Date: 16 June 2010 00:23:04 GMT+01:00
Subject: IAA/UAS Event update; Comet update, NO Dark Energy?
1. IRISH ASTRONOMICAL ASSOCIATION / ULSTER ARCHAEOLOGICAL SOCIETY / NIEA SOLSTICE EVENT, SATURDAY 19 JUNE - UPDATE
Thanks to Maria Hanna for pointing out an error in one set of directions. If going from Downpatrick via the B176, see below for the correct directions
The IAA + UAS, in conjunction with the Northern Ireland Environment Agency, will be holding another joint event to mark the summer solstice, with a visit to Ballynoe Stone Circle, near Downpatrick, Co Down. This is the largest and most impressive and complex stone circle in Northern Ireland, and one of the biggest in Ireland, and may well have a winter solstice sunset alignment.
See, for example: http://www.megalithomania.com/show/site/270/ballynoe_stone_circle.htm and http://www.megalithicireland.com/ and http://www.themodernantiquarian.com/site/1048/ballynoe.html
We will visit the stone circle (SC) at 14.00, where there will be talks about the archaeology and possible astronomical connections, and then adjourn to the nearby beach at Minerstown for a BBQ/picnic. In the case of bad weather, there are two local pubs for refreshments.
DIRECTIONS: Ballynoe Stone Circle is on Ballynoe Road, which runs SSW from Downpatrick towards Dundrum Bay. It's about 2.5 miles from Downpatrick, at Map Ref:J481404
From Downpatrick, there are two possible routes:
1. From the town centre, take the B 176 (Irish St) towards Killough, and turn right at into Ballynoe Road just on the S outskirts of the town. You go past Downe Hospital, and past the junction with the B1 on your left. Proceed round a noticeable left hand bend, then go straight ahead at a mini roundabout, then take the second right (it'll be signposted for 'Tyrella' with the Stone Circle tourist sign underneath). This is the Ballynoe Road, which leads straight to a crossroads with The Castle Inn pub on your right after about 1.5 miles. Proceed on through the cross roads and in about 200 yds you'll see the small 'Tourist' sign for Ballynoe Stone Circle. Maria adds "And the last time I was there, the sign at the actual SC was green, not brown which made it a bit more difficult to spot in the midst of the hedges!"
2. Take the main A25 from Downpatrick towards Clough and Newcastle etc. Turn left at the first crossroads after Downpatrick Racecourse (which is on your left) - it's about 1 mile past the Racecourse. This will take you into Bonecastle Road. Go across the first crossroads, then turn left at an angled T-Junction. In about 400 yards you will come to the crossroads with the Castle Inn pub on your left. Turn right at this cross roads onto Ballynoe Road, and in about 200 yds you'll see the small green 'Tourist' sign for Ballynoe SC.
IF APPROACHING FROM CLOUGH (on the main Belfast - Newcastle Road) take the A 25 from Clough towards Downpatrick and turn right at the crossroads about 4 miles from Clough (it's the first proper crossroads you come to on that road) into Bonecastle Road, then proceed as for '2' above.
PARKING: There is limited parking at the roadside at the entrance to the SC, but if there isn't enough room there, more parking is available a bit further out along Ballynoe Road at a small group of houses, within easy walking distance.
ACCESS: The SC is about 1/3 mile (1/2 km) off the road along an unpaved path, and requires negotiation of an 'up and round' stile, so this visit would not be suitable for anyone with anything more than slight mobility problems. Also the site is quite exposed, with no shelter, so bring clothing and footwear appropriate for the weather. But if the weather is good, it's a fabulous spot!
BALLYNOE S/C: The Circle is unique among Irish SCs (as far as I know), because of the large internal, oval, off-centre raised cairn surrounded by its own small kerb stones, and also because of the complex of what I call 'entrance stones', which are quite large, and form a sort of portal. But the archaeologists can give a better explanation than I can. There are also more large outlying stones than I have seen at any stone circle in Ireland, which is another distinguishing feature.
Some websites also refer to a large stone with prominent 'cup-marks', but I will provide an alternative explanation!
ASTRONOMICAL CONNECTION? The astronomical connection seems to be that at midwinter solstice, the sun sets (or used to 3,000 - 4,000 years ago) from the SC in the very prominent notch formed by the gap between Slieve Donard and Slieve Commedagh, the two highest mountains in the Mourne Mountains across Dundrum Bay (as for Drombeg Circle in Co Cork: see http://www.megalithics.com/ireland/drombeg/drbgmain.htm). This provides a very accurate way to measure the exact date of the solstice. There may be other alignments too - all waiting to be discovered!
PICNIC/BBQ AFTERWARDS: Afterwards, unless it's raining, we will proceed to the seashore at Dundrum Bay for a picnic/BBQ: there are two parking lay-bys at the roadside just beside Minerstown Beach, about 1m East of Minerstown Caravan Site, at MR: J505361. There are no picnic tables, so bring a folding table and chair, or at least a waterproof-backed rug to sit on the ground. I will provide maps on the day to enable you to find your way there, but basically you just go to the main A2 Coast Road, 1m East of the Caravan Park. (You can bring a snack to the Stone Circle with you, but because of the distance, you wouldn't want to carry very much! Also, we don't want ANY litter at the site, and we certainly do not want any barbecues there!)
CONSUMABLES: Bring your own! Bring your own food, drink, plates, cutlery, cups, glasses etc, and if you want to BBQ, bring your own portable or disposable one. And matches or a lighter, and BBQ tongs etc.
(BTW, do NOT believe the fanciful and totally erroneous explanation given for the origin of the word 'barbecue' on the Alan Simpson Show on Radio Ulster last week! He claimed that it came from the French words for 'beard' and 'tail', but it's actually from a Spanish word, 'barbacoa', originally from Haitian, meaning a framework of posts and sticks on which animals were roasted. This is confirmed by both the Shorter and Concise Oxford Dictionaries, and Chambers Twentieth Century Dictionary, all highly authoritative sources.)
PLAN B: If it's wet, there are two pubs fairly nearby: The Castle Inn, on Ballynoe Road, at Ballynoe Cross Roads, just 200 yds from the entrance to the SC, and the Ramble Inn, at Corbally, about 2m to the West.
Please let me know if you intend to go, so we can get some idea of likely numbers (there's no charge, BTW)
2. Comet McNaught 2009 R1: I got a really good observation last night, with a totally clear, but bright twilight sky. 15 June, 00.10 UT (01.10 BST): Comet 0m.2 brighter than HIP 17437, and 0m.2 fainter than HIP 18212, giving an average of magnitude 5.9. This is almost exactly in line with the predicted magnitude.
3. NO NEED FOR 'DARK ENERGY'? I've always had my doubts about 'Dark Energy', which I'm sure many of you have heard me express on various occasions! It seems too much of an ad-hoc hypothesis, almost reminding me of the Ptolemaic System's ever increasing complex system of cycles, epicycles and deferents.
Now, new research by astronomers in the Physics Department at Durham University has thrown doubt on the present version of the 'Standard Model' of the universe, in which about 75% of the total is comprised of so-called dark energy, which is supposed to be making the expansion rate of the universe speed up, instead of slow down.
Additional research covered samples from the SDSS surveys, comprising 1.5 million galaxies, with a redshift range between 0.2 and 0.9, over 7600 square degrees of the sky, and comprising a volume of space of 5.5h>-3 Gpc>3.
Their findings show very little positive evidence for the "Integrated Sachs-Wolfe" (ISW) effect, which is one of the main bulwarks of the Dark Matter/Dark Energy theories. The standard Cold Dark Matter model is rejected at 2-3% significance. (The ISW effect is caused by gravitational redshift of photons, and occurs when the universe is dominated in its density by something other than matter.)
The following is adapted from an RAS Press Release:
New research by astronomers at Durham University suggests that the conventional wisdom about the content of the Universe may be wrong. Graduate student Utane Sawangwit and Professor Tom Shanks looked at observations from the Wilkinson Microwave Anisotropy Probe (WMAP) satellite to study the remnant heat from the Big Bang. They find evidence that the errors in its data may be much larger than previously thought, which in turn makes the standard model of the Universe open to question. The team publish their results in a letter to the journal Monthly Notices of the Royal Astronomical Society.
Launched in 2001, WMAP measures differences in the Cosmic Microwave Background (CMB) radiation, the residual heat of the Big Bang that fills the Universe and appears over the whole of the sky. The angular size of the ripples in the CMB is thought to be connected to the composition of the Universe. The observations of WMAP showed that the ripples were about twice the size of the full Moon, or around a degree across.
With these results, scientists concluded that the cosmos is made up of 4% ‘normal’ matter, 22% ‘dark’ or invisible matter and 74% ‘dark energy’. Debate about the exact nature of the ‘dark side’ of the Universe – the dark matter and dark energy – continues to this day.
Sawangwit and Shanks used astronomical objects that appear as unresolved points in radio telescopes to test the way the WMAP telescope smoothes out its maps. They find that the smoothing is much larger than previously believed, suggesting that its measurement of the size of the CMBR ripples is not as accurate as was thought. If true this could mean that the ripples are significantly smaller, which could imply that dark matter and dark energy are not present after all.
Prof. Shanks comments “CMB observations are a powerful tool for cosmology and it is vital to check for systematic effects. If our results prove correct then it will become less likely that dark energy and exotic dark matter particles dominate the Universe. So the evidence that the Universe has a ‘Dark Side’ will weaken!”
In addition, Durham astronomers recently collaborated in an international team whose research suggested that the structure of the CMB may not provide the robust independent check on the presence of dark energy that it was thought to.
If dark energy does exist, then it ultimately causes the expansion of the Universe to accelerate. On their journey from the CMB to the telescopes like WMAP, photons (the basic particles of electromagnetic radiation including light and radio waves) travel through giant superclusters of galaxies. Normally a CMB photon is first blueshifted (its peak shifts towards the blue end of the spectrum) when it enters the supercluster and then redshifted as it leaves, so that the two effects cancel. However, if the supercluster galaxies are accelerating away from each other because of dark energy, the cancellation is not exact, so photons stay slightly blueshifted after their passage. Slightly higher temperatures should appear in the CMB where the photons have passed through superclusters.
However, the new results, based on the Sloan Digital Sky Survey which surveyed 1 million luminous red galaxies, suggest that no such effect is seen, again threatening the standard model of the Universe.
Sawangwit says, “If our result is repeated in new surveys of galaxies in the Southern Hemisphere then this could mean real problems for the existence of dark energy.”
If the Universe really has no ‘dark side’, it will come as a relief to some theoretical physicists. Having a model dependent on as yet undetected exotic particles that make up dark matter and the completely mysterious dark energy leaves many scientists feeling uncomfortable. It also throws up problems for the birth of stars in galaxies, with as much ‘feedback’ energy needed to prevent their creation as gravity provides to help them form."
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