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December 2011: Sparky

December 2011

In this show, we talk to Dr Sonia Anton about quasars and the Gaia mission and we find out about a mysterious radio signal from an old Jodcaster, Dr Evan Keane. As always, Megan rounds up the latest news and we hear what we can see in the December night sky from Ian Morison and John Field.

The News

In the news this month:

Interview with Dr Sonia Anton

Stuart talks to Dr Sonia Anton (Porto University) about how a new mission to study the Milky Way can help us to understand distant quasars. Gaia is an ESA mission scheduled for launch in 2013 that is designed to map the Milky Way with microarcsecond precision. In order to know which direction it is pointing, Gaia will use quasars as reference points because the positions of quasars are already known to very high accuracy through VLBI radio observations. In this interview, Sonia tells us about quasars (and blazars) and the Gaia mission before explaining how she hopes to use data from Gaia to investigate "jitters" in the optical positions of quasars.

Interview with Dr Evan Keane

In this interview, former Jodcaster Dr Evan Keane (now of the Max Planck Institute for Radio Astronomy) talks to Liz and Mark about a radio burst that was observed using the Parkes Telescope in Australia. This burst initially looked like an single pulse from a pulsar, but more evidence showed that this was not the case. The emission did not occur again, and so far its source has not been identified. The distance to the burst was estimated using the dispersion measure, which indicated that it originated from outside of our Milky Way, making it similar to the Lorimer burst found a few years ago. One of the possibilities is that this radio burst was produced by the evaporation of a mini black hole, so Evan explains this theory to us.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the northern hemisphere night sky during December 2011.

The summer constellations of Cygnus and Lyra are still visible high in the north-west in the evening, with their bright stars Deneb and Vega. The Milky Way arcs overhead from Cygnus. The Square of Pegasus is in the south, while the winter constellations of Taurus and Orion follow from the east. The Pleiades star cluster lies in Taurus, and in the centre a telescope reveals a triplet of stars and a double star system nestled among the brighter members. Below Orion's Belt, the nebula M42 makes up part of Orion's Sword. The stars of the Trapezium can be seen within the nebulosity using a telescope. Sirius, the brightest star in the sky, rises to the lower left of Orion later in the evening. Above and left of Orion and Taurus is Gemini with its twin bright stars Castor and Pollux. Leo rises late in the night.

The Planets


Southern Hemisphere

John Field from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during December 2011.

The constellations of Taurus, Orion, Canis Major and Canis Minor are in the northern sky in the evening. The fainter summer constellations of Hydrus, Mensa and Volans cluster around the south celestial pole. The ninth-brightest night-time star, a blue giant named Achernar, is high in the winding constellation of Eridanus, the River. It is not spherical, but is flattened by its high rotational speed. Hydrus, the Water Snake, contains three bright stars, each of around magnitude +3, in a triangle which crosses the constellation of Tucana and the Small Magellanic Cloud. Pi Hydri is a double star of magnitude +5.5, consisting of unconnected red and yellow stars. Mensa, the Table, contains no stars brighter then magnitude +5, but it is home to part of the Large Magellanic Cloud, the most massive dwarf satellite galaxy of the Milky Way, in which star clusters and nebulae can be seen with binoculars or a small telescope. The star Pi Mensae is orbited by a planet of around 10 times the mass of Jupiter. Volans, the Flying Fish, contains a double star called Gamma Volantis in a field of scattered stars.

The rich star fields of Carina, along the Milky Way, contain the asterism of the Diamond Cross and the open cluster IC 2602, known as the Southern Pleiades. The cluster contains over 30 stars, the brightest of which is Theta Carinae at magnitude +2.8. On the other side of the Diamond is another open cluster, NGC 3532, or the Wishing Well Cluster, which spans twice the area of the full Moon. The Carina Nebula, at the heart of which is the immense star system of Eta Carinae, is in the same constellation. Crux, the Southern Cross, is further south along the Milky Way, small but very visible. The dark and dusty cloud of the Coalsack Nebula runs alongside, and is a place where stars of the future will be born.

The Planets


Odds and Ends

The White House has responded to a petition asking the Obama Administration to "formally acknowledge an extraterrestrial presence engaging the human race". Surprisingly enough, the answer from the White House is that there is no evidence for contact with aliens.

An article in the Astrobiology journal has ranked the habitability of other planets and moons. The top candidates include Saturn's moon Titan and the extrasolar planet Gliese 581g.

An article to appear in the December edition of the Communicating Astronomy with the Public journal has appeared on the arXiv analysing the misuse of lunar images in Christmas cards and wrapping paper. The author points out that many Christmas cards depict a waning crescent Moon which would mean that children would be out decorating Christmas trees in the early hours of the morning.

Stargazing Live returns to the BBC on January 16 - 18 and we assume will feature Jodrell Bank again.

If you're thinking of getting a telescope for Christmas, check out Ian Morison's telescope advice page (there's also one for binoculars).

Show Credits

News:Megan Argo
Interview:Dr Sonia Anton and Stuart Harper
Interview:Dr Evan Keane, Liz Guzman and Mark Purver
Night sky:Ian Morison and John Field
Presenters:Melanie Gendre, Jen Gupta, Liz Guzman and Mel Irfan
Editors:Mark Purver, Megan Argo, David Ault, Claire Bretherton, Liz Guzman and Stuart Harper
Intro/outro script:David Ault
Narrator:Libby Jones
Jenderella:Jen Gupta
Baron Cardiff:Stuart Lowe
Stepmother:Melanie Gendre
Ugly Sisters:Adam Avison and Mark Purver
Fairy Jodmother:Megan Argo
Prince Professional Respect:David Ault
Extras:Leo Huckvale and Christina Smith
Segment Voice:Mike Peel
Website:Jen Gupta and Stuart Lowe
Producer:Jen Gupta
Cover art:The first image from e-Merlin, showing the "Double quasar". CREDIT: Jodrell Bank Centre for Astrophysics

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