7. Nebula November 2016 v44_2

Nebula

October 2016 Newsletter of the Leeds Astronomical Society
Volume 44 Number 2

INTERSTELLAR TRAVEL WITHIN OUR LIFETIMES? – MAYBE!

by Chris West

It sounds absolutely incredible, I Artist’s impression of nearest exoplanet, Proxima Ce ntauri b (ESO)
didn’t quite believe it myself at the
time of reading about it on the ple of centuries, to the nearest which a huge scoop would collect
BBC Science and Nature website, stars to our Solar System. E.E.Doc the diffuse hydrogen in interstellar
but, it’s true! There are plans to Smith popularised the idea of the space, ‘burn it on the fly’ using a
send a multitude of ‘nano probes’ interstellar drive, which could uti- proton-proton chain reaction, and
fitted with scientific data recording lise a fictional device named hy- expel it out of the back. This craft
and observational equipment to perspace, allowing starships to could, theoretically, accelerate to
Proxima Centauri at a velocity of jump from one star system to an- near the speed of light, thus mak-
around 20% of the speed of light other within seconds and circum- ing use of time dilation effects in
sometime in the 2030s. After a 20 venting the limitations imposed by order to shorten the duration of
year journey, the probes would the speed of light limit within journeys to other stars for any fu-
reach the Proxima system and start normal space. By the 1940s and ture, intrepid, interstellar explor-
collecting spectrographic and bio- 50s, later, younger science fiction ers.
chemical data of Proxima and any writers such as Isaac Asimov, Ar-
planetary bodies in orbit around thur C. Clarke and Brian Aldiss Alpha Centauri lies at a distance
the star. carried forward and developed the of 4.37 light years. It consists of
idea of whole galactic societies, three stars; the pair Alpha Centauri
But, first, a bit of background in- made possible by starships star- A and Alpha Centauri B, and a
formation on humanity’s dreams to hopping through this weird hyper- small, faint, red dwarf, Proxima
reach other star systems from our space. Centauri, that may be gravitation-
own Solar System. A few philos- ally bound to the other two stars.
ophers and intellectuals since the In the 1960s, propulsion experts Alpha Centauri A has 110% of the
Middle Ages have speculated that like Dr Robert Bussard in the U.S. mass and 151.9% of the luminosity
there was an infinitude of stars like proposed what was named the of the Sun, and Alpha Centauri B
our Sun out there in deep space, Bussard Ramjet, a fusion rocket in is smaller and cooler at 90.7% of
such as Nicholas of Cusa, who
lived in the 15th Century. In time,
the distances of some of the stars
began to be worked out more pre-
cisely than in earlier times. By the
19th Century, the first stellar paral-
laxes were accurately worked out.
With the coming of the 20th Centu-
ry, rocket engineers and propulsion
experts began to take very serious-
ly the possibility of humans
launching starships, within a cou-

President’s piece page 3 Blast from the Past page 7 The Sun page 10
Galactic Mergers page 4
Inside … Pluto’s Name page 6 Passage of Ti me page 8 Solar System Cycling page 11

‘Big History’ page 9 Observi ng Reports page 13

N EB UL A VOLUME 44 I ssue 2 PAGE 2

Solar mass and 44.5% of Solar about the year 2060. However, at cestral home planet, to colonise
visual luminosity. During the the present moment in time, and explore other worlds in other
pair’s 79.91 year orbit about a Breakthrough Starshot is still very star systems. We may learn an
common centre, the distance be- much in the early planning stage, incredible amount about how our
tween them varies from about that and there’s a real possibility that Sun and its attendant planets
between Pluto and the Sun, to that either the costs involved will be formed, originally. We may, also,
between Saturn and the Sun. too prohibitive, or that the probes discover strange, new life forms
Proxima Centauri is at the slightly may meet with an unforeseen acci- which would keep scientists busy
smaller distance of 4.24 light years dent in deep interstellar space. for centuries to come. It’s all got
from our Sun, making it the closest Still, it seems to be well worth giv- to be, definitely, worthwhile.
star to our Solar System, though ing the project the best start possi-
not visible to the naked eye. An ble, and the benefits, scientifically, HOW TO GET TO OUR
Earth-sized exoplanet in the habit- could be stupendous and compe l- MEET INGS
able zone of Proxima Centauri has ling.
been detected, and as far as I Carlton Hill,
know, has been scientifically veri- There’s no doubt, in my opinion, Friends Meeting House,
fied as actually existing, the results that manned interstellar travel 188, Woodhouse Lane,
were recently published in Nature. won’t be taking place any time Lee ds
This planet may be a destination of soon. Some physicists and engi- LS2 9DX
future interstellar spacecraft, in- neers don’t think that it will ever
cluding the afore-mentioned nano prove possible, or feasible, to Directions from Woodhouse
probes currently being developed launch vessels that may well be Lane :
for a fly-by mission by the Break- vast in size and even more in terms
through Starshot Project. of expense. To send a team of By car, turn into St. Mark's
humans to even the nearest stars street there is a small car park
Many other future space craft for would utterly bankrupt the global on the right.
travelling to and between the stars economy within the economic pa-
have been envisaged over the last rameters of the present time, and it From Headingley, the bus
50 years, such as so-called Genera- may well prove politically impos- stop is just after you pass the
tion Starships or Space Arks, in sible for governments to sell to the meeting house
which whole generations live and tax-payers the idea of funding a
die on board the giant craft on dec- few humans to the stars, even By foot: 25 mins uphill going
ades or centuries-long journeys to though the benefits may not be felt out of town to the University.
other stars. Putting the astronauts by people on Earth for centuries to
into deep sleep by means of ad- come. Nevertheless, my guess is By bus: all buses to the uni-
vanced cryonics have also been that within the next couple of cen- versity: 1,28,56,93,95,96,97.
speculated upon and proposed. turies, the first manned star ships From the city centre ask for the
But Breakthrough Starshot is an will be blasting off from our an- stop outside the Chemical Engi-
audacious attempt to send a series neering Dept, the stop afte r the
of nano-probes the size of fairly LOCATION MAP Parkinson Building Steps.
large computer chips to the
Proxima System. The project was
launched in April, this year, and
will be initially funded by the Rus-
sian billionaire, Yuri Milner, and is
being endorsed by Professor Ste-
phen Hawking, Mark Zuckerberg
and Kip Thorne. According to
Milner, ‘if the Voyager spacecraft
had left our planet when humans
first left Africa, travelling at 11
miles a second, it would be arriv-
ing at Alpha Centauri just about
now’. By contrast, if the nano
probes set off some time in the
2030s, after a 20 year journey,
they should be in a position to start
sending data from Proxima round

N EB UL A VOLUME 44 I ssue 2 PAGE 3

PRESIDENT'S PIECE

On my study wall is an old Jewish by David Leyshon mous people who have greatly ad-
saying: ‘We don't see things as they mired the Meditations. Okay, don't
are; we see them as We are’. What what’s ‘up’ there only occurs when ask me whether Clinton always lived
does that mean? Does it refer to our they are doing something else. Work- by those maxims. AND please don't
emotions? Our intellect? Our mental ing nights for examp le—perhaps just ask what Donald Trump’s favourite
state? Or what? walking home after a n ight in the pub. book is. I refuse to be drawn on that
one!
Whatever it means, we don’t just I’ve been reading the Meditations of
see things - we interpret them. Ho w Marcus Aurelius. In case you’re Anyway, one night in Germany—
does this relate to astronomy? Well, wondering who he was, he was a Ro- maybe it was this time of year and
tonight I watched the Last Night of the man empero r who ru led fro m A D 161 chilly—Marcus Aurelius wrote these
Proms but, before the concert started, to 180. He featured in the film Gladi- words: ‘The Pythagoreans [an ancient
I went outside to show my third ator, played by the late Richard Har- school of philosophy founded by Py-
grandchild the moon and the summer ris. Marcus Aurelius believed that the thagoras] tell us to look at the stars at
triangle. It was a b it chilly - dare I use office of emperor obliged him to be daybreak. To remind ourselves how
that word yet? - so we hastily ret reated moral in private life and to be diligent they complete the tasks assigned
in d o o rs . in his public duties, not to use being them—always the same tasks, the
emperor to indulge himself or harm same way. And their order, purity,
Of course it’s September, the month others, as some other emperors like nakedness. Stars wear no conceal-
of transitions, of beginnings and end- Nero did. Whilst campaigning against ment.’
ings. The end of summer—one author German ic tribes, Marcus kept a diary,
describes it thus: ‘... September deliv- containing philosophical musings —it Okay, these words don’t sound too
ers the last day of summer’. Time to was something to do at night, espe- scientific. Do the stars have ‘tasks’ to
go back to work (in earnest); the start cially as he sounds a bit of a loner. complete? And perhaps his thoughts
of school and college terms; a hint of These became the famous Medita- on astronomy were second-hand, alt-
coldness in the air, that dreaded time tions. hough he must have gone outside at
when Christ mas cards appear in the some time to actually look at the
s h ops .... Bill Clinton is one of the many fa- heavens. But does it really matter?
The stars—he believed—give us les-
It’s also the month of the Autumnal sons on how to live our lives. We
Equino x, dark nights, the approach of might say that his deeply-held convic-
winter. There’s a mood of foreboding tions led him to think of them in that
mingled with anticipation. way.

Back to astronomy. I’ve mentioned And should that surprise us? As
in previous pieces the different ways humans, we do more than just look at
people ‘do’ astronomy, as well as the things. We study them, investigate
reasons that motivate them. For some them, analyse them, even derive les-
people, astronomy is a lifelong pas- sons for life fro m them.
sion—for others it’s a sudden awaken-
ing, and for some an awareness of And so those wise words I began
with apply to astronomy par excel-
lence: ‘We don't see things as they
are; we see them as WE are ’.

Something to reflect upon, as you
stand outside in the cold winter
months contemplating the heavens.

Happy contemplating!

SUBMISSIONS

Submissions of material for Nebu-
la from members are welcome—as
are comments, suggestions and
letters. Items should preferably be
emailed to the editor. Contributors
please note that we place copies of
the journal (in PDF format) on our
website

N EB UL A VOLUME 44 I ssue 2 PAGE 4

GALAXY MERGERS much ‘galaxy fuel’ to feed on. A
well known example of such a
by Gerry Leake supergalaxy is M87 in the constel-

Edwin Hubble convincingly ues to ‘eat’ small dwarf galaxies lation of Virgo. This has a black
showed in the 1920's that the Uni- that approach too close, and that hole at its centre of 6.8 billion
verse was expanding and that on at the present moment the dwarf solar masses, which is over 1,000
the largest scales everything was galaxy in Sagittarius is being times more massive than the black
moving away from each other. pulled apart and will be absorbed hole at the centre of the Milky
However, at the same time, it was into the Milky Way in the near Way. Whew!!

found that at smaller scales in the future (astronomically speaking).

Universe, namely at the scale of But ‘this is what galaxies do— Colliding Spiral Galaxies of Arp 274
Local Galaxy Clusters, this was they eat their friends if they get Credit: NASA, ESA, M. Livio (STScI)
not happening. Gravity, instead, too close’, and this cannibalism
reigned supreme and the result can result in some of the largest and the Hubble Heritage Team
was galaxies coming together. As and most energetic galaxies that
we all know, the two largest gal- we know of—the supergiant ellip- (STScI/AURA)
axies in our Local Group— tical galaxies with massive black
Andromeda and the Milky Way— holes at their centres. These su-
are on a collision course and will pergiant elliptical galaxies are of-
make contact in about 4 billion ten found at the centres of dense
years. galaxy clusters, and this has ena-
bled them to grow to such large
I have always been interested in sizes because of the closeness to
galaxy collisions and this interest the centre of such clusters of
was awakened by a recent article

that I came across. There it was

proposed that galaxy collisions MEMBERSHIP SUBSCRIPTIONS
were probably the principal way

in which the many small The following subscriptions are due at the beginning of each calendar year:
protogalaxies in the early Uni-
verse became, by mergers, the Full Membership: £25 Reduced Rate: £15
normal galaxies that we observe
First Year Membership: £10 Institution Membership: £25

today. Indeed the article stated The reduced rate is applicable to junior members of 17 years of age or less,
full-time students, registered disabled, senior citizens over 65 years and
that the Milky Way galaxy may members who are unemployed when subscription is due. The institution
have formed ‘from as many as rate is applicable for groups or schools and includes membership for one
adult and 15 juniors.
100 protogalaxies as a result of
galactic mergers’. In addition we

know that the Milky Way contin-

.

Meetings programme 2016

Feb 10 Dr. Michael Martin-Smith (HERAS), Asteroids, armaggedon or Eldorado?
Mar 9 Prof. Andreas Friese (Birmingham University), Shining a Light on Black Holes
Apr 13 David Sellers (LAS), William Gascoigne of Leeds and the Renaissance of Astronomy
May 11 Gareth Powell (Met Office. Exeter), Forecasting the impacts of space weather
Jun 8 Dr. Katherine Johnston (Leeds University), Unravelling massive star birth with ALMA
Jul 13 Tim Old (HERAS), New horizons, Pluto and beyond
Aug No meeting
Sep 14 Dr. Matthias Willbold (Manchester), The accretion of the Earth - Moon system
Oct 12 Dr Ken Amor (Oxford University), Chelyabinsk meteor
Nov 9 Prof. Sam Falle (Leeds University), Relativistic jets
Dec 14 President’s Evening

LEEDS ASTROMEET

Saturday 12th November 2016
Clothworkers’ Hall, Leeds Unive rsity (doors open 9 a.m., start 10 a.m.)

A whole day of Astronomical talks, exhibitions, slide show s and stalls.

N EB UL A VOLUME 44 I ssue 2 PAGE 5

KEEP IN TOUCH Leeds Astronomical Society
First Founded 1859
HOW TO JOIN THE LAS CHAT GROUP Regi stered Charity 1101539

by Robin Jakeways Affiliated to British Astronomical
Association
In your favourite search engine, Go to Accounts.
type "Yahoo Groups”. Affiliated to the Federation of
Click your new Yahoo email Astronomical Societies
Click on The Yahoo Groups web address under Yahoo or
site. Primary Yahoo. Website:

Type Leeds Astronomical Socie- Make sure that Forward is se- www.leedsastronomy.org.uk
ty in the box saying “search lected under Access your
groups” and click on Search Yahoo Mail elsewhere OFFICERS AND COMMITTEE
Groups. The LAS site will appear.
Enter your preferred email ad- President
Double click on it and then click dress to which you want David Leyshon
“+ Join Group" posting to go over Forward-
ing Address Vice President
You now have to set up a new Chris West
Yahoo email account. Previously Select Store and Forward
you could use any account but they Hon Treasurer
have recently changed the rules. Click Save Danny Parsonson

So you need a Yahoo name and a You will get an email asking Secretary
password. you to verify your email ad- John Herbert
dress.
To set the Yahoo account up you Visiting Speakers Coordinator
have to fill in your life history (not You should now be done. It will Andy West
quite but what they require is in- be worthwhile going into the ya-
trusive and not necessary!). They hoo account from time to time to Public Relations Officer
also require a moblile phone num- clean it up otherwise the mail box Robert Lewis
ber so if you haven’t got one you may show full at some time!
are stuck! Very silly. Observing Coordinator
If you still have a problem email Robin Carmichael
Having filled in all the boxes and me at
got rapped over the knuckles once [email protected] Hon Librarian
or twice for not completing a box Kevin Taylor
you click on create account. WHERE?
Instruments Coordinator
Yahoo will then send me a mes- The sun was shining on the sea, John Herbert
sage asking me either to accept or Shining with all his might:
reject. LAS members are accept- He did his very best to make Ordinary Committee Members
ed, outsiders are not. The billows smooth and bright-- Joanna Bialek
And this was odd, because it was Steve Kirk
The annoying feature about the The middle of the night.
new system is that postings will Ast/meet Speakers Coordinator
only go to your new Yahoo ad- The moon was shining sulkily,
dress. Because she thought the sun Website Coordinator
Had got no business to be there Mick Rose
I have now discovered how to After the day was done—
automatically forward LAS emails “It's very rude of him,” she said, Email Group Coordinator
to your usual email address so that “To come and spoil the fun!” Robin Jakeways
you don’t have to go into Yahoo
every time you want to read the The Walrus and The Carpenter Auditor
postings. Proceed as follows: byLewis Carroll, ‘Through the David Leyshon
Looking-Glass and What Alice
Go into your Yahoo mail ac- Found There’,1872) EDITOR
count.
David Sellers
Click the gear icon near to the Da vid.Selle rs@ ntl wo rld.com
top right hand corner. A
menu will appear.

Select Settings.

N EB UL A VOLUME 44 I ssue 2 PAGE 6

PLUTO – HOW IT GOT ITS NAME
by Gerry Leake

Pluto and its moons have re- PLUTO -- July 14, 2015 from New Horizons when the s pacecraft was 280,000
ceived considerable media atten- miles (450,000 kilometers) away, show features as small as 2.2 kilometers)
tion during the last few months © NASA / Johns Hopkins University Applied Physics Laboratory / Southwest
since the flyby of the New Hori- Research Institute
zons spacecraft last July. Although
it was relegated to the status of a covery there were numerous sug- and to the Royal Astronomical So-
dwarf planet by the International gestions as to what its name should ciety that this name be given it. As
Astronomical Union (IAU) in be. “One of the suggestions came far as we know Pluto was first
2006, Pluto has continued to en- from Venetia Burney, a schoolgirl suggested by Miss Venetia Burney,
gage the fascination of the public. from England who enjoyed learn- aged 11, of Oxford, England.”
Indeed many professional astron- ing about mythological characters.
omers (and amateur) still consider On the morning of March 14 while I should, perhaps, add that Vene-
that it should never have been de- Venetia ate breakfast, her grandfa- tia was not the only person to sug-
moted in the first place. ther read to her a newspaper ac- gest the name, Pluto, but she ap-
count of the planet's recent discov- pears to have been the first
As we all know Pluto was dis- ery. After thinking about the news
covered by Clyde Tombaugh in and reflecting on her knowledge of Venetia Burney, aged 11, c.1929
1930 at the Lowell Observatory in mythology, she said Pluto, the god (image: Wikimedia)
the USA. Initially it was referred of the distant cold underworld, was
to simply as Planet X. So how did an appropriate name for this dark
it get its name? and gloomy place. Her grandfather
sent her suggestion, unknown to
I came across an article in the Venetia, to the British astronomer
March 2016 issue of the American H. H. Turner, who in turn shared it
magazine Astronomy which out- with Lowell Observatory.
lined the history surrounding the
naming of the (now) dwarf planet. “This note would be one of hun-
The following information has dreds received by the Observatory
been taken from that article. but stands alone in importance , as
indicated in the last paragraph of
As can be readily appreciated, the May 1 Lowell Observatory
after the announcement of its dis- Circular that served as Pluto's
christening announcement to plan-
Leeds AS member, Prof. H.H. et Earth. Lowell Director Vesto
Turner, 1929 (picture from the Melvin (V.M.) Slipher wrote [my
italics], It seems time now that this
Society’s Scrapbook) body should be given a name of its
own. …Pluto seems very appro-
priate and we are proposing to the
American Astronomical Society

N EB UL A VOLUME 44 I ssue 2 PAGE 7

Cartoon by Andy West, inspired by the above extract from an article on The Eye in Observing, which ap-
peared in the Report and Transactions of Leeds Astronomical Society (No. 2, 1894)

N EB UL A VOLUME 44 I ssue 2 PAGE 8

THE PASSAGE OF TIME

by Melvyn Taylor

The oldest timepiece seen was those long gone times meant that grounding in physics. Often the
some years ago in Salisbury Ca- somehow water clocks were con- ongoing work on cosmic-rays done
thedral, a wrought-iron mecha- structed. (A fascinating piece of by teams at Haverah Park, outside
nism, not easily recognized, in the wet-engineering may be seen in St. Harrogate, was up-dated by the
north aisle. This was created for Mary Redcliffe Church in Bristol. Physics Dept.
the purpose of pulling and sound- It is called the Chaotic Pendulum
ing a bell(s) thus identifying the and was devised and installed by a But returning to time, sundials
various daily activities for the learned and very clever team in are very attractive for aesthetics
monks and clergy. It was probably 1997). and practical purposes and recently
made by specialists on the Europe- I saw a catalogue of saleable items.
an continent (France or the Nether- On the passage of time, 1965 It was obvious from images of the-
lands perhaps) and a similar inven- was when I joined the LAS at the se that most did not have the ap-
tion is in Wells and Windsor. recommendation of a land- propriate angle of the gnomon
surveyor in the old West Riding even for southern or high northern
This ‘bell-clock’ may have been County Council’s architects’ de- UK latitudes. And back to Salis-
connected with Salisbury’s origi- partment. In 2009 when we cele- bury, the attached photograph tak-
nal magnificent bell tower in the brated the 150th year of its found- en in 2005 shows an appropriate
14th century but in 1792 the tower ing a thoughtful soul and friend ‘starry’ feature on this dial located
was demolished. The ‘bell-clock’ pointed out the 44 years represent- on a wall under the eaves of a
was ‘lost’ until 1926 and was duly ed about 30% of its history. Meet- house in Fisherton Street.
restored by the Cathedral authori- ings were held in the Mathematics
ty. Basically a weighted mass cre- Dept of the University and the air
ates the gravity to drive the es- was distinctly academic: Dr. Robin
capement, a truly ingenious piece Jakeways could be consulted on
of technology for its age, which aspects of these meetings but two
then transfers a horizontal shaft to talks duly stick in my memory.
force a bell rope. One was about the 98-inch mirror
for the Isaac Newton telescope that
Medieval time measurement in was being proposed and the speak-
many places, notably Italy and er showed how tests were to be
France, had a bell tower and/or a done. One blow of a timber mallet
simple dial that only defined hour- on it would reveal any fissures that
ly changes. I suppose we have to could make it unusable. This ac-
thank ancient Babylonian astron- tion proved correct (!). Then there
omers/astrologers for the modern was a demonstration using radar
hours of a day, who divided the (in the lecture room) on the detec-
heavenly zodiac into 12 bits. And a tion of meteors - it went over my
remarkable attitude to water in head even though I had had a

The Salisbury Medieval Clock

N EB UL A VOLUME 44 I ssue 2 PAGE 9

Have you heard of something called BIG HISTORY Big History in 2mins
Big History? http://www.snotr.com/video/9884/
by Chris Oddy Our_history_in_2_minutes
Big History is our story, starting
fro m just after the Big Bang 13.81 ties). If there is sufficient interest we TED talk by David Christian, who
billion years ago, travelling across could have the first course trial in the coined the name “Big History”
different timescales and disciplines new year and take it fro m there. If
tracing our history. It is older than the anyone in the Leeds Astronomy So- www.ted.com/talk s/david_christian
written word and takes in the cosmos, ciety and/or readers of Nebula are _big_history?language=en
Earth, life and humanity. interested please let me know what
your thoughts are (via email A 1991 artic le on where Big History
My name is Chris Oddy and, to- [email protected] m) comes fro m: The Case for “Big Histo-
gether with Rick Rogers , I would like ry”, by David Christian, Macquarie
to introduce you to this subject. We In time the three courses we are Un iv ers ity
are trying to put together an education looking at organising are:-
and local interest package on Big His- http://www.uhpress.hawaii.edu/jou
tory. We would like to include local A one off course/lecture giving us rnals/jwh/jwh022p223.pdf
groups and organisations as we pro- Leeds’ 13.8 billion year story ahead
g ress . of Leeds’ bid for European City of International Big History Associa-
Culture 2023. tion
Big History Leeds is looking at set-
ting up a multi-subject course based An eight part course based on the http://www.ibhanet.org/
on Cosmology, Earth Science, Natural Big History Project (we can use
History and Humanities among others. their online facilit ies). The aim is to The Big History Project
We also aim to give the course a local give Big History a Yo rkshire slant. bighistoryproject.com
slant and add something of ourselves
to this wonderful story. A fuller course with depth to it for Big History Institute, Macquaire Uni-
anyone wanting to take this subject v ers ity
As regards to education, in the short further.
term Rick Rogers recently gave two http://bighistory.mq.edu.au/
talks in Leeds as an introduction to The content would be down to the
Big History. These took place on: people involved in the process of cre- Big History European Network
ating the course. It would be great if http://bighistory.eu
i) Friday September 16th , 1152 Club, you could help Rick with a few ideas
Kirkstall Abbey House as regards to content on the Cosmolo- Big History UK
gy/Astronomy side of things. Rick http://bighistory.org.uk/
ii) Friday October 7th, Sociable His- Rogers main area is History, not Cos-
tory Club, City Museum mo logy, Earth Science, Geology, Nat- Big History Leeds
ural History etc so there would be http://www.bighistoryleeds.co.uk /
Beyond that we would like to put serious scope for local groups and
together a course on Big History but organisations to make their mark. Facebook
with a Leeds/Yorkshire slant to it. We http://m.facebook .com/BigHistory
could base it around The Big History Please let me know what you think. Leeds?
Project (we can use their online facili-
Finally, if you would like to know Twitter
more about Big History (and have https://mobile.twitter.com/bighisto
access to the Internet), please check ryleeds
the references below.

A ti meline of the Big History Project "Threshol ds" as presented on the B HP website

N EB UL A VOLUME 44 I ssue 2 PAGE 10

THE SUN: OUR AMAZING STAR

by Chris West

Our nearest star, the Sun, is by Hertzsprung-Russell Diagram: an important tool for determining
far the most important source of how stars evolve (image: NASA/GSFC)
energy for life on Earth. Its di-
ameter is about 109 times that of ants choose to remain here on our ly, divinity for the Pharaoh Akhe-
the Earth, and its mass is about planet. naton. Other cultures, including
330,000 times that of Earth, whilst the Hindu, Japanese and Aztec,
accounting for about 99.86% of The English proper noun, Sun, had a rich tradition of Sun wor-
the total mass of the Solar System. developed from Old English, ship.
About three quarters of the Sun’s Sunne, and may be related to,
mass consists of hydrogen, the rest South. Similarities to English, Coming back to the present, of
is mostly helium, with much ‘Sun’, appear in other Germanic course there is almost an infinity
smaller quantities of heavier ele- languages, including Old Frisian, of other stars – about 200 billion in
ments, including oxygen, carbon, Sunne, Old Saxon, Sunna, Middle our Galaxy, alone. But that bril-
neon and iron. Dutch, Sonne, modern Dutch, Zon, liant, yellow/orange ball of ionized
and modern German, Sonne. The gas in our skies cannot help but
The Sun is a G-type main- English weekday, Sunday, stems have a special place in our hearts
sequence star, (G2V), based on from Old English, Sunnandaeg, and minds, in our science, litera-
spectral classification, and it is “Sun’s day”, from before A.D. ture and mythologies. Our Sun
informally referred to as a yellow 700, and is, ultimately, a result of a sustains all life on our planet, as
dwarf by astrophysicists. It Germanic interpretation of Latin well as driving our weather and
formed approximately 4.6 billion dies solis, itself a translation from climatic systems. By studying our
years ago from the gravitational Greek. The Egyptians worshipped Sun, we will, in addition, learn
collapse of matter within a region the sun god, Ra, from at least the much more about the other stars,
of a large molecular cloud. Most 4th Dynasty of Ancient Egypt. In and vice versa. Our Sun is an end-
of this matter gathered in the cen- the form of the Sun disc, Aten, the lessly fascinating object of study in
tre, whereas the rest flattened into Sun enjoyed a brief resurgence its own right, and the future will
an orbiting disc that became, even- during the Amarna Period, when it have much, much more light to
tually, the Solar System that we became the preeminent, if not on- shed, pardon the pun, on our clos-
know today. The central mass be- est star.
came increasingly hot and dense,
due to the effects of gravity, even-
tually initiating nuclear fusion in
its core. The consensus among
astrophysicists is that all stars form
through this process.

The Sun is middle-aged, and has
not changed dramatically for over
4 billion years, and will remain
fairly stable for a further 5 billion
years. However, after hydrogen
fusion in its core is shut off, the
Sun will start to fuse helium to
carbon, and will undergo severe
changes and become a red giant. It
is calculated that the Sun will
eventually become sufficiently
large and bloated as to engulf the
current orbits of Mercury, Venus
and possibly Earth. The star which
sustains all life on Earth will, ulti-
mately, destroy all life, including
humanity, should our far descend-

N EB UL A VOLUME 44 I ssue 2 PAGE 11

CYCLE THE SOLAR SYSTEM

by Kevin Taylor

The Sun (2.42 m diameter) Shortly after leaving Pluto I Route Map (by permission of Physics
heard a POP-HISSssss noise from Outreach, University of York)
On the 29th of May 2016, Vad, the rear end of my bike. Of course
Eva (aged 6), Nadine and I, went I didn’t really need to look to Sometime after Uranus we came
on a bike ride down a disused part know what had happened. Not be- across a large contraption on a
of the old East Coast main-line ing a very good scout, I wasn’t pole fitted with a satellite dish. A
railway. The route (near York), prepared. Fortunately Vad had a sign read that it was a 1/3rd scale
from Riccall to Bishopthorpe cov- puncture repair kit with him (He model of the Cassini probe. We
ers 6.4 miles. What’s special is also offered to ride back to his car
that spread along the route is a and get a spare inner tube. In the
scale model of our Solar System. spirit of space travel I decided con-
The planets along the route are in tinue with what we had). The
scale (100 metres of track equals puncture was caused by my tyre
57 million kilometres of space) being worn right through to the
both in their relative sizes and dis- inner-tube. Therefore, once re-
tances from one another. This paired, I could only pump the tire
equates to the speed of light to be up with enough pressure to stop
about 1.16 mph, making cycling the rims running on the track—
about 10 times light speed. This otherwise the inner-tube ballooned
scale would also put Alpha Cen- out of the hole. I had to hope that it
tauri one and three quarter times lasted for the rest of the journey,
around the Earth away! One of giving a little “Apollo 13” feel to
Alpha Centauri stars—Proxima the ride!
Centauri—has been in the recent
news with regards to a potentially One thing about the distance
earth sized planet in the habitable scale that was really apparent (you
zone. All of these facts and more can look up the facts and figures,
can be found on the model’s web- but it doesn’t compare to the ex-
site, https://www.york.ac.uk/solar/ perience of leg power) was just
how far away Pluto was from the
rest of the planets. If it hadn’t been
for the incredible images from last
year’s New Horizons photos, one
could be forgiven for going along
with the new planetary definitions
to disqualify Pluto (hopefully this
will be reverted).

Kevin, Vad and Eva with the Earth and Moon on the cycleway

N EB UL A VOLUME 44 I ssue 2 PAGE 12

knew, therefore, that Saturn must Eva and Saturn (20.22 cm diameter)
close by. It was only a few yards
away, slightly obscured by foliage. The Sun was located just by the we can detect the gravitational
To Eva, Saturn with its rings was A64 flyover. The planets’ scale wobble of planets that are as far
like a ship’s wheel. away from their star (that is many
and distance from it made them light years away from us) as de-
Jupiter came by very quickly. picted by this model is hard to
Pluto, by comparison is tiny. seem pretty much insignificant. To comprehend.

Mars, Earth, Venus and Mercury think that with modern instruments
were so little a bike ride after that
as to almost seem to be on top of
one another. Also their sizes had
shrunk back down again. It’s very
evident when seeing these scale
models like this that the bulk of the
planetary mass is pretty much just
Saturn and Jupiter.

The ride was easy going and
good for Eva, at just her second
proper bike ride. For those without
a bike, or the means to transport
one, it is possible to hire a bike
from York train station.

WHY I LOVE THE SKY DURING THE SUMMER MONTHS

by Robert Lewis (reflecting on the summer)

I always love the summer sky at treme Northern latitudes, in particular If you haven’t gone to bed and
night. It’s early July and I love the the Arctic Circle. Here the sun does maybe wandering in fro m the pub or
way the sun only sits just below the not set and remains above the horizon simp ly happening to be looking at the
horizon and its rays are still to be seen at certain times of the year. night sky through your window take
around 11 p m and midnight. The sky time to ponder this phenomenon. The
does not assume its inky darkness like The sun is geometrically below the sun is still there, not quite asleep in
it does in winter. In Leeds, Yorkshire, horizon in what could be called night twilight of its own.
we are at a rather northern latitude. according to the time but astronomical
Beyond the city lights, just above the twilight and/or civil twilight, accord- £96m investment in Engi-
horizon, the redness of the evening ing to what imp inges on the senses. neering & Physical Sciences
sky is still present and the sky above Light rays are still passing through the
that is a beautiful light- to mid-b lue. Earth’s atmosphere and being refract- at University
The rays of the sun are still impinging ed back to the observer. The blue af-
on the sky. It’s wonderful. I never ter-glow in the sky is remarkab le be- Leeds University has approved
observed the sky to be so bright at that cause the sun is not present like during plans to create an international
time of night in Northampton. In the day or the sun set event. It’s as if Centre for Engineering and Phys i-
Somerset and Devon, the sky is darker the sun is still illu minating the sky by cal Sciences on the north eastern
still and the stars appear to be brighter proxy. The sun constantly transmits its part of campus. The £96m project
and more nu merous there. rays (obviously) and those that im- was approved by the University's
pinge on the atmosphere get scattered governing body in Oct 2016. It is
“Just look at the big sky”, sang Kate equally in all direct ions by the mole- the largest, single-project invest-
Bush in one of her songs. Some stars cules of nitrogen and oxygen, giving ment ever to have been made on
are still quite bright and diagonally that blue colour. campus.
above me I could see Ursa Major, one
of my main reference points in the While looking at the horizon I am of The new Centre will bring to-
night sky. It’s the phenomenon at the course scanning for noctilucent clouds gether schools of Engineering,
lower altitude that interests me at this which are not frequently present. Computing and Physics & Astron-
particular time. It is reminiscent of the Their high altitude reflects sun light. omy. Works should be completed
Midnight Sun that occurs at the ex- One supposes that if you were at that by 2020.
height you would still see the sun.

N EB UL A VOLUME 44 I ssue 2 PAGE 13

OBSERVING REPORTS

IC1396 CEPHEUS IC1396 in Cepheus

Imaged by Ray Emery M57 The Ring Nebula
Imaged by Rod Levene
Imaged on 05/Oct/2016.
Telescope: Televue Genesis This image of M57 (2/Sep/2016)
100mm aperture f5 apo refractor is from my garden.
(old Petzval design).
Camera: Canon 700D (modified) It was from just 6 exposures at
with Astronomik clip-in CLS fil- 30 sec. The short time was because
ter. of uncertain tracking/ align-
Mount: Skywatcher EQ6, perma- ment and even with this, I dis-
nently mounted. carded 3 frames. I used a 'Nebular'
No autoguiding. filter and I suppose I should have
Exposures: 10 x 6 mins @ ISO repeated it without, but didn't have
1600 time. The processing is all about
Darks & Flats. detail versus background noise, so
Stacking: Deep Sky Stacker. you’ll find that the sky isn’t black.
Processing: Gimp. I see it’s also robbed the stars of
Since there were so few images, I their colours. I use my 8" Newto-
didn’t worry about any feint satel- nian and a Sony camera which,
lite trails for this one! despite having ‘live view’, focuses
with difficulty. I also did a run of
M57 The Ring Nebula 10 sec exposures which resulted in
more noise if the detail was to be
brought out. Neither try revealed
the central star but at mag. 14.5,
that’s not surprising.

The object is 2.5' of arc wide and
you can see that it’s not a perfect
circle. Astronomers now think that
it’s not spherical but we are look-
ing at a bit of an angle into the end
of a cylinder, shaped by its mag-
netic field.

N EB UL A VOLUME 44 I ssue 2 PAGE 14

M101, M97 & M108 M101 The Pinwheel Galaxy

Imaged by Kevin Taylor tonian. It’s fitted with a Baader and an Astronomik CLS EOS clip
Mark-III coma corrector, and filter fitted. Image processing was
Here are 2 pictures from the New mounted on a guided Sky-Watcher done using MaximDL and GIMP
Inn last spring. HEQ5 pro. The camera, a Canon 2.9.3.
1100D, has its IR filter removed
M101 The Pinwheel Galaxy (im-
aged on 30/Apr/2016) is compiled
from 10 x 9 Minute, ISO800 Expo-
sures.

I suspect the galaxy is feint be-
cause of the filter I used. However,
not using one isn’t an option so close
to Leeds’ city lights. Many distant
galaxies can also be seen in this pho-
to when see in its original form on a
computer screen.

The Owl nebula & the Surfboard
Galaxy (imaged on 30/Mar/2016) is
compiled from 9 x 8 Minute, ISO800
Exposures.

I’ve never managed to see the owl
Nebula, despite looking at it through
the eyepiece of several telescopes.

Both pictures were imaged through
my Celestron Omni XLT 150 New-

The Owl nebula & the Surfboard Galaxy