The Royal Society 2075, A Space Odyssey: Magnetic Fields Across the Cosmos

In The Royal Society 2075, a Space Odyssey, Dr Kate Pattle and Prof Lucy Green explore the central role of magnetic fields across cosmic scales, from star forming clouds to the Sun’s atmosphere and the Earth’s space weather environment. They explain how magnetic fields trace structures in the interstellar medium, influence the evolution of star forming regions, discs, and jets, and how these fields are measured with polarised emission and spectroscopy. The discussion also covers solar activity, the Sun’s 11 year cycle, and how eruptions from the Sun couple with Earth’s magnetic field to affect satellites and power grids. Audience questions touch on intergalactic fields, fossil magnetism, and the implications for exoplanets and habitability.

Overview

The Royal Society hosts a discussion with Dr Kate Pattle and Professor Lucy Green on the pervasive role of magnetic fields in astronomy and heliophysics. The talk traverses magnetic fields from the scale of galaxies and star forming nebulae to the atmosphere of our Sun, highlighting how these fields influence gas dynamics, star formation, and solar activity. The session uses striking JWST images and Planck maps to illustrate how magnetic structures align with interstellar gas and dust, and how field strengths are inferred through polarisation and spectral techniques.

Magnetic Fields Across Cosmic Scales

Pattle explains that spiral galaxies host ordered magnetic fields that trace spiral arm structures, while field strengths and their dynamical importance remain uncertain. He discusses how magnetic fields can support or modify dense cores in regions like the Horsehead and the iconic Pillars of Creation, shaping how clouds evolve toward star formation, and how fields interact with feedback from young stars.

From Star Formation to Stellar Outflows

The dialogue moves to the scales of already formed stars, where magnetic fields in discs regulate jets and outflows. Green complements with solar physics perspectives, showing how the Sun’s magnetism drives eruptions and structures in the corona and wind, and how magnetic flux ropes can become eruptive.

Observational Tools and Techniques

The speakers describe the instruments that reveal magnetic fields: dust polarisation in the interstellar medium measured with far infrared observations, the upcoming Square Kilometre Array for direct magnetic field strength measurements, and space missions like JWST and Planck that map magnetic field geometries. They also touch on the limitations of mapping versus measuring field strength directly, and how simulations help interpret observations.

The Sun-Earth Connection and Space Weather

Both speakers discuss space weather, noting how solar eruptions can couple to the Earth’s magnetosphere, drive geomagnetic disturbances, and impact satellites and grids. They explain how the Earth’s own magnetic field provides shielding, and how understanding solar magnetic activity informs assessments of exoplanet habitability and planetary protection.

Audience Q&A and Future Directions

Audience questions probe intergalactic magnetic fields, primordial seed fields, and the potential fossil remnants of cloud magnetic fields. The discussion closes on the potential of next generation facilities to deliver 3D magnetic field information and improve our understanding of magnetism from clouds to planets.