WADHURST ASTRONOMICAL SOCIETY

APRIL NEWSLETTER 2006

INDEX: MEETINGS, OTHER NEWS, CONTACTS

MEETINGS

COMMITTEE MEETING

      Members of the Committee are reminded that there will be a meeting of the Wadhurst Astronomical Society Committee at 2000 on Monday 10th April 2006 at the Abergavenny Arms in Frant.

      Any member of the Society is always welcome to come along to the committee meetings and join us over a pint.

THE MARCH MEETING  

Great Astronomical Blunders

Talk given by Martin Frey at the Society meeting on Wednesday 15th March 2006

    This evening's talk was given by Martin Frey from the Homewood and District Astronomical Society near Appledore.  He said they usually meet in a convenient pub.

      As we were to see, there have been very many blunders made in the history of Astronomy and as an introduction Martin began his talk by referring to a number of blunders made during the discovery of the planet Neptune - and also some lucky coincidences.

      In 1781 John Herschel had discovered Uranus, the seventh planet from the Sun, and in 1841 a young and brilliant mathematician undergraduate at Cambridge University, detected irregularities in the movement of Uranus.  This mathematician was John Couch Adams from Cornwall and he calculated the accurate position of a yet undiscovered planet that could possibly be causing these perturbations.  He showed his results to the Director of Cambridge Observatory, professor James Challis who was impressed and gave Adams a letter of introduction to take to George Airy, the Astronomer Royal at Greenwich.  Martin regarded this as the first blunder to be covered in his talk because Adams had an awkward and shy personality.  He wasn't able to see Airy who was having his dinner at three in the afternoon, something Adams regarded as a put-down, but left his notes and returned home.

      Airy then wrote to Adams asking if he had made allowance for the Radius Vector of Saturn.  Another blunder was the fact that Adams thought this too trivial a question and never replied.  A further blunder was caused by the fact that neither Challis nor Airy communicated Adams' notes to anyone and finally Neptune was discovered by a German astronomer using calculations made by a French mathematician called Le Verrier.  These were the same as calculations made earlier by Adams. Yet instead of feeling cheated, Adams congratulated Le Verrier and they became friends.

      Because of this friendship, both Adams and Le Verrier together attended a conference in Washington, USA, in 1884 to decide the internationally agreed Prime Meridian where with Adam's persuasion, Airy's transit line at Greenwich became recognised as the World's standard.

      Returning to the discovery of Neptune, Martin pointed out that a year earlier or a year later and the relative positions of the two planets would have been further apart and the perturbations would have been far smaller and would not have resulted in the discovery of Neptune at that time.  Another fact was that Adams had been given a patch of sky 30 degrees by ten degrees to search for this possible planet.  He saw it right at the centre but unfortunately didn't recognise it.

      Now Martin took us back to Thales, credited as the first scientist, who, in 585 BC was able to predict a solar eclipse; his blunder was to fall into a ditch whilst looking up at the night sky but was recompensed by being retrieved by a pretty young girl.

      Thales was greatly respected by Aristotle who was born in 384 BC, but Aristotle's blunder was his belief that the Earth was the centre of a perfect Universe and the other planets and the Sun orbited around it.

      Aristarchus, born in 310 BC, came to the rescue by realising that in fact the Sun was the centre of our solar system and the Earth was in orbit around it.  By measuring the angle between the Moon and the Sun when the moon was exactly half lit and creating a right angle, he estimated that the Sun was about 22 times the distance from the Earth to the Moon, but his blunder was to believe that this distance was far to great and fiddled his measurements to make the Sun closer to the Earth.

      Eratosthenes, born in 276 BC, calculated that on the 21st June, the Sun shone directly down onto Alexandria.  Due south was a deep well at Aswan where the light from the Sun reached the deepest part only on June the 21st.  The distance between Aswan and Alexadria had been measured exactly by Pharaoh's Pacers (disciplined walkers with precise strides).  From these distances and angles Eratosthenes calculated that the circumference of the Earth was between 39,000 and 46,000 km.  (Now known to be 40,075 km)

      In 391 AD came a huge blunder when nearly all the books in the great Library at Alexandria were burnt, destroying most of the works by the ancient philosophers.

      Next, in about 1500 came Copernicus in Martin's list of astronomical blunders when the Catholic Church rejected his theories about the Earth and its orbit around the Sun and our position in the Cosmos.  Copernicus was followed by Galileo who confirmed the former's work but was again persecuted by the Roman Catholic Church and arrested only to be pardoned by Pope, Pope John as recently as 1999.

      Suspicion of science even caused Newton to feel he had to carry out some of his experiments in secret and behind curtains in the dead of night and also Darwin's publications were thoroughly questioned.

      Martin Frey concluded his talk by answering several questions from members; one asking about the suggested existence of a planet orbiting at the same rate as the Earth on the far side of the Sun locked in orbit at the third Lagrange point.  This turned out to be a blunder since space exploration has found this point not to harbour an unknown planet.

APRIL MEETING

    Wednesday 19th April 2006. Our own Ian King tells us about "Instrumentation".  Members remembering Ian's last talk about imaging will know of his use of instruments and the knowledge that goes with it.

FUTURE MEETINGS

    Wednesday 17th May 2006.  Dr. Robert Smith gives a talk with the alarming title of "Things that go Bang in the Night"

    Wednesday 21st June 2006.  We are to have a Members evening, and are calling it "Summer Solstice Telescope Evening" when members are invited to bring their telescopes along and any other astronomical equipment.  We also get the chance to discuss our interests and problems with others.  If any member would be interested in giving a short talk at this meeting they would be very welcome indeed and should contact Phil Berry, Ian Reeves or myself, Geoff Rathbone.  The subject does not have to be on pure astronomy, but experiences and visits to locations can be just as interesting.

    Wednesday 19th July 2006.  Gilbert Satterthwaite FRAS will be talking to us about "Sir George Airy's Contribution to Positional Astronomy".

    There will be no August meeting but Michael Harte is again kindly offering to hold a barbecue on Saturday 26th August 2006.  Last year we had an excellent evening with three or four telescopes and binoculars and great hosts, but it would be good to see more members this year.  Details to follow.

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OTHER NEWS

THE MONTHLY NEWSLETTER

    The monthly Newsletter is sent to all members of the Society with the intention of informing members of activities, meetings and some of the latest news on astronomical events.  All paid up members are entitled to receive it and we also send it out for three months after subscriptions become due, to non-payers.  If they wish to continue to receive it after that, please let Michael Wyles our treasurer know.

APRIL NIGHT SKY

    Now the spring has arrived it doesn't get dark until about 2100 BST.  Orion has virtually disappeared although Mars is still there but now has a magnitude of only 1.4.  Jupiter, magnitude -2.5, rises just before the Sun, as does Venus at -4. Saturn at -0.1 is still well placed to the south just after dusk.

      At present, Saturn is close to Leo whose head looks like a reversed question mark with Regulus as the dot underneath.

      Regulus has a magnitude of 1.36 and is a fairly hot star, 78 light years away.

      When looking at the night sky I tend to think of the stars as a static background.  Not a bit of it.  Quasars are so distant that they are used as almost static reference points against which the rest of the sky can be measured.  Barnard's Star is known to have the greatest proper motion with 10.7 seconds of arc per year.  Not very far from Regulus, at RA 11h 52' 42" Dec +37o 48' is "Groombridge 1830" moving at 7 arc seconds per year.  It is the third fastest moving star, and is 30 light years away with an apparent magnitude 6.4.  Its proper motion means that it will have moved the equivalent of the diameter of the Moon in just 250 years from now.  Regulus at 78 light years will take 7,000 years to travel that far, but in the opposite direction.

      Curiously, in 100,000 years the "W" in Cassiopeia will actually resemble a reversed question mark just as the head of Leo does now!  The star at the bottom of the question mark will be the star, which at present is the top right hand star of the "W". 

      During the same time "The Plough" will have become almost a straight line.  Of course, during this time, precession due to the Earth's wobble will be in its fourth period of rotation.

NASA SPACE PLACE  

Planets in Strange Places

By Trudy E. Bell

      Red star, blue star, big star, small star-planets may form around virtually any type or size of star throughout the universe, not just around mid-sized middle-aged yellow stars like the Sun. That's the surprising implication of two recent discoveries from the 0.85-meter-diameter Spitzer Space Telescope, which is exploring the universe from orbit at infrared (heat) wavelengths blocked by the Earth's atmosphere.

      At one extreme are two blazing, blue "hypergiant" stars 180,000 light-years away in the Large Magellanic Cloud, one of the two companion galaxies to our Milky Way. The stars, called R 66 and R 126, are respectively 30 and 70 times the mass of the Sun, "about as massive as stars can get," said Joel Kastner, professor of imaging science at the Rochester Institute of Technology in New York. R 126 is so luminous that if it were placed 10 parsecs (32.6 light-years) away-a distance at which the Sun would be one of the dimmest stars visible in the sky-the hypergiant would be as bright as the full moon, "definitely a daytime object," Kastner remarked.

      Such hot stars have fierce solar winds, so Kastner and his team are mystified why any dust in the neighborhood hasn't long since been blown away. But there it is: an unmistakable spectral signature that both hypergiants are surrounded by mammoth disks of what might be planet-forming dust and even sand.

      At the other extreme is a tiny brown dwarf star called Cha 110913-773444, relatively nearby (500 light-years) in the Milky Way. One of the smallest brown dwarfs known, it has less than 1 percent the mass of the Sun. It's not even massive enough to kindle thermonuclear reactions for fusing hydrogen into helium. Yet this miniature "failed star," as brown dwarfs are often called, is also surrounded by a flat disk of dust that may eventually clump into planets. (Note: This brown dwarf discovery was made by a group led by Kevin Luhman of Pennsylvania State University.)

      Although actual planets have not been detected (in part because of the stars' great distances), the spectra of the hypergiants show that their dust is composed of forsterite, olivine, aromatic hydrocarbons, and other geological substances found on Earth.

      These newfound disks represent "extremes of the environments in which planets might form," Kastner said. "Not what you'd expect if you think our solar system is the rule."

      Hypergiants and dwarfs?  The Milky Way could be crowded with worlds circling every kind of star imaginable-very strange, indeed.

      Keep up with the latest findings from the Spitzer at www.spitzer.caltech.edu/  For kids, the Infrared Photo Album at "The Space Place":

 spaceplace.nasa.gov/en/kids/sirtf1/sirtf_action.shtml introduces the electromagnetic spectrum and compares the appearance of common scenes in visible versus infrared light.

This article was provided by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

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CONTACTS

Chairman          Tim Bance                   01732 832745

                                   timbance@hotmail.com

Secretary         Ian Reeves                        01892 784255

Secretary        Phil Berry                        01892 783544

Treasurer         Mike Wyles                   01892 542863

                                    mikewyles@globalnet.co.uk

  Publicity         Michael Harte                       01892 783292

& Web site                    michael@greenman.demon.co.uk

  Editor            Geoff Rathbone                01959 524727

                  Geoff@rathbone007.fsnet.co.uk

Any material for inclusion in the May Newsletter should be with the Editor by April 28th  2006

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