WADHURST ASTRONOMICAL SOCIETY
APRIL NEWSLETTER 2007
INDEX: MEETINGS, OTHER NEWS, CONTACTS
The Big Questions in Cosmology
Given by Dr. Stephen Serjeant at the Society's meeting on Wednesday 21st March 2007
The evening's meeting was introduced by Phil Berry who explained that our speaker, Doctor Stephen Serjeant, is from the Open University and had travelled down from Milton Keynes especially for the Society's March meeting!
Stephen is the senior lecturer in Astrophysics in the Centre for Earth, Planetary, Space and Astronomical Research and he explained that his talk was based on answering the Big Questions in Cosmology as understood today, yet went on to say that research was redefining the answers more precisely all the time.
He posed the questions:
What is the fate of the Universe?
What is it made of?
How did it get as it is?
How old is it?
Will we get the answers in our lifetimes?
...and he went on to answer them pretty conclusively.
We were introduced to Omega o, the symbol for the amount of material there is in the Universe. If Omega o is less than, or equal to 1, then the Universe will expand for ever. If it is greater than 1, it will eventually collapse.
In 1963 Penzias and Wilson were trying to eliminate noise from a radio telescope horn in New Jersey. Even the effects of pigeon droppings in the horn were taken into account but eventually it was realised that all that was left must be background radiation from the Big Bang at the creation of the our Universe.
NASA used WMAP, the Wilkinson Microwave Anistropy Probe to measure variations in the temperature of the background radiation. It was discovered that these findings could be used to measure Omega o. The result found was that Omega o = 1.0 plus or minus 0.04! No conclusions there then...
In 1929, Edwin Hubble discovered evidence that the Universe was expanding by using the red shift of distant galaxies to show that these distant objects were receding the more distant they were from us. At the time, Einstein was struggling to make the case for a static universe in General Relativity and invoked the Cosmological Constant to hold it in place. Einstein later called this biggest blunder of his life.
Stephen showed a graph of the Cosmic Star Formation against red shift and then described how William Herschel had discovered infrared radiation when a thermometer, that had been left just outside the red end of the visible spectrum he was projecting through a prism, indicated an invisible source of heat.
We were then shown a photograph of the Orion Constellation in visible light, and then the same constellation in infrared. The remarkable image showed the whole of that part of the sky looking more like a huge swirling red cloud. Another image was of the Earth taken from space at 6 microns, which was completely unrecognisable apart from being spherical. In fact it looked like a ball of fiery eddy currents.
Using sub-mm light it has been possible to image the whole of the Universe at wavelengths not visible to the eye.
Primordial galaxies have been detected at great distances using SCUBA-2, a sub-millimetre Common User Bolometric Array which can "see" down to 14 Arc seconds. The results are too fuzzy to resolve the galaxies themselves, so the coordinates are being used to direct the SPITZER space telescope to the same area and so resolve these galaxies and confirm them optically. Stephen showed a number of results from SCUBA followed each time by the same area taken with the SPITZA telescope. The results were stunning, particularly in areas where a number of these galaxies had been found. These Primordial Galaxies were always very faint could not have been precisely identified without combining the results form SCUBA and SPITZER.
We looked at images of the Eagle Nebula, a birth place of stars and known as the "Pillars of Creation". Then Stephen showed the same area in sub-millimetre light and now the true centres of creation could be clearly seen.
Ultraviolet light from other sources in the area destroys some of the local dust, enabling nuclear reaction to begin and a star becomes active for the first time.
Due to the detection of Super Novae in these early galaxies, their magnitude can be determined and so their distances calculated but it has also been possible to estimate that for every 3 photons emitted, two are absorbed by dust before they get to us.
In 1998 astronomers were surprised to find that not only was the Universe expanding, but that it was also accelerating! It now looks as though Einstein had been correct all the time in stating the Cosmological Constant. Other evidence also confirms the Constant and combining this with the background radiation it is implied that we live in a flat universe that will expand forever and using this, it has now been determined that the Universe is currently calculated to be about 14 billion years old.
Dark matter is now known to exist, but what it is has still to be determined. Nutrenos have mass, but not enough. MACHOs (Massive Astrophysical Compact Halo Objects) are not enough, but WIMPs (Weakly Interacting Massive Particles) could be a prime candidate. Stephen feels that they will be detected experimentally in the next few years.
So to answer the Big Questions Stephen posed at the start of his talk, he intriguingly led us to the following conclusions:
The fate of the Universe
is to expand forever.
What it is made of is not known but should be known in a few years.
We understand more about how it got to be as it is all the time through looking at the birth of stars and galaxies.
It is 13.7 billion years old.
.And will we get the answers in our lifetimes? "Watch This Space!"
Stephen Serjeant presented a very complex subject in a very informative and entertaining way and I think everyone enjoyed his enthusiasm.
Questions from members led to suggestions of parallel universes possibly existing inside black holes and I don't think anyone left without further questions in our minds...
One thing Stephen left us with was a useful website for anyone interested in the Open University course on Observing the Universe. Course website: http://courses.open.ac.uk/sxr208 Registration: http://www.open.ac.uk and search for SXR208
A QUICK VIEW OF THE NIGHT SKY
Following the talk and coffee, despite the cold evening, a number of members met outside under a fairly clear night sky and spent a little while identifying planets, stars and constellations, using a new green laser as an effective pointing tool. My own laser was a little disappointing and proved later to have had a dodgy connection, but Phil Berry's laser was very impressive and a very useful pointing gadget.
POSSIBLE VISIT TO SEE CLOCKS AT GREENWICH AND FAVERSHAM
At the March meeting, Phil Berry announced that it may be possible to arrange a visit to the National Maritime Museum at Greenwich to see some of the Horological exhibits and also to visit Belmont House on the same day, Faversham where there is the finest collection of clocks in private hands.
Phil produced a table and asked those present to state whether they would be interested in taking part in a visit. The results from those present were:
Those interested in visiting
Those interested in only visiting Greenwich; 2
Those interested in only visiting Belmont House; 0
Members interested in weekdays and weekends; 10
Those only interested in weekdays; 17
Those only interested in weekends; 12
Wednesday 18th April 2007 Jerry Workman will return to update the Society with the progress of Mars Express. This follows on from Jerry's talk last October about the Mars Landers, particularly the spectacular exploits of Spirit and Opportunity.
The meeting commences at 1930 and will be held in the Upper Room of the Methodist Church, entrance to the left of the church and up the stairs, avoiding the Weight Watcher's meeting downstairs!The church is at the eastern end of Wadhurst High Street, opposite the gates to Upland College.
Wednesday 16th May 2007 Nik Szymanek will be talking about important basic facts in an introduction to CCD imaging. He calls his talk "Pixel Magic" and with his reputation for incredible images this promises to be an excellent talk.
Wednesday 20th June 2007 This will be an open Telescope Evening. A number of telescopes will be at the meeting for discussion and demonstration. Any members able to give a short talk will be very welcome and should contact Phil Berry who would be delighted to hear from them.
Wednesday 18th July 2007 George Satterthwaite will be giving a talk about "George Airy and His Contribution to Positional Astronomy".
August There is no meeting of the Society in August, but once again, we have been invited to an Astro Barbecue hosted by Michael Harte and his wife at Greenman Farm on Saturday 25th August 2007. Details to follow.
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Subscriptions for the coming year became due on the 1st of January 2007. Subscriptions remain the same as previous years at £15 per member and £20 for two members within the same family. Cheques should be made payable to "Wadhurst Astronomical Society" and can be presented to the Treasurer, Mike Wyles at the next meeting or can be sent to him by post if that is more convenient. Mike's address is: Mr. M. Wyles, 31 Rowan Tree Road, Tunbridge Wells, Kent. TN2 5PZ.
TELESCOPE FOR SALE
Chris Oliver is offering a telescope for sale. It is a 200 mm Sky Watcher f-1000 mm refracting telescope with an EQ5 mount with dual axis control.
The telescope has camera adapters and is on sale for £400 or near offer.Chris's telephone number is 01892 512306.
Phil Berry mentioned that after our meetings we could use a nearby location for observing. It has been too wet underfoot to use the site so far, but if the skies are clear, it would be possible to take binoculars, telescopes or just ourselves (and working green lasers...). Once we have used the site we will have a better idea of how we can best make use of it following the kind offer of the owner.
MARCH NIGHT SKY
Mercury is not suitably placed for observation this month
Venus is a prominent evening object at magnitude -4.0 and remains visible until about four hours after sunset.
Mars is poorly placed this month lying in the constellation of Aquarius (the Water-Bearer).
Jupiter (mag -2.4) in the constellation of Ophiuchus (the Serpent-Bearer) rises before midnight by the end of the month, but is fairly low in the sky even at culmination. A small telescope will allow the movement of the planet's four largest moons to be followed.
Saturn (mag 0.4) is excellently placed for observation for most of the night. It lies a little to the north and west of Regulus in Leo (the Lion).
For this months occultations I've included events for stars down to about mag 7. DD indicates that the star disappears at the dark limb of the moon. All times are in BST.
|Wed 18th Apr||21.26||298 Cet||7.1||DD|
|Fri 20th Apr||20.58||276 Tau||7.0||DD|
|Thurs 26th Apr||22.47||213 Leo||3.8||DD|
|Mon 30th Apr||21.25||143 Vir||6.9||DD|
ISSThere are many opportunities to see the International Space Station (ISS) this month. I've only chosen the passes when ISS is at its maximum brightness and elevation. All times are in BST. For more details log on to the web-site: - www.heavens-above.com
Observing the Sun
After the March meeting a number of members gathered in the College car park to see what naked eye objects we could find. One observation (!) that was made was that astronomy, by its very nature, tends to be carried out mostly in the dark and cold. In the main that is true unless you observe the Sun.
You can of course use one of the specially designed telescopes that blocks out all light apart from hydrogen alpha. This allows you to see the granulation on the surface as well as prominences and other phenomena. Most of us however will have to use our regular reflector or refractor.
The most popular method of observing the Sun and its spots is the projection method. With this the telescope is pointed towards the Sun and the image is allowed to fall onto a white card that is held up behind the eyepiece. Now might be a good time to repeat that familiar warning that you should NEVER look through any type of optical instrument at the Sun or you will blind yourself. The easiest way to roughly align the telescope is to look at the shadow it casts on the ground and get it as circular as possible. It will then only need a small amount of adjustment to get it spot on. DO NOT use the finder to look through - keep it capped. It is a good idea to set up another piece of card so that it casts a shadow onto the card with the image on, to make the image stand out. If other people are about always cap the scope, or move it, if you leave it for even a short while. This will prevent an accident for inquisitive eyes. The projection method is fine for a casual look but it is inconvenient if for instance you want to draw the sunspots or photograph them. You almost always have to hold the card and keep it still at the same time whilst trying to mark the position of the spots and maintain orientation.
Having said above never to look through a telescope at the Sun, this is exactly what the direct method does but with an important difference. This method requires you to fit a filter over the front of the telescope to block out most of the light. I use a Baader Astrosolar Safety Film to do this which I bought from David Hinds in Tring. The makers claim that it reduces the amount of light reaching the eyepiece by 99.999%. I made up a cardboard tube that was just the right size to fit snugly over the end of the scope. Over this I stretched the safety film and secured it in place. Being a snug fit is important as you don't want the filter to fall off easily. With the filter in place you can comfortably look at the Sun directly or take photographs of the sunspots which are easily visible. Don't be tempted to use the old style of filters that fitted into the eyepiece. These were always prone to shattering because all the heat is focussed there.
For those who can observe regularly, the Sun can be interesting to watch to see the gradual progression of its spots.
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Chairman John Vale-Taylor firstname.lastname@example.org
Phil Berry 01892 783544 email@example.com
Treasurer Mike Wyles 01892 542863 firstname.lastname@example.org
Publicity & Website Michael Harte 01892 783292 email@example.com
Newsletter 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 2007
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