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August 2017: Summer Patchwork

August 2017

In the show this time, we talk to Dr. Caitriona Jackman about adventures in the outer Solar System, Josh Hayes rounds up the latest news, and we find out what we can see in the August night sky from Ian Morison and Claire Bretherton.

The News

Last month marked 10 years since the launch of Galaxy Zoo, a project which invites members of the public to classify galaxies in images taken by robotic telescopes across the world.
The project was launched on 11th July 2007 and had immediate success through the discovery of a new type of object called a quasar ionisation echo. Named Hanny's Voorwerp after its discoverer Hanny van Arkel, a Dutch primary school teacher, this was the first of many objects identified by the project. The count now stands at over 125 million galaxies identified, with a huge range of characteristics being seen. This output is far greater than any identification algorithm could produce and the introductory paper has had over 750 citations. Among many interesting studies conducted by Galaxy Zoo was one in galaxy rotation. Participants were asked to say whether face on galaxies were rotating clockwise or anti-clockwise. Assuming that galaxy alignment was random, the researchers were expecting roughly equal numbers of each, but found an excess of anti-clockwise rotation. The researchers investigated to see if there was a bias by showing participants the same images, but mirrored and found that there was still a bias towards (incorrect) anti-clockwise identification! When correcting for this, it was found that spiral galaxies which are near to each other have a tendency to rotate inexoplanets and discover new pulsars. They have even branched out beyond astrophysics and the power of the public is now being used to to count giraffes and elephants, transcribe Shakespeare's handwritten documents and identify parts of cells. Here's to another, even more successful decade of citizen science!

Measurements from an Indian lunar orbiter have suggested that the levels of water ice below the Moon's crust are much higher than previously thought. Launched in 2008 and operated until 2009, the Chandrayaan I spacecraft has revealed that whilst the majority of the lunar surface has only background levels of water, there are some regions with an excess when compared to this background. Further study of these areas shows that all of them are associated with material ejected from below the surface by a volcano, known as pyroclastic deposits. Since these rocks were formed below the surface, they can be used to infer the composition of the lunar mantle without having to drill down through the crust. The high level of water seen in these pyroclastic rocks is thought to mean that there is more water under the surface of the moon than previously thought. This has led to some discussion of further manned missions to the moon to collect samples from the pyroclastic deposits or extract water from below the lunar surface. (Item contributed by Antonia Newell.)

A team of Japanese scientists have completed an investigation into the effects of gravity on plant growth by successfully growing cucumbers on board the ISS. The experiment was designed to discover if gravity or water has a greater impact on root growth. On Earth, there are two effects which govern root growth: hydrotropism, where roots grow towards high concentrations of water; and gravitropism, where the roots grow in the direction of the pull of gravity. By growing cucumbers on the ISS, the effects of microgravity could beinvestigated. The experiments showed that hydrotropism has a greater influence in controlling root growth. This could have interesting impacts on long distance space travel, as it would appear that in order to grow plants well, we only need to use water concentration gradients and can manage without strong gravity. This discovery is an important one in the steps towards long-term space habitation.

Interview with Dr. Caitriona Jackman

Monique interviews Dr. Caitriona Jackman from the University of Southampton about her extensive involvement with both the Juno and Cassini missions, active around the giant planets Jupiter and Saturn respectively. Among the discussion are UV aurorae, the perils of space weather, the mystery of what Jupiter's core is like and the correct way to sniff a Saturnian moon.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the northern hemisphere night sky during August 2017.

The Planets

Southern Hemisphere

Claire Bretherton tells us what we can see in the southern hemisphere night sky during August 2017.

Kia ora and welcome to the August Jodcast from Space Place at Carter Observatory in Wellington, New Zealand.

The Planets

Odds and Ends

This month in the Odds and Ends we discuss a recent paper which points out some potential errors in the LIGO collaboration's data analysis of their gravitational wave detections, which were announced last year.

The paper, which has become colloquially known as 'The Danish Paper' appeared on the arXiv on the 13th of June and set off an interesting chain of events, both from a scientific and sociological perspective. A blog post on the Forbes news website by Sabine Hossenfelder created a large amount of interest in the paper, and the potential that it was calling into question a Nobel Prize-worthy finding in astrophysics. However, a rejoinder from a member of the LIGO collaboration in another blog post pointed out a number of issues with the Danish Paper itself, with the detailed fallout still continuing.

Ian, Monique and Charlie discuss the content of the Danish Paper and it's rebuttal, and the impacts it may have on how science is communicated with the public.

Additional Caveat from Ian: This was recorded on the 20th of July. There has been subsequent revision of 'The Danish Paper' by the authors, taking into account comments from journal referees. The situation is still evolving (along with our understanding and opinions!) and it is left to the listener to judge whether we are too quickly jumping to conclusions in our discussion, we apologise if this seems so.

Show Credits

News:Josh Hayes
Interview:Dr. Caitriona Jackman and Monique Henson
Night sky:Ian Morison and Claire Bretherton
Presenters:Ian Harrison, Monique Henson, Charlie Walker
Editors:Ian Harrison, Adam Avison, Claire Bretherton, Parvin Mansour, Tom Scragg, Charlie Walker
Segment Voice:Iain McDonald
Website:Jake Morgan and Stuart Lowe
Producer:Jake Morgan
Cover art:A summer patchwork! CREDIT: Glenys Gaske, via Wikimedia Commons

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