OCTOBER 2012 ISSUE
Asteroid Imp
acts Pages
t Nig a y k S Th e
ht
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Planetary Geology A three part special on Planetary Geology from our geology expert Emma Quinlan
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EDITORIAL
Editor: Chloe Partridge Copy Editor: Martin Griffiths Contributors: Emma Quinlan, Helen Usher, Terence Murphy Columnists: Phill Wallace, Martin Griffiths
Welcome back to another academic year of Glam UNIverse. I have no doubt that this year will be filled with even more interesting articles and feature stories. To kick off the start of another great year we have a three part Planetary Geology special from our geology expert Emma Quinlan. Emma has an amazing depth of knowledge and passion when it comes to geology and she has cleverly crafted a series of articles to talk us through Planetary Geology, which we can look forward to over the coming months. In this months issue, as usual we have our death and destruction themed article from Phill Wallace, and The Sky at Night by Martin Griffiths—two articles which are always a joy to read—as well as a tantalising article on Red Dwarfs by Terence Murphy.
If you would like to contribute in any way, either by sending us your Faulkes images, or perhaps even writing an article , then get in touch, we would love to hear from you. Editorial Contacts : 10017607@glam.ac.uk mgriffi8@glam.ac.uk
Some Observational Astronomy students have also been taking part in STEM ( Science, Technology, Engineering and Maths) based teaching work shops, in local schools, and Helen Usher has written a lovely account of her time introducing the Sun and our Solar System to kids, in a fun and engaging environment. Interesting science all round… PS. For all the newbie Astronomers joining us, welcome aboard the thought train that is BSc Observational Astronomy… get stuck in.
IMAGE REFERENCES: PG 1. Tharsis Tholus — geochristian.wordpress.com PG 4-5. City Earthquake — www.pureanimegallery.com, Tidal wave — end-2012.com, Fireball — www.wikipedia.org, Acid rain — www.gasdetection.com PG 6-7. The Grand Canyon. - www.camperscircle.com, The surface of Venus - www.our-earth.net, The surface of Mercury. - discovermagazine.com, The Martian sedimentary landscape - www.seasky.org PG 8-9. All images Martin Griffiths, Sky Map — Heavensabove.com PG 10. Pair of red dwarfs, Gliese 623 A and the tiny B.—C. Barbieri (Univ. of Padua), NASA, ESA PG 11. Student, - herald.thehoweschool.org/ PG12. Newton — www.splung.com
GLMAORGAN ASTRONOMY
OCTOBER 2012 ISSUE
CO SMO LO G ICA L
NEW S
4-5. ASTEROID IMPACTS—OR, HOW WE’RE ALL ROYALLY DONE FOR.
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W E A L L K N OW A S TE R OI D I M P A C TS A R E A BA D T H I N G , B U T I T TU R N S O U T TH E Y ' R E A LO T W OR S E THA N W E TH O U G H T. R EA D ON TO FIND OUT W HY...
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6-7. ROCK TYPES - SEDIMENTARY. EVER HEA RD GEOLOGY B EING LA BELLED A S BORING? WE HOPE TO P ROVE Y OU W RONG ! GE TTIN G UP C L OSE A ND P E RS ONA L W I TH P LA NE T EA R TH’S R OC K TYP ES WE A RE FINA LLY A TTE M P TIN G TO U N D E R S TA N D O U R P LA NE TA R Y S I B L I N G S A N D H OW TH E I R M A KE UP DIFFERS FROM OURS.
8-9. THE NIGHT SKY IN OCTOBER. W ITH A U TUM N N IG H TS D RA W ING IN , W HA T IS VIS IB LE IN THE OC TOB E R S KY? A ROUN D UP OF P LA NE TS M E TE O R S HOWE RS A ND P OI N TS O F I N TE R E S T.
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10. RED DWARF STARS AND THEIR INTERESTING NATURE.
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RE D DWA RFS A RE UNJ US TL Y C ONS IDE RE D B Y MA NY TO B E SMA LL, RE D, C OOL , INA CTIV E A ND UN IN TE RES TIN G B E CA USE THE Y A RE SLOW DEVELOPERS.
11. AN ADVENTURE WITH A GOLF BALL, A TOILET ROLL...AND 130 KIDS. A DA Y IN THE LIFE OF S TE M A MBA SSA DOR HE L E N US HER A S SHE HELPED OUT A T HEOLDDU COMPREHENSIVE SCHOOL'S SCIENCE WEEK.
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COSMOLOGICAL NEWS
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Tokyo Earthquake
Asteroid Impacts – Or, how we’re all royally done for! We’ve all seen Armageddon. Those of us with
probably caused by one or more impacts in the thousand years and compress that all into one
more taste have seen Deep Impact. We know
Yucatan region. A piece of rock just six miles or blast. If that impact happened, every single
that a big rock from space hitting Earth is a
so across wiped out a majority of species on
living thing within 3700 km would be
bad thing. Fortunately, in films there’s always
Earth. That’s staggering.
incinerated. That’s going to be a big insurance
Bruce Willis in a dirty spacesuit to save the day with a nuke and a heroic sacrifice, or something similar. Sadly, we live in the real world not fiction, and there are plenty of big old rocks tumbling through space.
But it gets worse. Let’s take an example
bill.
asteroid and work out the damage potential. If
Despite this massive damage potential, it’s a
we assume a 30 km wide mostly silicon
common belief that asteroids do damage on a
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asteroid with a density of 2700kgm , moving at global scale solely through loading the a 25 kms-1 velocity (fairly typical for Earth-
atmosphere with dust and ash and blocking out
Luckily, no known large rock is going to hit us
crossing objects), this asteroid would strike
the sun, inhibiting photosynthesis and wiping
within a thousand years or so, no need to
the surface with a kinetic energy equivalent to
out the food chain. Now, that does happen, and
worry. But we know that rocks have hit Earth in around three billion megatons. To put this in
it is bad. But impact events have eight other
the past. The Cretaceous-Tertiary Event, which perspective, imagine detonating a nuclear
distinct damage mechanisms:
rendered the dinosaurs extinct, was most
bomb like Little Boy every second for six
OCTOBER 2012 ISSUE
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Ballistic Impact Ejecta: Any impact will launch upper atmosphere, this column could contain 10 wake, making it more elongated than a nuclear debris upwards on ballistic paths from the
to 30 times the impactor’s mass in water,
blast.
impact site. Most of this debris is launched
humidifying the upper atmosphere. We’re not
upwards into space, where it will eventually fall
quite sure what effect this would have, but it’s
Wake Radiation: A massive hypervelocity
back to Earth, resulting in lots of smaller
unlikely to be beneficial. Cloud particles forming
impacts, although these hardly matter after a
may reflect sunlight, which is bad, or cause a
really big impact. There is another, related
runaway greenhouse effect, which is also bad.
problem however. The passage of so much
Tsunami: The second-most-famous mechanism, gasses behind it. This wake can be modelled as a
hypervelocity debris up and down through the
impactor passing through the atmosphere will generate an enormous bow wave of superheated and ionised gas in front of it and will also leave a wake of superheated expanding
especially for smaller impacts. A large ocean
columnar explosion with similar effects to a
impact generates a massive wave that will
nuclear blast; shockwaves and intense thermal
sweep across the seas until it hits land, finally
radiation. Moreover, the nature of the fireball
breaking tens or hundreds of miles inshore.
means the thermal radiation will be propagating
Particularly dangerous to humans since we
through the upper atmosphere which is pretty
build next to the sea. In case of an impact
much transparent to thermal radiation,
Water Injection: An impactor can carry a
tsunami, getting some sea air is not good for
resulting in much more widespread effects.
massive column of water and steam into the
you at all.
Impact earthquake: It’s a massive
Acid Rain: Passing through the atmosphere at
hammerblow from space; of course there will be
these speeds generates shockwaves that allow
seismic activity. Massive shockwaves
chemical reactions to create massive amounts
propagating through the crust would create a
of Nitrous Oxide, which will fall as acid rain
vast area of destruction, far larger than the
atmosphere will generate massive friction, heating the upper atmosphere (transparent, remember, so the heat will spread easily). A really big impact will heat the atmosphere above 1500K, which is enough to sterilise the planet.
thousands of miles from the impact site. The NO fireball radius. This is particularly dangerous to will also destroy the ozone layer and would take human civilisation due to our habit of building many decades to be “scrubbed” from the air by large scale structures and sensitive facilities Tidal wave
natural processes.
such as nuclear plants, chemical storage
Electrodynamic interactions: A lot of ionised
facilities and so on.
stuff is moving around after an impact and this
Suffice to say, an asteroid impact on a large
ionic jet will interact with Earth’s magnetic field scale is a total game changer. Anything on a
Impact fireball
to create a giant generator, altering the shape
massive scale will annihilate all life on Earth.
of the magnetosphere and converting some of
Any small impact will devastate whole
the jet’s kinetic energy into thermal energy in
continents and end human civilisation, if not
the atmosphere (as if it needed more heat after existence. an impact). This will destroy the ozone layer and probably disrupt the van Allen belts, which would probably be bad.
Impact Fireball: Exactly what it sounds like. The impact will release massive amounts of kinetic energy in the form of heat, superheating the surrounding atmosphere and blasting it outwards in the same way a nuke does, although Acid rain forest
the fireball will be drawn up into the ionised
BY PHIL WALLACE
COSMOLOGICAL NEWS
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Rock Types - Sedimentary Let’s bring this back to basics. Geology is the science of rocks and how rocks function to form the planet we know as Earth. I love geology, plain and simple. I will never cease tiring of learning about our fascinating planet and how she works. The most dog-eared subject of Geology is undoubtedly rock types. I can hear a collective groan amongst my fellow students as they sleepily listen to another lecture on rock formation. Bear with me, there is light at the end of the tunnel. The rock types of Earth are diverse and complex. Their most amazing feature is their variety. Rocks are composed of many different minerals, volatiles and crystals depending on how and where they have been formed within the Earth. Understanding these rock types gives us a great insight into our own planet and also the surfaces of the many other planets which litter our solar nursery. There are three main rock types, Sedimentary, Metamorphic and Igneous. So, shall we start with the most basic; Sedimentary? Sedimentary rocks are created through the process of erosion of surface rocks on a
planet. Erosional processes can be fluvial (water/river) or aeolian (wind) in nature. For sedimentary rocks to form, erosional processes must take place to breakdown the existing bedrock. The composition of planetary bedrock in its original state is usually igneous rock. This is due to how the planet forms and cools leaving a solidified igneous crust. However, on Earth erosional processes continually recycle the bedrock through the rock cycle and therefore the bedrock can also be sedimentary rock. Through the methods of erosion, previously formed rock gets beaten and weathered until they are no more than just sand and grit. These sediments are layered on top of one another where they are compacted by their combined weight and pressure to form sedimentary rocks. These rocks are unique as they have not been affected by internal heat and pressure, unlike metamorphic and igneous. The terrestrial planets all have weathering processes by which they can recycle their bedrock. However, can the terrestrial planets actually form sedimentary rocks through these processes and can we see this in action? The only erosional process which takes place on the innermost terrestrial planet is aeolian. Mercury suffers from extreme solar battering
Earth’s greatest sedimentary feature, The Grand Canyon.
The surface of Mercury. The bedrock has been eroded away. due to its closeness to the Sun and its weak atmosphere, which results from a weak magnetosphere. Throughout the formation of the solar system and up until now, Mercury has had to defend itself from extreme solar winds and coronal mass ejections (CME’s), which strip the planet of its bedrock. This makes Mercury an uninhabitable planet. It also restricts the types of rocks that can form on Mercury. It is safe to say that Mercury possesses none of the erosional requirements to create sedimentary rock and the likelihood of there being any type of this rock is extremely slim.
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OCTOBER 2012 ISSUE
Venus, our nearest neighbour possesses aeolian and fluvial processes. The presence of a thick and dense atmosphere that can create huge weather systems indicates a high possibility of erosion and deposition. Although this all sounds promising, if someone were to actually go there, sedimentary rocks would not be found. The makeup and composition of Venus’ atmosphere is so corrosive that
The surface of Venus. Corrosion of igneous rocks or sedimentary?
sediments and dirt would not be able to survive. The last terrestrial planet is Mars. Mars is the
atmospheres current state of expansion and
Sulphuric rain and strong winds has corroded
right distance away from the Sun to escape the contraction it is unlikely that Mars is producing
the surface of the planet. Rock cannot form
heavy bombardment that Mercury obtains
when an atmosphere destroys its chances of
however it does share a weak atmosphere. The
forming. Another rock type is present on this
atmosphere of Mars expands and contracts,
planet where sedimentary rock cannot form.
making it more susceptible to CME’s and solar
Our own planet is the third terrestrial planet in the solar system. Earth has the right processes of erosion such as an atmosphere, rivers and weather systems which allows a very diverse range of sedimentary rocks to exist. The most common Sedimentary rock is Limestone. Distinctions between sedimentary rocks are based on their strata (layers) and their granular sizes. Granular sizes can be from a grain of sand up towards a 2cm pebble. The larger the matrix, the more conglomerate the sedimentary rock is. Erosion takes place within rivers, coastal areas and by aeolian environments such as deserts. Due to our steady atmosphere sediment layers can build up and over time can produce stratigraphic layers of sedimentary rock.
flares. Unlike Mercury and Venus, Mars possesses polar ice caps which keep water locked frozen for most of the year. When these ice caps melt, the erosion which takes place is fluvial. The abrasion of bedrock takes place by
To recap, Mercury and Venus are not and never were stable enough to produce sedimentary rocks. The only planet other than Earth to produce sedimentary rocks is Mars. The likelihood is that Mars is slowly losing the ability to produce these rocks due to its weak atmosphere.
broken glaciers moving in their warmer migration in the summer months. The melt from I hope you have enjoyed learning about the first and most basic rock type. The journey is to these glaciers produce liquid water that cuts be continued … into the bedrock eroding channels into the surface. The larger conglomerates are steadily eroded by the fast flowing water and by abrasion. We can determine that near the polar ice caps Mars could produce sediments which could form into sedimentary rocks. On the main body of Mars weather systems produce aeolian erosion. Huge dust storms are violently swept across the land due to the recession of the atmosphere. These wind systems pick up small and large sediments within their bowls, transporting them worldwide across the planet. Abrasion also takes place in these wind tunnels when the sediments and sand is intermingled and collides together. In the past with a stable atmosphere which was constant, Mars was able
The Martian sedimentary landscape.
new sedimentary rocks.
to produce sedimentary rocks. However, in the
BY EMMA QUINLAN
COSMOLOGICAL NEWS
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The Night Sky in October October sees the last of the summer constellations dominating the sky and the rise of the Autumn constellations of pegasus, Persues and Andromeda, along with the barely discernible groups of Aquarius, Cetus and Pisces. The Orionid meteor shower, associated with the debris of Halley’s comet may give a reasonable showing – weather permitting.
Moon In October:
The sky in October: The sky as it would appear at 22:00 on the 1st
nd
First quarter: 22 October Full: 29th October Last Quarter: 8th October New: 15 th October
Planets in October Mercury: is low in the pre-dawn sky and is close to Saturn on the 6 th of the Month. It is moving toward inferior conjunction with the Sun. Venus: Is a brilliant morning object located amongst the stars of Leo and shining at magni- Jupiter: Is in Taurus and is tude -3.9. The planet is just a tenth of a degree wonderfully bright, shining from Regulus on the 3rd October at magnitude -2.3 and almost visible all night, Mars: is in the constellation of Libra and is very rising a short time after sunset. The moon is Uranus: is still located in Pisces and is an close to the sun still after sunset so little ob- only 1 degree south of the planet on the 5th of evening object shining at magnitude 5.7 after its opposition earlier this year. It should be servation of this enigmatic planet can be made the month. visible as a distinctly green white ball with this month as it is very low on the SW horizon. Saturn: is in conjunction with the sun on the 25th October and is not well placed for observa- moderate magnification. tion this month.
Constellation of the month: Cetus Cetus is the largest constellation in terms of area in the Autumn sky, and is an amorphous collection of faint stars that mark the boundaries of the fabled "Sea Monster" that was sent to attack the beautiful Andromeda to compensate for the boasting of her mother, queen Cassiopeia. Thankfully, the hero Perseus was on hand just in time to save the fair maiden. He killed the sea monster by showing it the decapitated head of the Gorgon Medusa, thus turning Cetus into stone. Poseidon incensed that his monster was dead, then placed it in the sky, in a position where it could still threaten Andromeda, and roar its disapproval at Perseus. On old star maps, Cetus
is always portrayed as a whale, with huge teeth and frightful appearance, which belies the nature of these gentle creatures. Big, was obviously not always beautiful to the ancients.
Neptune: Is an evening object in Aquarius with a magnitude of 7.9. A high magnification should reveal a small blueish ball of light.
casual observer, but unfortunately, its low altitude as seen from Britain tends to water down the brilliance of some of them and adds one or two magnitudes to others. Identifying the group is not difficult; simply look for the head of the Cetus contains a few objects of interest to the monster, which is the most easterly part of the constellation. Its 5 stars mark out a round outline from which it is relatively easy to figure out the rest of the constellation as it spreads south and westwards. Cetus contains the beautiful variable star "Mira", the typical object of this type of celestial wonder, in addition to several galaxies that lie within the range of amateur telescopes.
OCTOBER 2012 ISSUE
The best deep sky object in Cetus is the Sb type spiral galaxy M 77, a tenth magnitude smudge of light just under the "chin" of the monster. It is not an easy object in binoculars, but it may be seen on a good night as a faint glowing mass of grey light 60 million light years away. M 77 is a very unusual galaxy, one of the closest of a type known as "Seyferts", after the astronomer Carl Seyfert who made a study of their ultraviolet excess and their violent nuclei in the 1940's.
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Omicron Ceti, or Mira as it is commonly known. have lost a lot of dust and gas during formation as angular momentum propelled material away This name was given to the star by Hevelius, from the formative nebulae, so it could have and it was the only variable star known for planets similar to those of our solar system. No quite some period of time. The name means telescope yet built will show these planets however, so we will have to await any reply to our radio "Wonderful", and many observers will agree signals to confirm their presence. As yet no one that it deserves its name. Mira can be seen on has answered. any Autumn night even when at minimum as it varies between magnitude 4 and magnitude 9 in a period of 331 days.
Seyfert galaxies are mostly spiral types characterised by very bright nuclei in proportion to their spiral arms, and also the peculiar presence of emission lines in their spectra. Further study of these galaxies has revealed that there is a tremendous amount of energy flowing out of the core of these objects, originating from a very small space at the centre. They are also radio galaxies, and some are also visible in both x-rays and ultraviolet light, evidence of intense activity, the source of which is postulated to be a Black Hole. Astronomers think that a black hole of several million solar masses is shredding stars and gas within these galactic nuclei, and ejecting some of it into space where it collides with the interstellar and intergalactic medium, creating a shock wave which causes such intense radiation. Seyfert galaxies are thus related to radio galaxies and Quasars, being a little lower down the energy scale. Galaxies worth seeking out are NGC 157 and NGC 908, two galaxies with a magnitude of 11, so don’t expect to see them that well as in a small telescope they will merely be little
On occasion, Mira becomes a lot brighter; during the late eighties the star was a brilliant naked eye object shining at second magnitude, and transformed the Autumn sky with its incredible orange glow that was plain to see. The spectral type is M, and the distance is roughly 220 light years, which is relatively close for such a star. Over 4000 Mira type long period variables are known, most of which have periods between 250 and 400 days, thus making convenient distance indicators, as most of these giant stars have a similar intrinsic luminosity. Mira is a very large star, probably around 300 times the diameter of our Sun, and one of only three stars in which spectral bands of water vapour have been found. At minima, the star switches most of its energy output into the infrared part of the spectrum as it becomes an intense red colour and the surface temperature drops to only 1800 degrees Kelvin. Its oscillations can be followed in binoculars or a small telescope and is an ideal object to introduce the amateur to the vagaries of variable star observing.
smudges of light, and all but invisible in binoculars. NGC 157 is an Sc type spiral lying 65 mil-
One star of interest within Cetus is the third magnitude TauNebula Ceti. It is not a binary system or M57 The Ring variable, but is a G type star of almost the same gated in a low power eyepiece. NGC 908 is an dimension and luminosity as our Sun. Tau Ceti is Sc type spiral at a similar distance to NGC 157 only 11 light years away, and due to its Sun like and is a little fainter than it. Both galaxies these qualities was picked as a target for the SETI procan be viewed but their arms will be a dull haze gramme, the search for extraterrestrial life. It is with a faint core. The flagship of the constella- not known if Tau Ceti has a planetary system, but all the evidence points to it being a single star, tion is of course the beautiful red giant star which according to the rules of physics, must
One system that does have planets however is a magnitude 6.7 star just to the west of g Ceti. This system, HD 16141 is a GIV type system with one planet with a mass of 30% that of Jupiter orbiting the star in 75 days at a distance of 0.36 AU. The star and its attendant plant is just over 100 LY away and will require binoculars to spot the star, although this is les difficult that other systems due to the dearth of stars in this area of the Autumn sky. Another extrasolar planetary system is that of HD 19994, right on the Cetus / Eridanus border. The star is an F8V spectral type lying 70 LY away and visible on The Sky and Sky Atlas 2000. The planetary system has just one known body with a mass twice that of Jupiter orbiting at 1.3 AU from the star with a period of 454 days. The coordinates are RA 03h 12m 46s Dec -01 11m 45s and the magnitude is 5.1, making this a naked eye object and an easy star to spot in binoculars. Cetus contains little else of interest to the observer with modest equipment, although owners of large telescopes will have a red letter day with the dozens of galaxies visible in this area, most of which are around 12th magnitude and are good candidates for the scrutiny of the supernova patrol. Browsing through a good star atlas will give their positions against the star of this large constellation.
lion light years away, which looks a little elon-
BY MARTIN GRIFFITHS
COSMOLOGICAL NEWS
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Red Dwarf stars and their interesting nature The classification of stars into different types was started toward the end of the 19th Century and persisted through until the beginning of the 20th when Annie Jump Cannon at Harvard rearranged the previous nomenclature so as to produce the basic Harvard Classification System still used today. Stars were grouped into sections that were distinguished by their surface temperature, although this was not known until some time later. The Harvard groups are O B A F G K and M. So O type stars have a surface temperature above that of about 33,000 Kelvin whilst M stars have a temperature below about 3,700 Kelvin. Stars with such surface temperatures can be comparatively big as per Red Giants, or comparatively small as in Red Dwarfs. The spectral lines observed in their light easily distinguishes between the two. The determination of a Stars mass and volume is still quite a difficult problem and the fact that we know these parameters for as many stars as we do is a testament to the ingenuity, intelligence and persistence of generations of astronomers. So, we now know that there are very many red dwarfs in our own galaxy and presumably in other galaxies too. The prime difficulty in observing red dwarfs is that they are small, cool and hence dim. The absolute magnitude of Proxima is +15.5 and at a distance of 4.2 light years its apparent magnitude is +11.1, much too dim to be seen without optical aid. An M5.5 red dwarf like Proxima Centauri has a mass some 12% that of the Sun and a radius some 14% of the Sun. The radius scales to the volume in a cubed fashion so that Proxima has a volume only 1.5 times that of Jupiter. This tells us that the density of Proxima is something like 40 times that of the Sun. This is primarily because the gravity of the ma-
Pair of red dwarfs, Gliese 623 A and the terial in the star balances the energy outflow tiny B. from the fairly low level of thermonuclear reactions in the core at a point where its density is this value. Another problem is that the closer the planet is to the star the more likely it is that the planet The escape of heat energy in M-type red dwarfs will be tidally-locked into an orbit that is in a 1 : 1 is interesting too. ratio with its spin or in a 3 : 2 ratio like Mercury The forces and temperatures involved result in is with the Sun. the whole body of the star undergoing convec- In either case the radiation from the star protive movement unlike stars like the sun where duces areas of heating on the planet that will only the outer layers undergo convection. find it difficult to dissipate heat in a requisite This convective motion results in the Helium time resulting in permanent or slow-moving product of Hydrogen fusion being mixed-in and hotspots that would not be conducive to life. swept away from the core. New Hydrogen then Small stars that are dense and fully convective replaces this Helium and the core continues its produce magnetic fields that are proportionately fusion as if no Helium had been produced. One greater in magnitude than larger stars. This consequence of this mixing is that no build-up of results in magnetic outbursts or flares that can Helium will occur. Between this and the fact that be unpredictable in time and duration and that Hydrogen fusion proceeds at a slow rate the encompass the full spectrum from radio waves lifetime of an M-type dwarf is very long indeed. to x-rays. On Proxima these flares can increase The actual lifetime of Proxima will be somethe stars luminosity by a full magnitude (i.e. 2.5 where between 1000 and 4000 billion years. times). Such large and fast changes present The Universe is only 13.7 billion years old so another challenge to life. according to this every red dwarf that has ever formed will still be out there. This does not inAll of these possible problems will not stop us clude red dwarfs that are in very close binary investigating red dwarfs. There are so many of partnerships with other stars where massthem and, being small, the radial velocity method transfer or merger has or will take place. for planet detection works so very well. No wonder then, that we find red dwarfs wher- Red dwarfs do have planets and we will find ever we look, to the limit of observability. them in large numbers. There is so much to learn that I can hardly wait. It has been estimated that 80% of the stars in the Milky Way are red dwarfs and if we want to find lots of planets around stars then we need to TERENCE MURPHY look closely at red dwarfs. The great quest is to find Earth-like planets in the so-called Goldilocks zone. One of the problems with habitable planets around small stars is that the smaller the star the closer in and narrower is the habitable zone. The narrower the zone the less likely it is that a habitable planet will be found there.
OCTOBER 2012 ISSUE
Page 11
An adventure with a golf ball, a toilet roll...and 130 kids One of the reasons I signed up to the Observa-
afraid that expecting kids to sit still for an hour
which was a relief. The majority were clearly
tional Astronomy Course (as a mature student)
while being lectured by a novice was unlikely to
interested and asked really good questions. I
was to get involved in outreach/schools work.
be that inspiring or memorable. So more goog- was most worried about the questions I'd get
So when the STEM newsletter asked for volun-
ling for help with activities. I was looking for
teers to help out with a science week at my local ways of getting over the scale and distances
asked as kids seem to retain facts so much better than people of my age, but thankfully I
comprehensive school I offered my services.
involved. So, the golf ball was used as the earth could answer all but one. They also liked getting
The science week was in June so I thought that
and I asked the class to estimate how big the
doing some demonstrations with some solar
sun would be on the same scale - the answer as The teachers were also very interested, and I
scopes would be appropriate and fun. The head
it turned out was about the size of the class-
of science thought this was a good idea and I
room - and how many earths would fit in the sun them to use in the future. The feedback was that
popped up one morning to show her what I had
(its about a million for reference). Then to dis-
in mind. We set up in the yard at the centre of
tances. I'd seen a few ideas for setting up in the
the school and the teacher enjoyed looking and
school playground, and I'm sure it would have
seeing sunspots and flares (first success!). The been fun, but lashing rain and 30 kids didn't curiosity of staff and pupils alike soon became
really appeal to me. So instead there was a
apparent as people loitered as they passed to
toilet roll! This worked well for a couple of rea-
see what was going on... and we gave a few
sons. Firstly it really got the pupils' curiosity
more their first view of the solar disk, to lots of when they walked into the class to see me rolloohs and aahs (second success!). So a full day
ing up a toilet roll (a first for them I think).
involved and I was never short of volunteers. provided some extra background materials for everyone had thoroughly enjoyed it. What did I learn? When I first stood in front of a lab full of 30 13-year-olds I remembered why I'd decided to be an accountant rather than a teacher! But as I got into the swing of it I remembered why I now wanted to get involved, as I really enjoyed seeing the kids getting inspired by astronomy.
planned for the Friday. I borrowed scopes and
Secondly, it got a lot of them involved as I need- The plan is go back to the school when the ed one per planet and the sun. The scale for the weather permits and set up the scopes in the
mounts from Martin to supplement my equip-
distance was that one sheet of toilet paper was
ment and briefed the lab assistants at the
the distance between the sun and mercury.
of solar viewing and associated activities was
school for their role in ensuring safety. So Thursday night was spent putting together a Plan B for how to entertain and inspire 5 forms of (about 30) 12-14 year olds for an hour each in a classroom. The teacher gave me a lead by saying that they'd be interested in the solar system. So after some hours of googling and re -reading my planetary science course notes (thanks Paul!) I had a presentation with animation on the solar system. Good, but....I was
playground again. And I'm hoping to be there
again in Science Week next year - hopefully with
They unrolled the toilet roll around the class and rather better weather..... stood at the relative positions of the planets marked by names on the toilet roll. The kids were clustered at the front close to the sun, while poor Pluto (left in despite of its demotion) was in the far back corner looking pretty lonely! (We did need a few bits of sellotape to repair the solar system during the day as I must admit I didn't use the 'soft and strong' brand). How did it go? The pupils got really engaged,
BY HELEN USHER
I can calculate the motion of heavenly bodies, but not the madness of people. -Isaac Newton
BSc (Hons) Observational Astronomy