Date: 16 February 2011 19:40:10 GMT
Subject: Aurora? IAA Talk, NanoSail-D, New Giant planet? GAF, Astro - St Pat, Cosmos, BCO
1. POSSIBLE AURORA TONIGHT?
MAJOR FLARE: Earth-orbiting satellites have detected the strongest solar flare in more than four years. At 0156 UT on Feb. 15th, giant sunspot 1158 unleashed an X2-class eruption. X-flares are the strongest type of x-ray flare, and this is the first such eruption of new Solar Cycle 24. The explosion that produced the flare also sent a solar tsunami rippling through the sun's atmosphere and, more importantly, hurled a coronal mass ejection toward Earth. This raises the possibility of geomagnetic storms in the days ahead.
The local BBC radio news has already given an alert for a possible aurora tonight, which may be a bit optimistic, especially in view of the bright gibbous moon. Nevertheless, if you have a clear sky, do have a look, and let me know by text to 07979 300842 if you see anything.
Visit http://spaceweather.com for images and updates on the X-Flare.
2. IAA LECTURE MEETING: "Extreme Objects in our Solar System". 9 February, 7.30 p.m., Bell Lecture Theatre, Physics Department, QUB. The next lecture in the Irish Astronomical Association Lecture Programme, will be by Dr Pedro Lacerda, of QUB: (Note, this lecture is a change from that on the Programme Card - it is a swap with the following one.)
Last year Pedro gave one of the best received lectures we have ever had, so we just had to invite him back! He makes a fascinating subject totally accessible to even the newest of beginners, while still managing to get across all the relevant detail.
This lecture will cover some of the oddest and most interesting objects in our own solar system, and will be of extra interest in view of the latest news item about 'Tyche' - see Item 4 below.
Admission is free, including light refreshments, and all are welcome. There is free parking on the QUB site after 5.30 p.m.
For details of all forthcoming IAA lectures and other events, see www.irishastro.org
3. NANOSAIL-D: NASA's first Earth-orbiting solar sail, NanoSail-D, is circling our planet and attracting the attention of sky watchers. Occasionally, sunlight glinting from the sail's reflective fabric produces a flash of light in the night sky. These "solar sail flares" are expected to grow brighter as NanoSail-D descends in the weeks ahead. The current passes over Ireland are not very favourable, but will improve towards the second half of the month. Details of passes for your own location are on www.heavens-above.com.
NANOSAIL-D AMATEUR ASTRONOMY IMAGE CONTEST
NASA has formed a partnership with Spaceweather.com to engage the amateur astronomy community to submit the best images of the orbiting NanoSail-D solar sail. NanoSail-D unfurled the first ever 100-square-foot solar sail in low-Earth orbit on Jan. 20.
To encourage observations of NanoSail-D, Spaceweather.com is offering prizes for the best images of this historic, pioneering spacecraft in the amounts of $500 (grand prize), $300 (first prize) and $100 (second prize).
The contest is open to all types of images, including, but not limited to, telescopic captures of the sail to simple widefield camera shots of solar sail flares. If NanoSail-D is in the field of view, the image is eligible for judging.
The solar sail is about the size of a large tent. It will be observable for approximately 70 to 120 days before it enters the atmosphere and disintegrates. The contest continues until NanoSail-D re-enters Earth's atmosphere.
NanoSail-D will be a target of interest to both novice and veteran sky watchers. Experienced astrophotographers will want to take the first-ever telescopic pictures of a solar sail unfurled in space. Backyard stargazers, meanwhile, will marvel at the solar sail flares
-- brief but intense flashes of light caused by sunlight glinting harmlessly from the surface of the sail.
NanoSail-D could be five to 10 times as bright as the planet Venus, especially later in the mission when the sail descends to lower orbits.
4. NEW GIANT PLANET?
If you grew up thinking there were nine planets and were shocked when Pluto was demoted five years ago, get ready for another surprise. There may be nine after all, and Jupiter may not be the largest. The hunt is on for a gas giant up to four times the mass of Jupiter thought to be lurking in the outer Oort Cloud, the most remote region of the solar system. The orbit of Tyche (pronounced ty-kee), would be 15,000 times farther from the Sun than the Earth's, and 375 times farther than Pluto's, which is why it hasn't been seen so far.
But scientists now believe the proof of its existence has already been gathered by a Nasa space telescope, Wise, and is just waiting to be analysed. See
download pdf of position diagram:
The first tranche of data is to be released in April, and astrophysicists John Matese and Daniel Whitmire from the University of Louisiana at Lafayette think it will reveal Tyche within two years. "If it does, John and I will be doing cartwheels," Professor Whitmire said. "And that's not easy at our age."
Once Tyche has been located, other telescopes could be pointed at it to confirm the discovery. Whether it would become the new ninth planet would be decided by the International Astronomical Union (IAU). The main argument against is that Tyche probably formed around another star and was later captured by the Sun's gravitational field. The IAU may choose to create a whole new category for Tyche, Professor Matese said.
The IAU would also have the final say about the gas giant's name. To the Greeks, Tyche was the goddess responsible for the destiny of cities. Her name was provisionally chosen in reference to an earlier hypothesis, now largely abandoned, that the Sun might be part of a binary star system with a dim companion, tentatively called Nemesis, that was thought responsible for mass extinctions on Earth. In myth, Tyche was the good sister of Nemesis.
Tyche will almost certainly be made up mostly of hydrogen and helium and will probably have an atmosphere much like Jupiter's, with colourful spots and bands and clouds, Professor Whitmire said. "You'd also expect it to have moons. All the outer planets have them," he added. What will make it stand out in the Wise data is its temperature, predicted to be around -73C, four or five times warmer than Pluto. "The heat is left over from its formation," Professor Whitmire said. "It takes an object this size a long time to cool off."
Most of the billions of objects in the Oort Cloud – a sphere one light year in radius stretching a quarter of the distance to Alpha Centauri, the brightest star in the southern constellation – are lumps of dirty ice at temperatures much closer to absolute zero (-273C). A few of these are dislodged from their orbits by the galactic tide – the combined gravitational pull from the billions of stars towards the centre of the Milky Way – and start the long fall into the inner solar system. As these long-period comets get closer to the Sun, some of the ice boils off, forming the characteristic tails that make them visible.
Professors Matese and Whitmire first proposed the existence of Tyche to explain why many of these long-period comets were coming from the wrong direction. In their latest paper, published in the February issue of Icarus, the international journal of solar system studies, they report that more than 20 per cent too many of the long-period comets observed since 1898 arrive from a band circling the sky at a higher angle than predicted by the galactic-tide theory. No other proposal has been put forward to explain this anomaly since it was first suggested 12 years ago.
(Caution: Don't get too carried away just yet - there's a lot of analysis still to be done, and there is no actual direct evidence of Tyche yet! T.M.)
5. GALWAY ASTRONOMY FESTIVAL: 4-6 March. The theme this year is 'Life and Death in the Universe. Venue: Westwood House Hotel, Galway. It will open with a free public lecture in NUIG about meteorite falls in Ireland on the Friday evening. See www.galwayastronomyclub.ie for full details of what looks like an excellent programme.
6. DISCOVERING THE UNIVERSE, ARMAGH, 17 March.
To mark St Patrick's Day in Armagh City, Armagh Observatory is hosting "Discovering the Universe", with two lectures in St Patrick's Trian, and a tour of the Human Orrery and Astropark in the Observatory grounds. More details on www.arm.ac.uk. Admission is free, but by ticket only. Contact Aileen at ambnarm.ac.uk
7. COSMOS 2010: The MAC Committee are working on the speaker list for this year's Cosmos Star Party. Cosmos is Ireland's second-longest running star party, since 1992 in fact, when it was first called the Irish Astrofest. This year it takes place over the weekend of April 1st to 3rd at Annaharvey, Tullamore. See the club website at www.midlandsastronomy.com for more details.
8. BCO EVENTS, CORK: Sat 26 Feb: 8pm Movies by Moonlight
We are bringing an alien invasion to our theatre but we need your help….
Should we show H. G. Wells' classic adaption of War of the Worlds (1953) or Steven Spielberg's remake (2005)? www.bco.ie/moviesbymoonlight
For more information on these and future events at Blackrock Castle Observatory
Call 021-4357917 / email infobco.ie / visit www.bco.ie/upcomingevents
9. JOINING the IRISH ASTRONOMICAL ASSOCIATION is now even easier: This link downloads a Word document to join the IAA. http://irishastro.org.uk/iaamembership.doc. See also www.irishastro.org.