Monday, 16 June 2014

Midsummer BBQ, Solarfest, Solstice, NLCs, Birth of Moon, Talks, Videos, GB Visit

Hi all,
1. IAA Midsummer BBQ, 28 June, at Armagh Observatory:
The IAA's midsummer BBQ will be at Armagh Observatory, on the afternoon of Sat 28 June. We also hope to include a visit and show at Armagh Planetarium - details to be confirmed. The day will also include a tour of the Observatory and some of the main telescope domes, and a visit to another very interesting but lesser known astronomical item in Armagh! Full details here within the next few days.
2.   SOLARFEST, DUNSINK Observatory, Dublin: Solarfest 2014 is now confirmed for Saturday 21st June. Free event, but places must be booked in advance
3. Summer Solstice: 21 June, 11.51 BST. The Sun will reach its most Northerly point along the ecliptic at 10.51 UT, or 11.51 BST. That is almost as long a day as it is possible to have here. A little teaser: what circumstances would have to apply for the Summer Solstice 'longest day' to reach its theoretical maximum duration at your own location (in Ireland)? Answers by email for an honourable mention in the next bulletin.
4. Noctilucent Clouds (NLCs). We are now in the season of visibility for these ethereal high altitude clouds, visible when the sky is nearly totally dark, as they lie well above the height of ordinary clouds. They are thought to be connected with high altitude fine debris from meteors which have burned up high in our atmosphere. Look low in the Northern sky near local midnight
5. Watch the construction of the ISS - an amazing video:  
6. Free Lecture at Ulster Museum: Thurs 24th July, 19.30, at the museum: "Heavy elements from giant red stars" - Free, but places must be booked in advance. This lecture, by Dr. Amanda Karakas from Mt Stromlo Observatory, Canberra, ties in with the excellent exhibition on "The Elements" currently running at the Museum. Details on:
7: IAA Solar Day, WWT, Castle Espie. We will be holding another one of these very popular events on Sunday afternoon, 17 August. More details later.
8. Birth of Moon - latest theories:
   Theia is supposed to have been 'Mars-sized'. Mars is approximately 1/10 the mass of the Earth.  
The big question remaining is: Where is Theia now, or what happened to it? The conventional theory is that most of it became absorbed into the Earth. But that's unlikely if, as generally postulated, it was a glancing impact. And if it was a more direct impact, it would have shattered the impactor (and maybe the Earth too), so that the ejecta would have comprised both core and mantle material, and therefore the Moon would be much denser than it is.
   As a total non-expert, I'm tempted by the idea that the remains of Theia went on, probably via an indirect route, close to the Sun and eventually became what we now know as Mercury!
       Yes, I'm probably going to be shot down by the planetary dynamicists, but it would explain some unusual features about Mercury
1. It has the largest orbital eccentricity of any of the planets: 0.20563, compared with only 0.00678 for its neighbour Venus.
2. It has the highest orbital inclination of any of the planets: 7.005 degrees, compared with 3.395 for Venus, the second highest.
3. It has the second highest density of any of the planets, just beaten by Earth: 5.43 compared with 5.52. But if we allow for the higher compaction of Earth's core due to its greater mass, in fact Mercury's density would be the highest of all.
    All that ties in with a picture that its lower density outer crust was stripped off by the collision, (which then mostly formed our Moon), especially if Theia and Earth were contra-rotating at the point of collision, leaving the high density metallic core to proceed along an orbit towards the Sun, a bit out of the ecliptic plane, where it was captured by the Sun but retaining a high degree of ellipticity. And Mercury is about half of the mass of Mars, which would be about right for what would be left of the inner dense core of Theia which eventually ended up as Mercury. 
   Otherwise it's quite hard to explain Mercury's high density, and both its high orbital eccentricity & inclination, which would be unusual in the inner part of the planet-forming disc around the Sun.
   OK, I know that I'm getting into Velikovsky territory, so I'll stop there!
    I suppose we'll just have to wait for a Mercury lander to sample the isotope ratios....
9. European Week of Astronomy and Space Science (EWASS), Geneva, Switzerland, 30 June – 4 July. The annual European Week of Astronomy and Space Science (EWASS) conference will take place in Geneva from 30 June to 4 July. Bringing together astronomers and space scientists from across Europe, EWASS sessions cover topics from star formation in galaxies to the origin of cosmic dust and astronomy using the SKA and ALMA observatories. See Contact: Conference Secretariat,
10. INTERNATIONAL METEOR CONFERENCE, 2014  Thursday September 18 till Sunday 21 September 2014, Giron, France. Giron is a small village located in the south of the Jura Mountains close to Geneva. The region is easily reachable by air (Geneva or Lyon airport), by train (TGV high speed train from Paris and InterCity trains from Geneva railway station) and by car (highway A40 Lyon-Chamonix). Part of the attraction for this event is that a free visit to CERN is included in the price! See
Galway Astrofest: Feb 21, 2015
COSMOS: April 17th to 19th 2015, Shamrock Lodge Hotel, Athlone.
12. Garden Party at BP + Greenwich  & Herstmonceux
 At long last I managed to get a suitable date for the Garden Party at Buckingham Palace in honour of my recent BEM award. Angela and I decided to make it a week's trip, taking in some astronomy along the way. We had a great time, and had a very fortuitous meeting with Prof Don Kurtz of University of Central Lancashire who gave us an excellent lecture in Belfast about a decade ago. He was the only other one at BP that I knew. We had a good chat, and he has agreed to give us another lecture in the coming season. More on that when the dates are agreed.
   We also had a day at the old Royal Observatory, Greenwich, and another day at the Royal Greenwich Observatory. Confused? The former is the original, dating back to King Charles II, in E. London. The latter is the site where the RGO moved to for a period, at Herstmonceux Castle in Sussex, in the Fifties. It later moved from there to Cambridge, but six major telescopes in their domes remain, and form the basis for an excellent Science Centre. The original giant dome for the 100-inch Isaac Newton Telescope (which is now in La Palma) is also at that site, but not open to the public. The IAA hopes to run a trip to some astronomy sites in GB, probably including those two, in the next year. Watch this space.
13. INTERESTING WEBLINKS: Interesting piece, even though the top illustration is totally wrong: asteroids do not trail tails of fire before they hit the Earth's atmosphere! There's something not right in the text of this article: I assume that the reference to the new planet 'having a mass between that of Mars and Saturn' should say '.... a mass between that of Uranus and Saturn'. A very dangerous idea: after all, they might evolve into something like us! (qv: Syria, Iraq, Ukraine, Sudan, N. Korea, Ulster, Tuam, treatment of women in many countries, etc etc) It's a new 'Space Race', I guess. It's official! NASA has a flying saucer.... and If it's that old, it's unlikely to have the right mix of elements to support advanced life.
and NB: the note that "this star is the second fastest moving star in the sky" needs to be qualified - that speed is just its apparent motion across the sky relative to the background because it's very close, not its absolute motion through space. Just like a low-flying bird can appear to cross the sky in a few seconds, whereas a much faster high altitude jet takes many minutes.
NASA's plans for human space exploration:
Mercury Transit - from Mars: The next one visible from Earth will be on 9 May 2016, and it will be the longest of 21st Century.
14. TWITTER: Follow the IAA on Twitter: The account is now operational again as before: @IaaAstro.

15. JOINING the IRISH ASTRONOMICAL ASSOCIATION is easy: This link downloads a Word document to join the IAA.
    If you are a UK taxpayer, please tick the 'gift-aid' box, as that enables us to reclaim the standard rate of tax on your subscription, at no cost to youYou can also make a donation via Paypal if you wish: just click on the 'Donate' button.  See also
Finally, in tribute to the late great John Dobson, a quote from him which is typical of the man, and very appropriate:  "If you figure something out for yourself, it doesn't make no never-mind who figured it out first, it's yours."
Clear skies,
Terry Moseley