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March 2012: Flat-packed

March 2012

In this LOFAR-themed episode, we talk to Dr Neal Jackson about the Low Frequency Array itself, Dr Tom Hassall tells us about using it to detect pulsars and Anna Kapinska discusses how it can be used to study active galactic nuclei. Megan rounds up the latest news and we find out what's in the March night sky from Ian Morison and John Field.

The News

In the news this month:

Interview with Dr Neal Jackson

Dr Neal Jackson from the University of Manchester talks us about a new array of low frequency radio telescopes called LOFAR. He discusses why LOFAR looks so unusual compared to other telescopes and why LOFAR could never have been done before the modern day. He proceeds to tell us about his own interests for LOFAR and gives an overview of some of the other key science projects.

Interview with Dr Tom Hassall

Libby caught up with Dr Tom Hassall a former PhD student from JBCA and now a postdoctoral researcher at the University of Southampton who is working on pulsars and radio transients. In this interview Tom talks to us about using LOFAR to detect pulsars, and how pulse profiles change with height above the pulsar.

Interview with Anna Kapinska

Anna Kapinska from the University of Portsmouth talks to us about radio galaxies and active galactic nuclei. She mentions the black holes in the centre of these galaxies, the jets being created and the lobes which can be observed. Similar jets to these may be produced in stellar-mass black holes, and Anna tells us the benefits of observing these objects. Anna also talks about the peculiar object SS433, which has a very interesting structure.

She also tells us about her newer work with LOFAR, automating imaging with the array in collaboration with The University of Bonn.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the northern hemisphere night sky during March 2012.

Orion begins to set around sunset, with Taurus and the Pleiades Cluster above it in the southern sky. Above and left, the stars Castor and Pollux form the heads of Gemini, the Heavenly Twins. Nearby is Cancer, which contains the Beehive Cluster, M44. Further east lie Leo and the planet Mars, while Saturn rises in Virgo as the evening progresses. Ursa Major, high up in the north, hosts many nice objects, and, to its east, the bright star Arcturus rises in the constellation of Boötes.

The Planets

Highlights

Southern Hemisphere

John Field from the Carter Observatory in New Zealand speaks about the southern hemisphere night sky during March 2012.

The summer constellations of Taurus, Orion and Gemini slide towards the western horizon as the nights lengthen. The Pleiades, or Matariki, will soon disappear from the evening sky and will reappear in the midwinter mornings. The bright, orange star Aldebaran is one of the eyes of Taurus the Bull and follows the Pleiades. It is a red giant and, from our viewpoint, sits among the more distant Hyades Cluster which forms the rest of the Bull's head. Cancer the Crab is almost due north in the early evening, and contains the Beehive Cluster at its centre. This cluster is larger than the Moon on the sky, and its age and velocity suggest a shared history with the Hyades. Leo the Lion rises at sunset and follows Cancer across the sky. Its brightest star, Regulus, has an 8th-magnitude companion that can be viewed with binoculars or a telescope.

Mars is currently in Leo and reaches opposition on the 3rd of March, when it is on the opposite side of the sky to the Sun and is making a close approach to Earth. Mars's day is slightly longer than Earth's, allowing different parts of the planet to be observed at the same time on successive nights, and features such as the north polar cap can be seen. Saturn rises around 10pm at the beginning of the month and around 8pm at the end, appearing as a bright yellow 'star' in the constellation of Virgo.

The Milky Way runs from north to south in the evening sky, becoming brightest near the southern horizon. Our eyes can pick out some 6000 of the Galaxy's 400 billion or so stars, and the Milky Way is the combined light from many of those that we cannot resolve. To the Māori in Aotearoa, it is Te Ikaroa - the Long Fish - and is the path taken by Tama-rereti as he placed the stars into the heavens. The Milky Way is mottled by dark clouds of interstellar material that block the more distant starlight. Crux, the Southern Cross, is in the southern region of the Milky Way. Between Crux and Canis Major lies the former constellation of Argo. In 1752, this great ship was broken into three parts: Carina, the Keel; Vela, the Sails; and Puppis, the Poop Deck. Malus, the Mast, became Pyxis, the Compass. Carina contains the night sky's second-brightest star, Canopus, shining at magnitude -0.72. In Greek mythology, Argo carried Jason and the Argonauts in their quest to find the Golden Fleece, and Carina, its hull, points towards the south celestial pole.

The 20th of this month marks the autumnal equinox, when day and night are of almost identical length and the Sun moves from due east to due west during the day. In Mā legend, Te-Rā - the Sun - had a summer wife call Hine-Raumati and a winter wife called Hine-Takurua. From the time of the summer solstice he begins moving from Hine-Raumati to Hine-Takurua, and begins to journey back again from the point of the winter solstice.

Odds and Ends

In January, stormy weather damaged the LOFAR station at Chilbolton, UK. This telescope is unusual as it was constructed by volunteer astronomers from nearby LOFAR-UK Universities. The Jodcast went along to help out on the repair day which included replacing the damaged antennas and securing the others.

Neutrinos may not travel faster than light after all, but it isn't a sure thing yet. The OPERA Collaboration caused a stir in September 2011 by announcing that they had measured muon neutrinos moving with superluminal speed, breaking the rule of Einstein's special theory of relativity that says that no particle with mass can travel at or above the vacuum speed of light. After an exhaustive search, the team has now come up with two possible sources of error. The first is a connection in the optical fibre used to carry a GPS signal to one of the clocks in the underground experiment; the signal is needed to synchronise the clocks at either end of the neutrinos' path, and an incorrect measurement of its travel time through the fibre may mean that the neutrinos weren't going faster than light after all. The second is an oscillator recording the GPS synchronisation times, but this erred in the opposite direction and may mean that the neutrinos really were breaking the light barrier.

The Hubble Space Telescope has been used to confirm that the planet GJ1214b is a so called water-world. GJ1214b was discovered by a ground-based telescope in 2009 and was found to have a diameter 2.7 times that of Earth. However, with a mass just 7 time that of Earth, it has a much lower density than our own planet. Water on this planet may behave in very unfamiliar ways due to the planet's temperature and atmospheric pressure, leading to exotic things like 'hot ice' and 'superfluid water'.

Show Credits

News:Megan Argo
Interview:Dr Neal Jackson, Stuart Harper and Mark Purver
Interview:Dr Tom Hassall and Libby Jones
Interview:Anna Kapinska and Christina Smith
Night sky:Ian Morison and John Field
Presenters:Adam Avison, Libby Jones and Mark Purver
Editors:Mark Purver, Megan Argo, Claire Bretherton, Mel Irfan, Libby Jones and Dan Thornton
Segment Voice:Kerry Hebden
Website:Libby Jones and Stuart Lowe
Producer:Libby Jones
Cover art:Lunar eclipse over a LOFAR station CREDIT: Megan Argo

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