In the show this time, Prof. Carole Mundell talks to us about the transient explosive Universe, Dr Libby Jones tells us about exploring the evolution of galaxies using dust in this month's JodBite, and your astronomical questions are answered by Dr Joe Zuntz in Ask an Astronomer.
JodBite with Dr Libby Jones
Dr Libby Jones studies astromineralogy and the chemical evolution of galaxies. In this interview, she talks about her infra-red observations of the Magellanic Clouds - small neighbouring galaxies of the Milky Way that have low metallicity and resemble distant galaxies at earlier times in the history of the Universe. The older, or evolved, stars tell us about the life cycle of dust that is produced as a star ages and then destroyed by newborn stars. The composition of this dust helps determine which materials are abundant in a galaxy, with carbon and oxygen being two particularly important ones for us here on Earth. As well as her measurements of the different types of silicate (sand) in the Magellanic Clouds, Libby tells us about making the first observations of dust-enshrouded stars in the galaxy M32 and how such stars are named.
Interview with Prof. Carole Mundell
Professor Carole Mundell works on following up gamma-ray bursts, mysterious and transient flares of gamma-rays occurring far out in the Universe. In this interview, she speaks about the likely origins of these bursts and about how they can now be rapidly followed up by telescopes operating at other wavelengths in the electromagnetic spectrum. In particular, Prof. Mundell explains how the optical Liverpool Telescope on La Palma has been equipped to make automatic observations when notified of a burst event, using instruments such as the RINGO polarimeter to take fast polarisation measurements before the radiation fades away.
Ask an Astronomer
Dr Joe Zuntz answers your astronomical questions:
- The first question is from Gerald Calia: "If light photons lack mass, why do they not escape from black holes?"
- The next question, from Dennis Rockwell, is: "Is there momentum transfer between dark and normal matter during a gravitational encounter, like there is between two bodies of normal matter?"
- Finally, Rob Peck says: "Surely the first stars formed after the Big Bang could have achieved thousands or even millions of solar masses with so much material floating around at that time. If they all spontaneously made black holes at their centres, could the supermassive black holes at the centres of galaxies be remnants of the first stars?"
Odds and Ends
Astronomers believe they may have spotted the first ever exomoon. Scientists have used a technique called gravitational microlensing to detect a system of two bodies which could potentially be a Jupiter-like planet and its accompanying rocky exomoon. Unfortunately they are unable to distinguish this scenario from the possibility that the system may simply be a dim star hosting a planet. Nevertheless, the result shows that gravitational microlensing has the potential to detect an exomoon in the near future. The original press release can be found here.
Geologists believe they have found evidence for a gigantic asteroid impact crater in South Africa. Rock fractures and spherules, which are small, round pieces of rock that form when a solid surface is liquefied and falls as molten rain, may indicate that an object more than 37 kilometres in diameter struck the Earth some 3.26 billion years ago. The impact would have been far larger than that believed to have wiped out the dinosaurs, and could even have been large enough to break up tectonic plates. There is other evidence that this period experienced a flurry of asteroid strikes known as the Late Heavy Bombardment, but with so much change on our planet since this early time in its history, it is difficult to be certain.
A paper published in the March 2013 edition Nature by Chadwick Trujillo and Scott Sheppard announced that the two astronomers had discovered an object the size of a dwarf planet in the outer Solar System. The object is currently designated 2012 VP113, but the discoverers have nicknamed it "Biden" after the Vice President of the United States. This and Sedna are the only two such objects known to exist outside the Kuiper Belt, but many astronomers anticipate that the outer Solar System will contain many similar objects. More information can be found here.
|JodBite:||Dr Libby Jones and Mark Purver|
|Interview:||Prof. Carole Mundell and Mark Purver|
|Ask An Astronomer:||Dr Joe Zuntz and Christina Smith|
|Presenters:||George Bendo, Indy Leclercq and Mark Purver|
|Editors:||Indy Leclercq and Mark Purver|
|Segment Voice:||Iain McDonald|
|Website:||Mark Purver and Stuart Lowe|
|Cover art:||Artist's impression of an 'exomoon' orbiting an extrasolar planet. Such an object may have been observed for the first time in the system MOA-2011-BLG-262, using the technique of gravitational microlensing. CREDIT: NASA/JPL-Caltech|