1. SEDNA A new and large body has been found in the outer solar system by American astronomers. It could be as big as 2,000 km across (Pluto is 2,445 km, our Moon is 3,476 km, and Mercury is 4,878 km). It is out beyond the orbit of Pluto where such objects are very faint and they move very slowly meaning tying down its orbit is not easy but it appears to be in a very large elliptical orbit that may take 10,000 years to orbit the Sun once. It will be interesting to see if it gets called a planet or an asteroid. There was a move a few years ago (reported in our magazine) to relegate Pluto to the Edgeworth-Kuiper Belt of asteroids (a belt of minor planets found beyond the orbit of Neptune, and first proposed by the Irish astronomer Kenneth Edgeworth in 1943). The International Astronomical Union decided against this and Pluto is officially a planet, but it seems certain it did not form by the same method that the 8 major planets did and it really belongs to the EK belt. The new object has been provisionally named Sedna after an Inuit sea god. The I.A.U. would have to ratify this name to make it official. Details are sketchy as NASA is to hold a press conference today at 6pm our time and only 'leaked' details are available so far. The size of the object must have been determined by guessing its reflectivity and working out a diameter from how bright it appears so it will be open to debate as to whether Sedna is larger or smaller than Pluto. You'll no doubt hear more in tonight's news. To my knowledge the Press conference is not on NASA TV but you might 'tune in' on the net just in case (www.nasa.gov/ntv) or tune in to news services at 6pm like SKY NEWS or CNN in case they carry it live. Needless to say, the full story will be in Ireland's astronomy magazine "Astronomy & Space" (the May issue goes to press next week so sign up now on our secure server: www.astronomy.ie/sub ) 2. "HEADING TO MARS" on 2FM Dr Stuart Smith did an interview last week on the Gerry Ryan show just hours before giving our MARCH PUBLIC LECTURE. You can listen at rtsp://streaming2.rte.ie/2004/0308/08032004rte-thegerryryanshow.rm (copy and paste this in to your streaming audio player if clicking on it won't work). Go 1 hour 20 minutes in to the show to hear the interview. 3. The big sunspot continues to be visible for the first few days of this week. It split in two over the weekend if you were watching in safety through our AstroSolar filters. Comet LINEAR is gone. Mars is closest to the Pleiades star cluster this week (3 degrees on Saturday). Mercury will become visible - who will be the first in Ireland to see ALL 5 naked eye planets at once? The International Space Station starts blazing across the sky on Saturday (call our Newslines each afternoon for brief predictions: 1550-111-442 calls cost 60c/min). Full details of all these sights are in our magazine (see subscription page above). Send your reports/photos to observe@astronomy.ie for our Gallery and ObserversLog pages. ===== David Moore BSc FRAS, at Ireland's BIGGEST Telescope Shop. Tel (01) 847 0777. www.astronomy.ie info@astronomy.ie Click last line to change subscription options & see old messages: