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September 2009

ASTRONOTES
Incorporating FRIENDS' NEWSLETTER Lost Moons: Apollos 18, 19 and 20 The sky this month Amazing moons of Saturn Messier objects? Tracy clears them up! Hypersonic airships into orbit?

ARMAGHPLANETARIUM


2 Astronotes September 2009

The lost Moonshots
By Colin Johnston, Science Communicator "Project Apollo dominating the `70's like a bloodless war, was to pass into history...After that nothing would ever be the same again. When men raised their eyes to the Moon they would know that their comrades were looking down at them." These words were written by Arthur C. Clarke in 1964 in an early draft of what later became "2001: a Space Odyssey". At the time it seemed a plausible vision of the future. NASA officials and most space buffs expected dozens or more Apollo missions to the Moon in the next decades. However only an insignificant minority of taxpayers were interested in grand space adventures (a fact which is even more true today) and public support for the project faded. As early as 1967 NASA's budget began to shrink as the US struggled to waste money and lives in Vietnam. A mere six months after the triumph of Apollo 11, NASA abandoned its plans for Apollo 20 in January 1970. Worse was to come: Apollos 18 and 19 were officially cancelled in September 1970 because of cuts to NASA's budget for 1971. Public interest in the exploration of another world had dropped sharply with minimal attention paid to Apollo 12. Newspaper editorials were calling for the following flights to be cancelled and the money allocated for them spent to eliminate poverty instead. It is said NASA chiefs were not wholly unhappy with the decision to terminate the lunar missions; the Agency had achieved the goal of landing men on the Moon and returning them, and they feared a fatal accident would eventually occur if the program continued. Losing an Apollo crew might have damaged NASA so severely as to destroy the Agency, ending American manned spaceflight. All three cancelled missions were so-called `Jseries' missions like Apollos 15-17 (Apollo missions were originally planned in lettered series, becoming more ambitious as they proceeded through the alphabet). These missions called for astronauts to stay on the lunar surface for three days or so and make three moonwalks. They would take advantage of improved procedures and technology developed with the experience of the earlier landings, for example on these missions the crews wore upgraded spacesuits permitting greater comfort and mobility and they rolled over the Moon's terrain in Lunar Roving Vehicles to increase the area explored. The last three Apollo missions delivered substantial scientific returns, and one can only speculate on what the cancelled missions would have found. Apollos 18-20 were intended to visit a couple of large impact craters, the hope being that the samples returned would include ancient material from deep inside the Moon. This was expected to be essentially unchanged since the Moon formed. Such material is beyond our reach on Earth. and studying it would have provided a bonanza of data on the early Solar System. Magnificent Moon machine The Lunar Rover Vehicle was developed to allow larger areas of the Moon to be explored. An important character in the story of the lost Apollo missions is astronaut Harrison "Jack" Schmitt (b1935), a professional geologist.

Image Credit: NASA


September 2009 Astronotes 3 Schmitt was one of the `scientist-astronauts' selected in 1965 for their academic and research skills rather than their piloting proficiency. When it became clear that the moonlandings would cease in the mid-1970s, NASA was pressured into ensuring that at least one of these scientists flew on a mission, leading to Schmitt's selection for a place on Apollo 18. Schmitt lobbied for his mission to visit the crater Tsiolkovsky on the lunar farside. This would require a dedicated communication satellite to relay the crew's transmissions to Earth and Schmitt costed the use of surplus Telstars in his proposals. However NASA's management rejected this plan for its expense and greater risk. No human being has yet walked on the Moon's farside.

"Harrison Schmitt was the first scientist to carry out research on another world"
Apollo 18 was intended to take place in July 1973. It would have seen the mission's Commander (CDR) Richard Gordon (a veteran of Apollo 12) and Lunar Module Pilot (LMP) Harrison Schmitt descend to a landing in the crater Gassendi on the northern edge of Mare

Copernicus as photographed by the crew of Apollo 17. This would have been the landing site for Apollo 19 Humorum. Left behind in lunar orbit would have been Command Module Pilot (CMP) Vance Brand. In the event, Schmitt did make it to the Moon despite the cancellation of Apollo 18. He was reassigned to Apollo 17 to explore TaurusLittrow, replacing Joe Engle as LMP on that mission so that a scientist did get to the Moon's surface before the project was terminated. Schmitt was the first and so far only scientist to carry out research on another world. Today, the Apollo-Soyuz Test Project's CSM is occasionally referred to as Apollo 18, but this not correct. Apollo 19 was pencilled in for December 1973. The landing site would have been the floor of the prominent crater Copernicus. The crew would have been Apollo 13's LMP Fred Haise (CDR), William Pogue (CMP) and Gerard Carr (LMP). At the time of its cancellation, a crew had not been selected for Apollo 20. If it had gone ahead in the summer of 1974, the astronauts would have explored the volcanic domes in the Marius Hills on the Oceanus Procellarum, or possibly the rim of the bright crater Tycho. Tycho was considered a slightly risky landing site, and going there would have needed relaxation of some of the rules,

Image Credit: NASA

Apollo's last gleaming Eugene Cernan salutes the US flag during December 1972. He and Schmitt were the last two humans to walk on another world.

Image Credit: NASA


4 Astronotes September 2009 but as a relatively young crater (possibly less than 200 million years old) it was intriguing to geologists. Apollo 20's Saturn 5 was used to place the Skylab space station into orbit in 1973.

"An elaborate hoax has been created around Apollo 20"
Strangely in the past couple of years an elaborate hoax has been created around Apollo 20. Someone calling himself William Rutledge (or sometimes Routledge) claims in telephone interviews with European journalists to have actually flown on this mission as the LMP in August 1976. Launched from Vandenberg AFB in California, this mission was alledgedly commanded by veteran cosmonaut Alexei Leonov while the CMP was a lady called Leona Snyder (who would have been the second woman in space were she not entirely fictitious). "Rutledge" says the secret US-Soviet mission was an exploration of a derelict alien vessel on the farside of the Moon. A lot of work has gone into supporting this fabrication, with includes some nice CGI movies, but it is accepted as fact only by those who prefer fantasy to reality (and, unsurprisingly, this hoax is claimed to be genuine by some who decry Apollos 11-17 as fakes!). The Saturn 5 rockets and Apollo spacecraft
Image Credit: NASA

Jack Schmitt collects samples from TaurusLittrow during the Apollo 17 mission. If history had developed differently he could have done this in Gassendi crater. were already paid for and under construction when their missions were cancelled. The Apollo components became museum exhibits and two of the rockets were transformed into the world's biggest and most expensive lawn ornaments. Alas, despite the premature ending of Apollo, the poor are still with us. After years of training, the disappointed astronauts assigned to these flights retired or were reassigned to the Skylab or Apollo-Soyuz Test Project. Some even flew in the Shuttle in the 1980s. It is hard to believe that some evenings they do not stand in the silvery moonlight and wonder about what might have been. Further reading Clarke, Arthur C, The lost worlds of 2001, Sidgwick and Jackson, London, 1974 Godwin, Robert, Project Apollo: Exploring the Moon, Apogee Books, Canada, 2006 http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_18_20.html

Image Credit: JAXA/Selene

The rim of Tycho imaged by the Kaguya mission (which recently ended when the probe was deliberated crashed into the Moon's surface). In an alternate universe Apollo 20 could have landed there in 1974 (and found that black monolith 27 years early!)

http://www.scientificamerican. com/article.cfm?id=canceledapollo-missions


September 2009 Astronotes 5

The September night sky
by Nigel Farell, Education Support Officer Hello once more everyone and welcome to our regular guide to the night sky set for approximately 11 pm on 15th September. Although we are now beginning to look towards the autumn months the sky is still relatively bright until quite late in the evenings, so you may need to stay up fairly late so that you are able to take best advantage of the September sky. Most of the objects we will discuss this month should require no specialist equipment to observe, however, you will enjoy much more detailed views by using a telescope or binoculars. Remember to give your eyes time to become accustomed to the dark, 10-15 minutes is usually sufficient, and as always we have included a free sky map for your convenience. Galilei (1564-1642) first discovered Jupiter's four largest moons and thus modern astronomers refer to Io, Europa, Ganymede, and Callisto, as the Galilean satellites. When Galileo first made his detailed observations of these moons he noticed that they changed positions and you can recreate his observations when looking at them through a telescope. First find the four moons, record where they are, then if you observe them about an hour later you will notice that they have changed position. Looking towards the constellations, the September sky still contains many of the familiar patterns which we have discussed in previous issues of Astronotes. The Summer Triangle, comprising the constellations of Cygnus the Swan, Lyra the Harp and Aquila the Eagle, is still high in the south eastern sky. Capricornus is still mid sky in the SSW, while the great square of Pegasus is high in the SSE. This month, however, let's focus on some of the constellations which are visible to those of you who have a clearer view of the northern part of the sky. Ursa Major the Great Bear is easily the largest constellation to observe when looking almost directly north. In fact it is the third largest

"Nestled between Castor and Pollux is Mars"
The Moon, rising in the ENE just after 1 am, will be well into its last quarter by the 15th with the new Moon due on the 18th. Rising just before the Moon in the same area of the sky are the Gemini Twins Castor and Pollox. Nestled securely between the two brothers is the planet Mars which is one of two planets visible in the sky at this time of night. The other visible planet is Jupiter, which, sitting on top of the constellation Capricornus, continues to dominate the southwestern sky. Jupiter looks like a very bright star and is easily the brightest object in this region. It is believed that, had Jupiter been about 80 times bigger it would have become a star rather than a planet. Jupiter is a particularly fascinating planet to observe for those who are currently celebrating the International Year of Astronomy (IYA2009). Some 400 years ago the eminent astronomer Galileo

By Jove! Jupiter and the Galilean satellites illustrated in a montage of images from the Voyager spaceprobes. They are not to scale but are in their relative positions.

Image Credit: NASA


6 Astronotes September 2009 constellation in the night sky. However, most people will only recognise the rear and tail of this particular constellation. Made up of seven bright stars and referred to by many names depending on cultural heritage. The Plough, as we call it, is probably the most famous collection of stars, recognisable to even the most casual of stargazers worldwide. In astronomical terms the Plough is referred to as an asterism, a small gathering of easily recognisable stars which usually form part of a much larger constellation. The pattern of the Great Bear, probably more than any other encompasses the myths and legends of almost every culture in the world. The early Welsh and English were said to have linked the constellation to the location of King Arthur's home. In Ireland it was called King David's Chariot which is said to have referred to one of the early Irish kings. The Plough was also said to have been known as the `Farmers Clock' as its tail points eastward in spring and southward in summer thus completing a circle. What a Great Bear! Bears do not usually have long tails but cultures throughout the world see this constellation as a bear. monly repeated tale. Celtic traditions associate this constellation with the god Lugh. In the Celtic calendar Lugh is traditionally believed to be the sun god who dies as the nights draw in after the summer solstice. August was his sacred month celebrated with a festival called Lughnasa known these days as Lammas. In Welsh tradition Perseus is said to represent the great hero Llew Llaw Gyffes. Killed by his wife Blodeuwedd and her lover Gronwy, his soul was transformed into an eagle at the moment of his death. His uncle, Gwydion the magician searched for Llew and found him as the constellation Aquila after travelling across the Milky Way after which Gwydion restored him to life once more and transformed Blodeuwedd into an owl as punishment. That's all for this month, I hope you find our guide useful, and that you enjoy September's stargazing.

"...drops of blood fall from the wound causing the trees to change colour"
The Algonquin Native Americans have a legend which tells of a large mean-spirited old bear, who's favourite pastime was to terrorize a village. Elders from surrounding villages came together and decided to assemble their best warriors to hunt the bear. Unable to escape the warriors the bear eventually ran up into the sky, but was followed by the hunters, who continued to chase him around the North Star. One of the hunter's arrows managed to wound the bear and the legend tells that as the bear and hunters circle low in the sky in autumn a few drops of blood fall from the wound and cause the trees to change colour each year. Another dominant northern constellation in September is that of Perseus. This constellation is particularly well known to those who study ancient Greek mythology. The story of this famous son of Zeus, the king of the gods, and his slaying of the evil Gorgon Medusa is a com-

Moon Phases, Sept 2009
Friday 4 Sept Saturday 12 Sept Friday 18 Sept Saturday 26 Sept FULL MOON Last Quarter NEW MOON First Quarter

Image Credit: www.ianridpath.com/startales


September 2009 Astronotes 7

Two marvellous moons
By Naomi Francey (Editor's note: my pleasure and a privilege to include an article by Naomi in this issue, I am very grateful for her taking the time from her busy schedule to write it. I am sure her many fans will agree!) The International Year of Astronomy hits us again in Armagh Planetarium. On 8 July in our Copernicus hall we had a very well known visitor, Dr Carolyn Porco. Carolyn has been travelling around Ireland as part of a programme in conjunction with the International Year of Astronomy called `She is an Astronomer'. She is an American planetary scientist and is heavily involved with the Cassini probe which left planet Earth in 1999.

"Titan has a thick atmosphere of mostly nitrogen, much like our own atmosphere"
The main focus of Dr Porco's presentation was her true passion, the Cassini probe that went into orbit around Saturn in the summer of 2004. Cassini has brought so many developments and discoveries about our distant neighbour. Before Cassini reached the ringed giant we only had obtained images from the Voyager spacecraft, but Cassini has brought us closer than ever before. The majority of her talk focused on two moons of Saturn, giant Titan and its little brother Enceladus, a moon 1/10 the size of Titan. Titan has long thought to have a possibility of a liquid surface. Astronomers found that Titan has a thick atmosphere of mostly nitrogen, much like our own atmosphere with the additional presence of methane, propane and ethane (and absence of oxygen). Of these gases methane

Dune World? This is a radar image of sand dunes on Titan. In August 2009 it was decided that low-lying plains on Titan would be named after fictional planets from Frank Herbert's series of SF novels which began with `Dune' (1965). and ethane can both be in liquid form at the chilly surface temperatures of Titan. Cassini had taken an amazing photo of Titan backlit with the Sun in which the atmosphere of Titan was clearly visible. When the Huygens probe was released from Cassini on Christmas Day 2004 to descend onto the surface of Titan, it appeared to land on a mudflat that was diffused with liquid methane. The Huygens probe also took images during its descent of what appeared to be a drainage basin and a shoreline. This image was breathtaking and looked like a river system and its tributaries and a mouth where this `river' entered what seems to be a body of water. We could have been looking at the Amazon Basin and the coastline of South America. Also a `desert' was found with dunes over 100 metres in height shown in the image on this page. They also found `lakes' at the polar region. This moon has more similarities to Earth than first expected.

Image Credit: NASA


8 Astronotes September 2009 place on the moon, where jets erupt from fractures in the surface. These jets travel hundreds of miles into space which you can see in the image. Scientists think there could be a possibility the jets could be coming from pockets of liquid water beneath the surface. In this case we are witnessing a geothermal eruption like a geyser that you may find in Rotorua, New Zealand. Image after image left her audience awestruck, these are amazing discoveries that have been made and it is hard to believe that Cassini has travelled the great distance from Earth to Saturn. It definitely proves how capable our species are and the great things that are yet to come. From the viewpoint of a geographer I was amazed at what the Cassini probe had discovered. Saturn's moons are many and these images have showed a likeness to our Earth with drainage basins, coastlines, geysers and dune systems, however they are far from being the life-abundant planet which we live on.

Image Credit: NASA

Enceladus eruptions There is still lively debate among planetary scientists over just how much liquid water exists under this moon's icy surface . Enceladus is an extremely bright moon with a fractured surface. What is most interesting about this bodyis its south pole which is the hottest

Constellations on parade
By Robert Hill, Northern Ireland Space Office Donegal has some of the darkest skies in Europe and for the past few years the Donegal Bay and Blue Stacks Festival has celebrated the darkening nights at the beginning of October with an illuminated carnival parade through the town of Ballyshannon. This year local Donegal company LUXe (the artistic directors of the parade) decided to make a processional spectacle and to develop sculptural work celebrating the launch of World Space Week in Ireland and the International Year of Astronomy. At the launch of their work in Dublin on St Patrick's Day they were awarded the Spirit of the St. Patrick's Day Parade prize. Continuing with this theme throughout the year LUXe proposed theming this year's appropriately timed Ballyshannon parade to celebrate space and astronomy, and in conjunction with the Northern Ireland Space Office and Armagh Planetarium to launch World Space Week in Ireland in Ballyshannon. This will involve combining an existing sculpture on a planetary theme (`The Orrery' , created by LUXe Co-Director, Mark Hill for the Liverpool

Stars in the Carina Nebula a vast, seething glob of dust and gas 7500 light years from Earth.

Image Credit: NASA, ESA and jesus Maiz Apellainiz (Instituto de Andalucie, Spain)


September 2009 Astronotes 9 European Capital of Culture 2008 ) and a cosmic processional spectacle with new and celebratory work, with work from other carnival groups in the region. This will see Ballyshannon's main street and river banks dressed with astronomical imagery in the form of lanternwork, kinetic sculpture, performance, projections and fire drawing. This night of constellations will be the physical climax of an astronomical awareness programme in which "the queen of sciences" is brought into schools and through which the attention of children is drawn not only to the world of astronomy and related scientific activities and possibilities but also to the uniqueness of their dark skies and the rare clarity with which the beauty of the constellations may be enjoyed from Donegal. The children will enjoy visits to the Star Dome (Armagh Planetarium's mobile planetarium), rocket making and designing workshops, cosmic lantern making workshops and a 3D space film presentation. The festival proper will be on the afternoon and evening of Saturday 3 October.

What is a Messier object?
By Tracy McConnell, Education Support Officer Beginners to astronomy will have heard of the term "Messier Catalogue" but may not know what it means or where it came from. The story starts in 1730 with the birth of Charles Messier in the town of Badonviller, Lorraine, France. Messier was born into a wealthy family and was well educated by his father, and after his father's death, his elder brother. At the age of 21, Charles moved to Paris, and entered the employ of Nicholas Delisle. Delisle had been a student of G.D. Cassini, the famous astronomer whose name was given to the Cassini mission to study Saturn and its moons. Nicholas Delisle was the Astronomer of the Navy and young Charles worked with him until 1765 when Delisle retired. This is when Charles took over the position, which he kept throughout his life. As with most astronomers of this time, Charles' time was spent searching for new comets, which were to 18th century astronomers what exoplanets are to today's. Charles Messier discovered thirteen new comets in his 87 year long lifetime and observed 44 others. During his research, Messier noticed a large number of "nebulous" or fuzzy, cloudy objects, which were commonly mistaken for comets. As a result Messier compiled a list containing the details of these objects and his observations of them. This catalogue became known as the "Messier Catalogue of
Image Credit: portrait by Ansiaume

Charles Messier aged 40. Today his catalogue is in common use, his comet discoveries are forgotten. Nebulae and Star Clusters", and each numbered entrant was prefixed with the letter M for Messier, indicating that its designation was listed in the Messier Catalogue. The catalogue was not compiled overnight; in fact it went through several incarnations before becoming the list we know today. The first list containing 45 objects, was published in 1774 in the journal of the French Academy of Sciences in Paris. The final official list, and original version of what we are familiar with today, contained 103 objects and was published in 1781 after a combined effort by Messier and his colleague Pierre MИchain. After its publication Charles Messier added M104 to his personal notes,


10 Astronotes September 2009 indicating that he planned to further revise the list for later re-publication. However Messier was severely injured in a fall in November 1781, he never fully recovered from this accident, greatly hampering his work. When this revision didn't occur, MИchain communicated his observations of M104, M105, M106 and M107 to the Prussian Royal Academy in Berlin for publication. MИchain also reported M108 and M109 as objects which Messier had mentioned in his notes. Messier died in 1817 after suffering many years of illhealth. Today this catalogue contains 110 objects, and today we know a lot more about them due to developments in telescope and optics technology. Some of these objects turned out to be globular clusters of stars. Others are far off galaxies. The term "nebula" is still used today to describe two very different types of object, one being a (potential or actual) stellar nursery cloud and the other being a dying star nebula cloud (a planetary nebula). The Hubble Space Telescope has

Messier 1 the Crab Nebula, a supernova remnant and pulsar wind nebula in the constellation of Taurus. The nebula was first observed by John Bevis in 1731, and was later added to the Messier Catalogue as M1. taken fabulous images of many of the Messier Catalogue objects.

Lightcraft Flight Handbook
Reviewed by Colin Johnston, Science Communicator Saving weight is vital in spacecraft design. Every kilogramme saved from a spacecraft's mass improves its performance. The engines are a heavy component, so why not leave them at home? Power could be transmitted to a space vehicle as a beam of energy, most likely in the form of a laser or microwave beam. This may sound crazy, but some experiments have been performed to prove the concept. In 2000, at a test site in New Mexico, a tiny laser assisted rocket reached an altitude of 71 m (233 ft). Sadly there does not seem to have been any notable development since then, but beamed power propulsion may one day be a regular element of spaceflight. Spacecraft with a lenticular design (that is, shaped like a biconvex lens) were actively studied by NASA and US industry in the late 1950s and early `60s. A craft of such a shape would experience lower heating on re-entry than a winged layout as the heat would be spread over a greater area. A circular design might experience less aerodynamic drag and be more manoeuvrable at subsonic speeds than a winged design. However there were drawbacks; such a craft would be aerodynamically unstable and hard to control. As far as I know no lenticular space vehicle has yet flown (although there is a whole arm of the publishing industry which says such things are being regularly observed). What if these two technologies, beamed power and lenticular aerodynamics, could be combined? Lightcraft Flight Handbook LTI-20 looks at this possibility. The book's authors' credentials are impeccable; Leik N. Myrabo is a physicist with immense experience with beamed power propulsion (he participated in the New Mexico demonstration), while John S. Lewis is a leading

Image Credit: NASA


September 2009 Astronotes 11 planetary scientist. Their book is not the pedestrian look at the state of the art with speculations about the future that you may have expected. Instead it assumes that the US military will in the near-future develop a series of operational `lightcraft' which will be in regular service by 2025. The book is presented as an operator's manual for the lightcraft, an approach adopted to engage the reader according the authors, who stress that the book is not science fiction. Numerous equations, full colour computer-generated images, tables of data, graphs and references show that this is not quite in the same category as, say, a Star Trek Technical Manual. The vehicle envisaged in the book is powered by beams of microwaves generated by facilities in the US. Beams can be relayed by orbiting satellites to avoid the problem of maintaining line of sight to the craft. These beams power three separate propulsion modes; ion propulsion, a magnetohydrodynamic (MDH) system and a pulsed detonation engine (PDE). All three use air as the working fluid so there are no tanks of fuel on board. The ion propulsion system is for silent low speed flight and making the craft ideal for its military missions, including stalking and abducting individuals. To aid its startling performance, the craft is constructed of lightweight materials; a flexible silicon-carbide skin supported by thin structural ribs (I imagine debris from a crashed lightcraft could easily be mistaken for those from a crashed weather balloon). A lightcraft would be an interesting (and possibly alarming) vehicle to observe. It would appear as a mirror-reflective disc in sunlight. In darkness the ion propulsion systems causes the whole vehicle to glow, appearing as a red or orange light from the ground. The microwave-absorbing skin makes the disc invisible to radar. It is pressurized with an oxygen-helium mixture making it neutrally buoyant at sea level and so the silvery disc floats silently in the air even when powered down. When the power is on, its performance is remarkable, capable of prolonged silent hovering and slow flight, the lightcraft can accelerate at up to 200g (the book explains how the crew are protected from this punishment) to orbital velocity. A lightcraft is a hypersonic airship! (A sentence which really deserves more exclamation marks than grammar normally permits.) To protect themselves from stray microwaves, the saucer's-oops! I mean lightcraft's- crew must wear close-fitting black hooded unitards at all times. Only the face is exposed, but even this is covered with a fine metallic mesh `stocking mask' (which I imagine gives the wearer's face a Greyish hue). The eyes are covered with the large oval black lenses of virtual reality goggles... At this point one may begin to suspect that the authors are having a lark with us.... This unusual book from those excellent publishers Apogee can be read on several levels, it may be a very speculative look at future technology (which failed to convince me; apart from some incredible materials which I do not believe are yet available, to get the lightcraft to function you have to assume that suitably manipulated microwaves and magnetic fields can produce just about any effect you want). Alternatively perhaps it is an unusually technical piece of science fiction, or a jeu d'espirt by a pair of renowned scientists. How you chose to look at it is up to the reader. (My thanks to Apogee for the review copy.) Lightcraft Flight Handbook LTI-20 by Leik N. Myrabo and John S. Lewis, Apogee Books, Burlington, Ontario, Canada, 2009

Image Credit: NASA

Flights of fancy NASA examined many layouts for spacecraft in the late 1950s and early `60's. These are the proposed Ames M2-F1, M1-L half-cone and Langley lenticular designs. Of these, only the M2-F1 flew (as a glider rather than a spacecraft).


12 Astronotes September 2009

Image of the Month
Proposed Ames M2-F1, M1-L half-cone, and Langley lenticular bodies.

"Beetlejuice! Beetlejuice! Beetlejuice!" was the chant which summoned the obnoxious ghost played by Michael Keaton in Tim Burton's 1988 movie. Keaton's character was actually named Betelgeuse presumably after the giant star in Orion. This month's image is the best image to date of this huge star, which is roughly 1000 times the diameter of the Sun. Mere millions of years old,Betelgeuse is young compared to the Sun, but is aging badly and is nearing its end. High mass stars live shorter and more dramatic lives than low mass stars. Betelgeuse is in trouble, recent observations suggest it is contracting and

losing material at an alarming rate. Here we can see it is surrounded by a giant glob of gas it has expelled. Were this plume to be superimposed on our Solar System centred on the Sun, it would engulf the planets (Mercury, Venus, Earth, Mars and the Asteroid Belt would be inside Betelgeuse itself!) The brightness of Betelgeuse is variable too, reinforcing that all is not well with the giant star. Betelgeuse will die in an awesome supernova explosion soon. "Soon" here could mean in the next few thousand years. It will leave behind an nebula, similar to the Crab Nebula, with a tiny neutron star at the centre. (Caption by Colin Johnston, Science Communicator)

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Astronotes, Incorporating Friends' Newsletter is published monthly by Armagh Planetarium, College Hill, Armagh, Co. Armagh BT61 9DB Tel: 02837 523689 Email: cj@armaghplanet.com Editor: Colin Johnston ©2009 Armagh Planetarium All rights reserved

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