpreted as extremely active quasars or black holes. The
images are either all points, or fluffs; the points are black holes that are
accreting gas and glowing as the gas spirals in, and the fluffs are great
million-light-year balls of hot gas that we call clusters. The Phoenix
discovery proved that galaxy clusters could indeed host immensely active
black holes, prompting astronomers to wonder whether there could be other
'nearby' galaxy clusters that were simply misidentified. To answer that
question, the researchers set up a survey named CHiPS, for Clusters Hiding
in Plain Sight, which was designed to re-evaluate X-ray images taken in the
past. For every point source that was previously identified, the
researchers noted the coordinates and then studied them more directly with
the Magellan Telescope, a powerful optical telescope in Chile. If they
observed a higher-than-expected number of galaxies surrounding the point
source (a sign that the gas may stem from a cluster of galaxies), the
researchers looked at the source again, using NASA's space-based Chandra
X-Ray Observatory, to identify an extended, diffuse source around the main
point source. Some 90% of the sources turned out to not be clusters. The
team plans to comb through more X-ray data in search of galaxy clusters that
might have been missed the first time.

SOME OF THE OLDEST GALAXIES IN UNIVERSE
Durham University

Astronomers from the Institute for Computational Cosmology at Durham
University and the Harvard-Smithsonian Center for Astrophysics have found
evidence that the faintest satellite galaxies orbiting our own Milky Way
galaxy are amongst the very first galaxies that formed in the Universe.
Scientists working on that research have described the finding as "hugely
exciting". The research group's findings suggest that galaxies including
Segue-1, Bootes I, Tucana II and Ursa Major I are in fact some of the first
galaxies ever formed, thought to be over 13 billion years old. When the
Universe was about 380,000 years old, the very first atoms formed. They
were atoms of hydrogen, the simplest element in the Periodic Table. Those
atoms collected into clouds and began to cool gradually and settle into the
small clumps or 'haloes' of dark matter that emerged from the Big Bang.
That cooling phase, known as the 'Cosmic dark ages', lasted about 100
million years. Eventually, the gas that had cooled inside the haloes
became unstable and began to form stars -- these objects are the very first
galaxies ever to have formed. With the formation of the first galaxies, the
Universe burst into light, bringing the cosmic dark ages to an end.
The team identified two populations of satellite galaxies orbiting the Milky
Way. The first was a very faint population consisting of the galaxies that
formed during the 'cosmic dark ages'. The second was a slightly brighter
population consisting of galaxies that formed hundreds of millions of years
later, once the hydrogen that had been ionized by the intense ultraviolet
radiation emitted by the first stars was able to cool into more massive dark
matter haloes. Remarkably, the team found that a model of galaxy formation
that it had developed previously agreed perfectly with the data, allowing it
to infer the formation times of the satellite galaxies. The finding
supports the current model for the evolution of the Universe, the 'Lambda-
cold-dark-matter model' in which the elementary particles that make up the
dark matter drive cosmic evolution. The intense ultraviolet radiation
emitted by the first galaxies destroyed the remaining hydrogen atoms by
ionizing them (knocking out their electrons), making it difficult for that
gas to cool and form new stars. The process of galaxy formation ground to a
halt and no new galaxies were able to form for the next billion years or so.
Eventually, the haloes of dark matter became so massive that even ionized
gas was able to cool. Galaxy formation resumed, culminating in the formation
of spectacular bright galaxies like our own Milky Way. A decade ago, the
faintest galaxies in the vicinity of the Milky Way would have gone under the
radar. With the increasing sensitivity of present and future galaxy counts,
a whole new trove of the tiniest galaxies has come to light, allowing us to
test theoretical models in new regimes.

EARLY OPAQUE UNIVERSE LINKED TO GALAXY SCARCITY
University of California - Riverside

A team of astronomers has made a surprising discovery: 12.5 billion years
ago, the most opaque place in the Universe contained relatively little
matter. It has long been known that the Universe is filled with a web-like
network of dark matter and gas. That 'cosmic web' accounts for most of the
matter in the Universe, whereas galaxies like our own Milky Way make up only
a small fraction. Today, the gas between galaxies is almost totally
transparent because it is kept ionized -- electrons detached from their
atoms -- by a bath of energetic ultraviolet radiation. Over a decade ago,
astronomers noticed that in the very distant past -- roughly 12.5 billion
years ago, or about 1 billion years after the Big Bang -- the gas in deep
space was not only highly opaque to ultraviolet light, but its transparency
varied widely from place to place, obscuring much of the light emitted by
distant galaxies. Then a few years ago, a team at the University of
Cambridge found that those differences in opacity were so large that either
the amount of gas itself, or more likely the radiation in which it is
immersed, must vary substantially from place to place. Today, we live in a
fairly homogeneous Universe. If you look in any direction you find, on
average, roughly the same number of galaxies and similar properties for the
gas between galaxies, the so-called intergalactic gas. At that early time,
however, the gas in deep space looked very different from one region of the
Universe to another. To find out what created the differences, astronomers
used one of the largest telescopes in the world, the Subaru telescope on the
summit of Mauna Kea in Hawaii. Using its powerful camera, the team looked
for galaxies in a vast region, roughly 300 million light-years in size,
where they knew the intergalactic gas was extremely opaque.
For the cosmic web, more opacity normally means more gas, and hence more
galaxies. But the team found the opposite: the region contained far fewer
galaxies than average. Because the gas in deep space is kept transparent by
the ultraviolet light from galaxies, fewer galaxies nearby might make it
murkier. Normally it does not matter how many galaxies are nearby; the
ultraviolet light that keeps the gas in deep space transparent often comes
from galaxies that are extremely far away. At that very early time, it
looks as if the UV light could not travel very far, so a patch of the
Universe with few galaxies in it would look much darker than one with plenty
of galaxies around. That discovery may eventually shed light on another
phase in cosmic history. In the first billion years after the Big Bang,
ultraviolet light from the first galaxies filled the Universe and
permanently transformed the gas in deep space. Astronomers believe that
that occurred earlier in regions with more galaxies, so the large fluctua-
tions in intergalactic radiation may be a relic of that patchy process, and
could offer clues to how and when it occurred. By studying both galaxies
and the gas in deep space, astronomers hope to get closer to understanding
how the intergalactic ecosystem took shape in the early Universe.

ANCIENT QUASARS CONFIRM QUANTUM ENTANGLEMENT
Massachusetts Institute of Technology

Last year, physicists at MIT, the University of Vienna, and elsewhere
provided strong support for quantum entanglement, the seemingly far-out idea
that two particles, no matter how distant from each other in space and time,
can be inextricably linked, in a way that defies the rules of classical
physics. Take, for instance, two particles sitting on opposite edges of the
Universe. If they are truly entangled, then according to the theory of
quantum mechanics their physical properties should be related in such a way
that any measurement made on one particle should instantly convey
information about any future measurement outcome of the other particle --
correlations that Einstein sceptically saw as "spooky action at a distance".
In the 1960s, the physicist John Bell calculated a theoretical limit beyond
which such correlations must have a quantum, rather than a classical,
explanation. But what if such correlations were the result not of quantum
entanglement, but of some other hidden, classical explanation? Such
"what-ifs" are known to physicists as loopholes to tests of Bell's
inequality, the most stubborn of which is the 'freedom-of-choice' loophole:
the possibility that some hidden, classical variable may influence the
measurement that an experimenter chooses to perform on an entangled
particle, making the outcome look quantumly correlated when in fact it
isn't. Last February, the MIT team and their colleagues significantly
constrained the freedom-of-choice loophole, by using 600-year-old starlight
to decide what properties of two entangled photons to measure. Their
experiment proved that, if a classical mechanism caused the correlations
they observed, it would have to have been set in motion more than 600 years
ago, before the stars' light was first emitted and long before the actual
experiment was even conceived. Now, the same team has vastly extended the
case for quantum entanglement and further restricted the options for the
freedom-of-choice loophole. The researchers used distant quasars, one of
which emitted its light 7.8 billion years ago and the other 12.2 billion
years ago, to determine the measurements to be made on pairs of entangled
photons. They found correlations among more than 30,000 pairs of photons,
to a degree that far exceeded the limit that Bell originally calculated for
a classically based mechanism. If some conspiracy is happening to simulate
quantum mechanics by a mechanism that is actually classical, that mechanism
would have had to begin its operations -- somehow knowing exactly when,
where, and how this experiment was going to be done -- at least 7.8 billion
years ago. That seems incredibly implausible, so we have very strong
evidence that quantum mechanics is the right explanation. The Earth is
about 4.5 billion years old, so any alternative mechanism -- different from
quantum mechanics -- that might have produced our results by exploiting such
a loophole would have had to be in place long before even there was a planet
Earth, let alone an MIT. So we have pushed any alternative explanations
back to very early in cosmic history.

15 YEARS IN SPACE FOR SPITZER SPACE TELESCOPE
NASA

Initially scheduled for a minimum 2.5-year primary mission, NASA's Spitzer
Space Telescope has gone far beyond its expected lifetime -- and is still
going strong after 15 years. Launched into a solar orbit on 2003 Aug. 25,
Spitzer was the last of NASA's four Great Observatories to reach space. The
space telescope has illuminated some of the oldest galaxies in the Universe,
revealed a new ring around Saturn, and peered through shrouds of dust to
study newborn stars and black holes. Spitzer assisted in the discovery of
planets beyond our Solar System, including the detection of seven Earth-size
planets orbiting the star TRAPPIST-1, among other accomplishments. Spitzer
detects infrared light -- most often heat radiation emitted by warm objects.
Each of the four Great Observatories collects light in a different range of
wavelength. By combining their observations of various objects and regions,
scientists can gain a more complete picture of the Universe. Spitzer has
logged over 106,000 hours of observation time. Thousands of scientists
around the world have utilized Spitzer data in their studies, and Spitzer
data are cited in more than 8,000 published papers.
Spitzer's primary mission ended up lasting 5.5 years, during which time the
spacecraft operated in a 'cold phase', with a supply of liquid helium
cooling three onboard instruments to just above absolute zero. The cooling
system reduced excess heat from the instruments themselves that could
contaminate their observations. That gave Spitzer very high sensitivity for
'cold' objects. In 2009 July, after Spitzer's helium supply ran out, the
spacecraft entered a so-called 'warm phase'. Spitzer's main instrument,
called the Infrared Array Camera (IRAC), has four cameras, two of which
continue to operate in the warm phase with the same sensitivity that they
maintained during the cold phase. Spitzer orbits the Sun in an Earth-
trailing orbit (meaning it literally follows behind the Earth as the planet
orbits the Sun) and has continued to fall further and further behind the
Earth during its lifetime. This now poses a challenge for the spacecraft,
because while it is downloading data to Earth, its solar panels do not
directly face the Sun. As a result, Spitzer must use battery power during
data downloads. The batteries are then recharged between downloads. In
2016, Spitzer entered an extended mission dubbed 'Spitzer Beyond'. The
spacecraft is currently scheduled to continue operations till 2019 November,
more than 10 years after entering its warm phase.

Bulletin compiled by Clive Down
www.popastro.com



8
Astronomy Group / The Night Sky This Month – September 2018
« on: September 01, 2018, 09:05:27 AM »
The Night Sky This Month – September 2018


The zodiacal light as seen from La Silla, Chile (credit: ESO).

September’s arrived, and that means stargazers have a final few weeks to see the long, starry arc of the Milky Way and all its attendant splendor. The rich constellations of Scorpius and Sagittarius are moving westward, but the lengthening nights keep these stars accessible for a little longer, at least for observers in the northern hemisphere. In the east, the relatively star-poor constellations of Pegasus, Capricornus, and Piscis Austrinus are moving into view along with hundreds of galaxies accessible with a small telescope. Also in September, a string of bright planets from Venus in the west to Mars in the southeast remains visible to liven up the sky. Here’s what to see in the night sky this month…

September 1. A lovely array of bright planets has been visible for months now, and September begins with Venus low in the west after sunset along with the bright white star Spica less than a degree away. Moving eastward along the ecliptic you see Jupiter, Saturn, and final Mars in the east or southeast after the Sun sets. Take them all in and enjoy the sight, with or without a telescope.

Sept 1. At magnitude -2.1, the planet Mars continues to dazzle in the southeastern sky after the Sun goes down. As the month begins, Mars is still close enough to Earth to reveal surface detail in a small telescope in steady sky. The dust storms that obscured the surface in July and August have mostly passed, and diligent observers and imagers have reported seeing more detail in good conditions. But don’t wait. The planet will begin speeding away from Earth as September wears on, and its brightness will drop by a factor of two by month’s end.


The rotation of Mars over 2.5 hours on August 17, 2018 as imaged by Niall McNeill from Wattle Flat, NSW, Australia. Niall used a C14 EdgeHD with Tele Vue 2.5x Powermate, a Paramount MX+ mount, and ZWO ASI174MM camera for this capture.

3 Sept. Last Quarter Moon, 2:37 UT.

Sept. 5. Over the next couple of weeks, northern-hemisphere observers who have very dark sky can see the zodiacal light in the eastern sky about 90-120 minutes before sunrise in the northern hemisphere.  This whitish glowing wedge of light appears to thrust upward from the horizon (see image at top of page).  The zodiacal light, sometimes called the “False Dawn”, is simply sunlight reflected off tiny dust particles in the inner solar system.


Four bright planets along the eclipse in early September, 2018. From west to east, look for Venus, Jupiter, Saturn, and Mars. Click to open in a new tab.

Sept. 6. Mercury returns, this time to the morning sky, where it appears today just a finger’s-width north of the bright star Regulus in the constellation Leo in the east-northeast.

7 Sept. Neptune reaches opposition today. This blue-green ice giant, the most distance major planet from the Sun in our solar system, shines at magnitude 7.8 and spans an apparent diameter of 2.4″. Its tiny disk is visible in the constellation Aquarius between the stars Hydor (λ Aquarii) and phi (φ) Aquarii. While the planet is plenty bright enough to see with a telescope, or even binoculars, resolving its disk requires some magnification, at least 75x to 100x. The planet’s disk gets larger with more magnification while the images of the stars do not. Visually, the planet has a very pale blue-green color.


The location of Neptune at opposition in September 2018.

9 Sept. New Moon, 18:01 UT

10 Sept. Saturn reaches its stationary point, and from now onwards it begins its slow prograde motion eastward against the background stars of the constellation Sagittarius. The planet is more than two months past opposition, but it’s still a beautiful sight in a telescope.

13 Sept. A waxing crescent Moon joins Jupiter and the star Alpha Librae (Zubenelgenubi) to form a small equilateral triangle about 4 degrees on each side.

15 Sept. The nearly first-quarter Moon makes an appearance with Jupiter, Saturn, and the star Antares above the southern horizon (and nearly overhead for deep-southern stargazers).

16 Sept. First Quarter Moon, 23:15 UT

19 Sept. The Moon hangs about 4 degrees north of Mars.

21 Sept. Venus reaches its greatest illuminated extent. The planet shines at a shockingly bright magnitude -4.8, as bright as it ever gets. However, the magnificence of the planet is tempered by its relatively low position in the evening twilight over the western horizon. Southern-hemisphere observers will get a better view as the planet appears somewhat higher above the horizon.

23 Sept. The Sun crosses the celestial equator going south at 01:54 UT. That marks the beginning of autumn in the northern hemisphere and spring in the southern hemisphere. At equinox, the Sun is at a point on the ecliptic just west of the star Porrima (gamma Virginis), about halfway between the stars Regulus and Spica.

25 Sept. Full Moon, 2:52 UT

SOURCE: https://cosmicpursuits.com/night-sky-this-month/

9
General Chatty Stuff / Thought for Today!
« on: August 30, 2018, 06:21:59 PM »
On 20 July 1969, Neil Armstrong and Buzz Aldrin landed on the surface of the moon. In the months leading up to their expedition, the Apollo 11 astronauts trained in a remote moon-like desert in the western United States. The area is home to several Native American communities, and there legend – describing an encounter between the astronauts and one of the locals.

One day as they were training, the astronauts came across an old Native American. The man asked them what they were doing there. They replied that they were part of a research expedition that would shortly travel to explore the moon. When the old man heard that, he fell silent for a few moments, and then asked the astronauts if they could do him a favour.

‘What do you want?’ they asked.

‘Well,’ said the old man, ‘the people of my tribe believe that holy spirits live on the moon. I was wondering if you could pass an important message to them from my people.’
‘What’s the message?’ asked the astronauts.

The man uttered something in his tribal language, and then asked the astronauts to repeat it again and again until they had memorised it correctly.

‘What does it mean?’ asked the astronauts.

‘Oh, I cannot tell you. It’s a secret that only our tribe and the moon spirits are allowed to know.’

When they returned to their base, the astronauts searched and searched until they found someone who could speak the tribal language, and asked him to translate the secret message. When they repeated what they had memorised, the translator started to laugh uproariously. When he calmed down, the astronauts asked him what it meant. The man explained that the sentence they had memorised so carefully meant ‘Don’t believe a single word these people are telling you. They have come to steal your lands.’

Sapiens, A Brief History of Humankind – Yuval Noah Harari

10
Our Big NHS Change – Communities’ Voice on Health and Care - SEE DOCUMENTS ATTACHED

We recently undertook a 12-week public consultation ‘Hywel Dda – Our Big NHS Change’, between 19 April and 12 July 2018, into the future of NHS health and care services.  I wish to update you on progress to date and the next steps.

Following the consultation, we have received an independent report, detailing the extent and scope of views received from communities in mid and west Wales. The health board provided many different opportunities for people to voice their views, from completing formal questionnaires and writing in to attending events and face-to-face meetings, as well as debate on social media. This report provides the views of those who chose to respond and highlights some key issues for our Board members to consider as part of their decision-making.

We are publishing that report before it is formally received by the Health Board at an extraordinary meeting, due to be held and webcast from Carmarthenshire County Council’s Chambers on Wednesday, 26 September 2018, where a future service model will be discussed. Making the report available now will allow our patients, staff, stakeholders and communities time to read and consider its contents.

Please read the attached letter for more information about what has been heard and what happens next.

The full report and executive summary are available on the Health Board’s consultation web resource at www.hywelddahb.wales.nhs.uk/hddchange. If you have any issues accessing the report please let us know by emailing Hyweldda.Engagement@wales.nhs.uk or please leave a message on 01554 899056.

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