The magnetic field is arguably one of the most mysterious features of our planet. ESA's Swarm mission is continually yielding more insight into how our protective shield is generated, how it behaves and how it is changing. Adding yet another string to its bow, Swarm is now tracking changes in the magnetic field produced in the oceans in more detail that ever before.

Tendril of ice in the Weddell Sea

On 04 April, 2018, the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured this natural-colour image of sea ice between various levels of cloud cover. As austral autumn progresses, sea ice around Antarctica is starting to grow again after reaching its annual minimum extent on 20–21 February.