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November 2014 Extra: Pulsars and Comets Everywhere

November 2014 Extra

In the show this time, we talk to Dr. Scott Ransom about the International Pulsar Timing Array, Sally Cooper tells us about hunting pulsars with the LOFAR telescope in this month's JodBite, and your astronomy questions are answered by Dr. Joe Zuntz in Ask an Astronomer.

JodBite with Sally Cooper

Sally Cooper is a PhD student at the Jodrell Bank Centre for Astrophysics, and she hunts pulsars using the LOFAR telescope. She explains what pulsars are, why we want to find more of them and why LOFAR is a special instrument for doing so. She also talks about training computers to recognise the signature of a pulsar in the huge amount of data generated by LOFAR, and discusses why the human touch is still important in the process. Finally, she describes how it feels to discover a pulsar for the first time.

Interview with Dr. Scott Ransom

Dr. Scott Ransom works at the National Radio Astronomy Observatory in Charlottesville, Virginia where he studies pulsars in all their various forms. In this interview, he talks about the International Pulsar Timing Array, a global project using the largest radio telescopes in the world that measures the timing of the signals from of a group of millisecond pulsars (MSPs) to extremely high accuracy. The ultimate aim of this project is to use a group of MSPs as a galaxy-sized sensor array for detecting ultra-low frequency gravitational radiation - the ripples in the fabric of space-time as predicted by Einstein. Dr. Ransom tells us how these MSPs are found and timed to such high precision and how they can be used as tools to probe fundamental physics.

Ask an Astronomer

Dr. Joe Zuntz answers your astronomical questions:

Odds and Ends

Humanity's first landing on a comet happened with a bump on the 12th of November. Philae, armed with an array of scientific instruments and the ability to drill into Comet 67P/Churyumov-Gerasimenko, will now look for organic molecules and help to show whether they originated in the nucleus or the tail. However, by the time of release of the Jodcast, it had been revealed that Philae initially bounced on the surface before coming to rest in the shadow of a cliff, which may prevent it from using its solar panels to recharge itself.

For the first time, a comet has been observed from another planet. Comet Siding Spring flew by Mars on October 19th, and three spacecraft were there to witness it: the Mars Express, the Mars Atmosphere and Volatile Evolution mission, and the Mars Reconnaissance Orbiter. The comet originated from the furthest reaches of our solar system, the Oort Cloud, and came as close as ~140,000 km, which is a tenth of the distance that any comet has ever approached Earth. This close encounter strongly affected the martian atmosphere, as dust from the tail produced intense meteor showers that interacted with magnesium and iron ions in the atmosphere, emitting ultraviolet radiation in the process. Unique observations have been made of the comet during this encounter. The size of the nucleus was smaller than expected, but the rotation period matched predictions. The composition of the dust from the tail was also analysed, which had not previously been done for an object coming from somewhere as distant as the Oort Cloud. More information can be found from here.

On November 5th, the ALMA telescope released a press release showing a spectacularly high-resolution image of planet formation in action around the young star HL Tau, located some 450 light years away. Made while observing at a frequency of 233 GHz, the image was part of the Long Baseline Campaign, part of ALMA's Science Verification process, where new capabilities of the array are tested before being offered to the scientific community. By observing with antennas spread over distances up to 15 km, the resolution of the telescope is improved significantly, producing images with stunning detail.

Show Credits

JodBite:Sally Cooper and Mark Purver
Interview:Dr. Scott Ransom and Indy Leclercq
Ask An Astronomer:Dr. Joe Zuntz and Monique Henson
Presenters:Megan Argo, Josie Peters and Mark Purver
Editors:Sally Cooper, Monique Henson, Cristina Ilie, and Ben Shaw
Segment Voice:Tess Jaffe
Website:George Bendo and Stuart Lowe
Producer:George Bendo
Cover art:An artist's conception showing NASA's Mars orbiters and Comet Siding Spring (C/2013 A1). CREDIT: NASA/JPL-Caltech

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