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November 2013 Extra: Momentous

November 2013 Extra

In the show this time, Dr Adam Deller tells us about a new high-resolution radio survey, Peter Schemmel talks about experimenting with the orbital angular momentum of light in this month's JodBite, and your astronomical questions are answered by Dr Mark Purver in Ask an Astronomer.

JodBite with Peter Schemmel

Peter Schemmel is a PhD student at the Jodrell Bank Centre for Astrophysics, conducting experiments to investigate the orbital angular momentum (OAM) of light. He explains the physical meaning of light with orbital angular momentum, and discusses how researchers are developing ways to detect it at low (microwave) frequencies. As Peter explains, telescope receivers may one day measure the orbital angular momentum of the light they collect, in order to gather new information about astronomical objects.

Interview with Dr Adam Deller

Dr Adam Deller, a radio astronomer at ASTRON in the Netherlands, talks to us about a new very-high-angular-resolution radio survey called mJIVE. The survey makes use of an technique called Very Long Baseline Interferometry (VLBI), which combines measurements from telescopes that can be separated by thousands of kilometres to form images with an angular resolution of a few milli-arcseconds (around a millionth of a degree!) at a frequency of 1.4 GHz. He explains how such a high-resolution survey has recently been made possible thanks to a technique that drastically reduces the volume of data by looking only at pre-selected regions. Finally, he talks about some early results with mJIVE, most notably the discovery of new candidate gravitational lenses.

Ask an Astronomer

Dr Mark Purver answers your astronomical questions:

Odds and Ends

India launched its first mission to Mars on 5 November 2013. The Mars Orbiter Mission (MOM), also known as Mangalyaan, entered a highly elliptical orbit around the Earth ahead of six engine thrusts designed to swing it ever higher before flinging it off towards the Red Planet. Although the fourth of these thrusts did not lift the spacecraft as high as expected, spare fuel allowed the problem to be resolved with an extra boost that was executed after this episode of the Jodcast was recorded. MOM, which cost just $72 million (£45 million), will encircle Mars in 10 months' time and probe the Martian atmosphere, investigating why the planet lost its water.

During a five-hour spacewalk on the International Space Station, Russian cosmonauts handed over the Olympic torch as part of the torch relay for the Sochi 2014 Winter Games. This is the first time an Olympic torch has been taken out into open space, although Olympic torches have travelled aboard spacecraft twice before.

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite fell to Earth south of South America on 11 November 2013. The satellite had been orbiting Earth since March 2009, performing highly precise measurements of variations in the Earth's gravitational field. To do this, the satellite needed to orbit the Earth at an altitude of 260 km, which was low enough that it encountered some drag from the upper portion of the Earth's atmosphere. The satellite had used propellant to keep it in orbit, but it ran out of propellant on 21 October and finally (and ironically) succumbed to gravity this month.

Show Credits

JodBite:Peter Schemmel and Mark Purver
Interview:Dr Adam Deller and Indy Leclercq
Ask An Astronomer:Dr Mark Purver
Presenters:George Bendo, Libby Jones and Mark Purver
Editors:Adam Avison and Mark Purver
Segment Voice:Mike Peel
Producer:Mark Purver
Website:Mark Purver and Stuart Lowe
Cover art:The phase pattern of light with 'mode 1' orbital angular momentum. CREDIT: Peter Schemmel, JBCA

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