23 October 2015

 illustration of plasma tubes

 

 

 

 

 

 

 Image: Plasma Tubes. Image courtesy: CAASTRO, Mats Björklund.

 

Engaging the public with science can sometimes be a tricky task, but recently a discovery by a smart undergraduate student, using a new type of radio telescope and some courageous interdisciplinary research, attracted massive interest worldwide.

The ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) has seen an incredible success story unfold earlier this year as the press release for a new research paper made headlines around the world.

The paper was published under the title Real-time imaging of density ducts between the plasmasphere and ionosphere by Honours student from The University of Sydney, Cleo Loi, and members of the international consortium of the Murchison Widefield Array (MWA) radio telescope.

While it did not appear in Nature or Science, it did appear in the journal Geophysical Research Letters—which is not one of the ‘house journals’ astrophysicists commonly turn to.

A media release issued by CAASTRO titled Cosmic cinema: astronomers make real-time, 3D movies of plasma tubes drifting overhead, was a joint effort with The University of Sydney media office, the University of Toronto (for co-author Prof Bryan Gaensler) and the American Geophysical Union and was accompanied by an in-house video production.

Within the first 48 hours, the story had become the eighth most read in The Sydney Morning Herald online with 50 000 views, on news.com.au with 173 000 views and for Fairfax with 400 000 views.

Posts to the well-known and interestingly named Facebook page ‘I f*** love science’ generated over 130 000 ‘Likes’. After six weeks, the video had cracked the mark of one million views, not even counting the numerous spin-off productions on YouTube, some of which have also attracted tens of thousands of views.

One has to question: What was the key to this outstanding coverage?

As Cleo’s supervisor Dr Tara Murphy pointed out in her follow-up article in The Conversation, the answer is a combination of an amazing new telescope, a very smart student and an unexpected fusion of two areas of science—plus engaging visuals and a good ‘underdog’ story.

Cleo’s initial project was the characterisation of the ionosphere—the part of the Earth’s atmosphere, stretching between 50 and 1000 kilometres above Earth, that has been ionised by radiation from the Sun. The ionised plasma is known to affect our measurements of the positions of celestial objects, effectively shifting them around—and finding out by how much was Cleo’s task.

At her disposal was data from the MWA radio telescope in Western Australia, the low-frequency precursor instrument to the Square Kilometre Array (SKA).

Cleo’s first results showed a pattern—converging bands—in the data that none of her fellow astronomers in the collaboration could explain, some even suggested that Cleo’s data processing had introduced an error.

Ploughing through hundreds of emails over a few months, Cleo managed to test and rule out each suggestion. The first critical moment was Cleo’s insight that the bands followed the Earth’s magnetic field, and this is where geophysics came into the story. As her new collaborators from the University of Newcastle explained, a phenomenon, called ‘whistler ducts’, had been known for decades, claiming the existence of tubular structures of higher electron content than in the surrounding plasma. However, these had never been imaged. What was still unknown about the structures as seen with the MWA was their height above the ground.

The second critical moment saw Cleo solve exactly this issue, by using the signals received by MWA stations in the east and west separately to—effectively—create a giant pair of eyes to allow for stereoscopic 3D vision.

This technique revealed that the plasma tubes were hovering around 600km above Earth’s surface, which perfectly matched all predictions for whistler ducts. The MWA’s rapid snapshot capabilities further made it possible to image how the tubes formed and moved across the sky.

Realising the public interest in this discovery, CAASTRO published three short video clips of the real data, depicting the different stages of this research and the movements of these plasma tubes. Even the technical videos have been viewed almost 8000 times in the two months since publication.

CAASTRO has been producing explanatory videos for selected press releases since August 2012, with an emphasis on a clear dissemination of the science, the scientific method and its significance, along with on-camera acting by the lead author and custom-produced animations.

The amazing success of this particular video underscores the role of digital media in educating a public audience and reminds us of the importance of portraying science as engaging and scientists as human.

For more information please contact CAASTRO.

This article was kindly submitted by CAASTRO for publishing in ARChway.