Stargazey Pie March 2006
The End is nigh! Well, the end of winter anyway. Hopefully not the end of the world, although I suppose we can never tell. Certainly there was enough Human life in evidence at the March meeting, with a very healthy attendance, all keen to be entertained and informed. There was an excellent talk about extrasolar planets and their detection, news of some heavy-duty HAS promotion from Maarten, and a report of the latest observing sessions run by the Highlands Astronomical Society. In the captain’s chair was Pauline Macrae, with Maarten de Vries acting as ‘No 1’. Before the meeting could come to full warp power though, we trekked our way through the notices.
- Fame at last! The Highlands Astronomical Society is to be featured on a new DVD promoting the Highland Year of Culture 2007. More details below, under ‘Maarten de Vries and the Tartan DVD’.
- Let’s do lunch. All members should now have received invitations for a series of lunch time talks which are being given at Horizon Scotland, Forres, as part of Science Week. They are as follows:
Wednesday 15th Mar: ‘Watch where the wheeling systems darken’. Winter highlights and summer prospects captured by photographers of the local astronomical societies. Pauline Macrae will be showing a selection of members’ photos with highlights from this past winter, while Bill Leslie of Moray’s Astronomy Club, Sigma, will be showing images of the Sun taken with his solar telescope. This talk is winner of the Most Convoluted and Strange Talk Title of The Year, so do not miss it.
Thursday 16th Mar: ‘Bananas, Fish and Parlie Cakes’. Food scientist David Miskin of the new Food Innovation Institute at Horizon Scotland will talk on the opportunities and challenges of developing food for the future.
All the talks will start at 12.30pm sharp, with refreshments at 1.15pm. They are completely free, but it is advisable to book ahead by emailing David Williams here, or calling 01309 696010.
- Observing Sessions. Observing sessions for March and April 2006 are as listed below, and the 1st April one is not a joke (unless the weather has the last laugh)! These events are weather-dependant- if it is good we will be there, but if there is any doubt please phone the contact number for the night before 7.30pm or the mobile number after 8pm.
Friday 24th Mar............Pauline Macrae
Saturday 25th Mar.........Trina Shaddick
Friday 31st Mar..........Maarten de Vries
Saturday 1st Apr.............Alan Mumford
Pauline also gave a brief report on recent observation sessions that have taken place at the Culloden observatory. On Friday 24th February a number of members and non-members gathered there with a variety of telescopes to observe Mercury low in the southwest after Sunset. At the time Mercury was at its greatest separation from the Sun, so was at its best for observing. It was a bit of a struggle to find, but eventually it was pinpointed and several telescopes were trained on it, including our star-performer 12” ‘HASDobs’ Dobsonian-mounted Newtonian.
On other occasions we have enjoyed fantastic views of deep sky objects and the planets, particularly Saturn in recent nights. Many people who come up to the observatory are getting their ‘first views’ of objects, and some are getting their ‘best views’ thanks to the equipment and the experience that the observing team possess, so if you want to see this winter’s observing season out with a great observing experience try to come along to one of the sessions listed above. Weather permitting…
Although these are the last regular sessions for the season, there will be further Lunar, Planetary and Double-Star sessions through the spring and summer. Keep an eye out on the website, particularly the events page for details.
- The Green House Effect. The cost of hiring our current venue, the splendidly equipped Green House, has increased by £10 to £60 per month, plus security man, plus VAT! Your Committee still feels that the cost is justified considering the excellent facilities. Treasurer Pat Escott stated that the Society’s income is good enough, so Chairwoman Pauline Macrae has signed the agreement and committed us to the venue until April 2007. It is hoped that the new Visitor Centre which we hope to use for our future meetings may be up and running by then and so we will review the situation at that time.
- AGM. Next month is AGM month, so the April meeting will be the…guess what…AGM! It is required by the constitution that this be told to us for 10 months preceding the event itself, so you may all now consider yourselves told!
- Step in and Speak Up. Our speaker for the May 2nd meeting, Dr Alyson Calder, has had to cancel due to other constraints on her time. The Chairwoman therefore has intentions of letting some of our members present some short talks or presentations on any topic with an astronomical slant. You may be approached, or you could of course volunteer. Interested? Then please contact Pauline to discuss the details.
- The Sun and the Moon. There is a penumbral lunar eclipse on the night of 14th/15th March. This is when the Moon passes through the northern part of the Earth’s shadow- known as the Penumbra. The Moon will not change very much in brightness, but its southern hemisphere should become noticeably darker at mid-eclipse at approximately 23:47 GMT. The whole event lasts from 21:22 until 02:13 GMT, but as there is nothing dramatic to see no special viewing event has been planned by the Society. Two weeks later, on 29th March, there will be a partial solar eclipse from 10:59 BST until 11:36 BST. From Inverness, the Sun will only be 8.8% eclipsed, so it is not really worth the Society organising a viewing event for this either. However, if you decide to view it from home- Do NOT look at the Sun with your naked eye. Projecting the image of the Sun is the safest way to view it, or you can use eclipse glasses. Telescopes or binoculars should only be used directly if they are fitted with safe and fully tested solar filters.
- Is it getting warmer in here? Several of the Society’s Ladies-in-Learning are studying an Open University course on weather and climate. As part of this they are running computer desktop climate model simulations as part of a huge experiment to see if we can predict what sort of climate changes we will undergo in the 21st century. If you’d like to join in this experiment (and have your very own little world on your computer desktop- Ah, the power!) just visit this link to find out all about it.
- Mars Recon. By the time you read this, Mars Reconnaissance Orbiter will be in orbit around its destination- the Red Planet. Launched on 12th August 2005, the vehicle has spent nearly 7 months journeying to Mars, and once there, will start braking and inserting itself into orbit. This process will take another six months, but then the mission objective of looking for evidence of water on Mars will begin. Visit the Mars Reconnaissance website to learn more about this important mission.
- Geology Talk. There will be a talk by the Geology Club, on meteorites, asteroids and comets, which will take place on Tuesday 14th March at the Spectrum Centre in Inverness. The talk will start at 7.15pm, and entrance will cost £3.00.
Maarten de Vries and the Tartan DVD.
After the notices, Maarten told us about the day he and Howie Firth recently spent at Eilean Donan Castle, taking part in the making of a DVD which will showcase Scottish scientific and cultural groups. In reply to his invitation, Maarten asked what the advantage would be for the Society if he took part. He was told that he would be interviewed, and could take along a prop. The prop he took was the 12” HASDobs telescope, which is a star of our observing sessions and has become a trademark of the Society.
The interview went well, and it seems Maarten promoted the Highlands Astronomical Society quite heavily. He will be receiving copies of the DVD once it is finished, and it is hoped that we’ll be able to see it at a future meeting.
The DVD will officially be launched at the Tartan Day celebrations in New York, 6th April, so we will soon become even more internationally well-known! Quite apart from his promotional duties, Maarten and Howie enjoyed a tour of the Castle, and became ‘extras’ in the filming of the other interviews and scenic footage that was filmed. The Castle guides were both interested in astronomy, and contact details have been exchanged- will this lead to linked future events? Watch this space…
Eyes on the Skies.
Make the most of the dark skies that we still have, for the clocks ‘spring forward’ on Sunday 26th March, and we will instantly lose an hour of darkness in the evening. Yes, it is depressing, but don’t worry too much, as we still have some great constellations to explore and many objects to see if you are willing to go outside an hour later to make up for the darkness shortfall.
Leo is up and about, with handfuls of galaxies to be sought out with telescopes of all apertures. See here for more details about Leo in the March Seeing Stars article. If this wets your appetite for more animal themed constellations, you might want to seek out Canis Major, the Great Dog at Orion’s heel. Canis Major is the constellation in which Sirius, the brightest star in the sky, resides. It can be seen to twinkle and shift colours as you look at it, as it lies very low over the horizon and suffers atmospheric distortion that makes it rather appealing to the naked eye, but somewhat overbearing in a telescope! It is quite impressive to watch it shift from white to red to green and back in the space of a second or two. If it lay higher in our sky it would certainly be more visually stable, but I suspect it would lose some of its charm.
M41 is an interesting open cluster that lies 4 degrees south of Sirius, and contains about 100 stars of 7th magnitude or so. It is not very visually impressive, but it is so often ignored in favour of more impressive or more easily observed clusters like M45 or M35. Have you seen M41? Chances are you haven’t looked at it very often, so I for one intend to give it another view this month. Go on, observe a neglected cluster tonight!
Saturn is almost overhead now, and well away from any atmospheric distortion near the horizon. This could be the time to get out the short focal length eyepieces and zoom in for some high power views of the rings. Saturn will be a target of choice at the Culloden observing sessions this month, so remember to drop by if you get a chance, and sample the view in the Society’s 10” reflector, and possibly the 12” HASDobs, which in a recent session actually showed the Encke Gap in the A ring with ‘relative’ ease at 384x magnification! Of course such views depend to a large extent on the quality of the ‘seeing’, so hope not only for dark skies, but steady ones also if you wish to make out that sort of detail in the eyepiece.
So it is the beginning of the end of this observing season, at least as far as deep sky objects are concerned, but there is still a while left to explore and enjoy the sky, so let’s hope we can make the most of it as spring Marches on…
The Main Event.
‘Life and Death in other Planetary Systems- Are we alone?’ by Jane Greaves
Jane Greaves has a PhD in astronomy, and has worked in Edinburgh, Hawaii and St Andrews. In Hawaii she was responsible for helping British astronomers use the James Clerk Maxwell telescope, named after the famous Scottish physicist. She now teaches astronomy, and hopes that her new field of ‘astrobiology’ –which explores the possibilities of life outside the solar system- becomes an area of research that Scotland takes the lead in.
Given Jane’s experience and current position, she is the ideal person to illustrate the processes of planet formation, and the ways in which they affect the possibility of other planetary systems, and life, forming.
Planets form from stuff left over from the process of star-formation. The extra gas and dust goes towards making the rocky planets and gas giants that orbit many stars. This takes place usually within the first 100 million years of a star’s life, which in terms of a human lifespan would be within the first year of life.
Jane showed an image of the Spitzer Telescope, which observes in the infrared wavelengths. This allows it to peer through the obscuring dust clouds of space to detect the heat radiating from areas beyond. It can detect discs of material surrounding stars, which may be places of planet-formation. We saw an image of one such area, where tiny pinpoints of light showed at the end of columns of gas and dust, indicating regions where stars had just formed or were still forming- stellar nurseries which might in the future hold systems of planets orbiting these young stars.
The first extrasolar planet to be found was discovered in 1992 by Aleksander Wolszczan and Dale Frail, who monitored a pulsar and noticed that the frequency of the ‘pulse’ was sometimes irregular. They concluded that this was caused by the gravitational influence of a planet in orbit around the pulsar (PSR 1257+12). In 1995 Michel Mayor and Didier Queloz detected a Doppler shift coming from the light of the main sequence star 51 Pegasi, and found that this was caused by a wobble in the planet’s motion, brought about by the presence of a planet orbiting the star. Many more discoveries followed, including extrasolar planets in orbits around the stars 55 Cancri, 70 Virginis, 16 Cygni B, Mu Arae and dozens more. To date, more than 150 have been discovered.
Most of the extrasolar planets found are gas giants, and the majority of them have very short orbital periods- sometimes only a few Earth-days long. In 1997, British scientists started thinking about the possibility of detecting ice giant type planets, similar to Neptune, so began using the SCUBA camera on the James Clerk Maxwell telescope in Hawaii. This camera operates at wavelengths of about 1mm or less, allowing it to penetrate the shrouds of dust and gas which separate us from the stars being studied. The new SCUBA 2 camera will continue the work but with more advanced technology.
One of the stars studied, Epsilon Eridani, showed an image that was very similar to a simulated view of our Sun from a distant world. Material around the star has been ordered into rings, which suggests that there are planetary bodies ‘shepherding’ the material. There may well be an ice giant in orbit around Epsilon Eridani, but the chances of finding an Earth-type planet here are tiny, as the ‘habitable zone’ (where an Earth-type planet may exist) around the star is very small. Also, any gas giants in the system would wreak havoc if their orbits took them close to, or through, the habitable zone.
But then, it could also be argued that such disruption could lead to rapid environmental changes, and that these could stimulate life and evolution rather than precluding it. If life were to develop on a world that was under heavy bombardment by comets, meteorites and other bodies, it might develop under oceans of water introduced to the planet by cometary impacts.
The Pleiades is a young star cluster typical of the type that may have planetary systems forming around its member stars right now, and is currently under scrutiny. Already one star in the cluster has been found to have a dust ring, and this, combined with the fact that the stars in the cluster are about 100 million years old, bodes well for finding an extrasolar planet there.
But not all extrasolar planets that have been discovered are ‘giant’ types. One rocky planet has been found, using a new technique known as gravitational microlensing. This technique detects variations in brightness around a star whose gravity causes it to act as a lens when viewing the light of a more distant star. The variation can be caused by a planet orbiting the ‘lens’ star. See here for more details on this fascinating process. The planet in question is thought to be rocky and about 5 times the mass of Earth. It is a long way off though- 20,000 light years in the direction of the centre of our galaxy. Perhaps one day a closer one may be found, and certainly the future looks bright in this field of astronomy, with talk of building a massive 100m telescope to detect very faint, small, Earth-type planets.
We would like to thank Jane very much for her presentation, which was full of detail and had some great images of the equipment being used and the processes involved in the search for new planets and life beyond the solar system. She finished her excellent talk with a very positive thought- she considers it realistic to expect to have found an Earth-type extrasolar planet within the next 15-20 years! We live in very interesting times.
Did I mention that next meeting is the AGM? Well I meant to, as it’s the AGM and if you want to attend the AGM (which is usually a very exciting and informative meeting to attend) then you’ll need to turn up at the Green House on Tuesday 7th April in good time for 7.30pm. That’s when the AGM starts. You will be receiving a copy of the Chairperson’s yearly report by email or snail-mail before then, so if there are any issues you would like to raise you will be able to do so at the meeting. There will also be a DVD shown, but title is still to be confirmed.