March 2024 : Feel the Magnetic Pull

Episode Audio

Feel the Magnetic Pull. In this episode, Jessy Marin talks to Dr. Kate Pattle about her work studying the involvment of magnetic fields in star formation. We discuss some of the newly released images from the Event Horizon Telescope and JWST and test a new format for our Odds and Ends section where we present an interesting article on Saturn's moon Mimas.

The News

Scientists using the Event Horizon Telescope have produced a new image of the black hole M87 – and it’s looking a little different this time. The first ever direct image of a black hole was made using the Event Horizon Telescope – an interferometer which combines antenna on multiple different contents to produce what’s effectively a planet-scale telescope – back in 2019, and showed a firey ring of accreting material over 50 million light years away. The original image was made using data collected up until 2017, while a newly-released image incorporates an extra year of data. While it shows broadly the same structure and shape, it has been observed that the brightest region of the “ring” has rotated by about thirty degrees. This isn’t unexpected behaviour – black holes are expected to rotate, just as the galaxies that surround them do – but this is visual confirmation thanks to material around the black hole. This new image is also sharper than the 2019 original because the EHT itself has gotten bigger: the Greenland Telescope has joined the telescope array, providing additional interferometric baselines and allowing for finer detail to be observed.

In other news (also featuring incredible pictures) is the public release of James Webb images of 19 spiral galaxies. These images were taken as part of the PHANGS project, which aims to observe galaxies across multiple wavelengths using a variety of instruments: ALMA, Hubble Space Telescope, Very Large Telescope. The JWST’s Mid Infrared Instrument (MIRI) is useful to map dust along filaments, indicating high star formation rates. MIRI also observed holes in the interstellar dust, produced by exploding stars. The near infrared camera (NIRCam) observes the distribution of stars throughout the spiral arms and within star clusters. Observing galaxies at a variety of wavelengths can help to understand formation mechanisms & galaxy dynamics

Interview with Dr. Kate Pattle

Jessy interviews Dr. Kate Pattle and they discuss the role of magntic fields in star formation as well as the methods used to measure these using ground-based telescopes. They also discuss Dr. Pattle's involvement in writing a chapter in Protostars and Planets 7.

Odds and Ends

A planetary ocean has been discovered hidden under the icy surface of Saturn’s moon Mimas, as reported in a recent Nature paper. While not the first oceanic moon discovered in our solar system (another of Saturn’s moons, Europa, has been known to have a similar ocean for a number of years) it is somewhat unusual because Mimas’s ocean formed very recently in geological terms: only twenty-five million years ago at the oldest, and it might be as young as two million years old. We discuss how the ocean’s presence was confirmed, the benefits of continuing to study the planets and moons within our solar system, and what we might learn from such a recently formed ocean.

And now on to feedback.

This month’s feedback comes from emails to our website:

Mark Warwicker wrote, "Good to have you back - brilliant & thank-you. Will Ian Morrison's monthly night sky guide be returning?"

Mark Foskey wrote, "I can't tell you what a warm feeling I got when I heard your cheerful theme music coming over my earbuds. I hope you can get enough momentum to keep it going!"

As you think about modernizing it, one thing I hope you won't change is the way you interview lots of working astrophysicists (including students) on the work they happen to be involved in right then. It's fun to get a view of research as it is going on.

And a big thank you to everyone else who’s been writing in to say welcome back!

Show Credits

News : Fiona Porter, Lousia Mason and Bijas Najimudeen
Interview : Kate Pattle and Jessy Marin
Night Sky : Fiona Porter, Lousia Mason and Bijas Najimudeen
Presenters : Fiona Porter, Lousia Mason and Bijas Najimudeen
Editors : Lily Correa Magnus, George Bendo and James Turner
Segment Voice : Lily Correa Magnus and George Bendo
Website : Lily Correa Magnus & George Bendo
Producer : Louisa Mason, George Bendo and Lily Correa Magnus
Cover Art : The Tarantula Nebula in the Large Magellanic Cloud with superimposed streamlines showing the magnetic field morphology from the SOFIA HAWC+ polarization maps. CREDIT:ESO, M.-R. Cioni/VISTA Magellanic Cloud survey, Cambridge Astronomical Survey Unit, NASA/SOFIA.