Orbiting spacecraft such as NASA’s Solar Dynamics Observatory and STEREO also have the potential to delve into the structure of the sun’s outer layers, albeit by probing different wavelengths. Still, ALMA is not the only window onto the coronal heating mystery. ‘It’s difficult to say exactly when we will make a breakthrough, but it will come,’ said Dr Wedemeyer. But Dr Wedemeyer points out that the challenge brings a greater reward, as he and his colleagues will be able to generate not just solar images, but solar movies.įrom data collected in December 2016 and April last year, the researchers are using their tools to create their first images and movies of fibrous heat structures changing in the sun’s outer atmosphere. Similar tools have been developed before, for the study of nebulae and other astrophysical entities, but they have only been required to track changes over long periods of time.įor an object like the sun, which changes minute by minute, the task of developing the tools is a lot harder. In principle, each of these colours give an insight into the structure of the sun at different depths, like peeling away the layers of an onion.ĭr Wedemeyer’s job is to devise the computational tools to convert ALMA’s raw data into this sort of 3D temperature map. ‘Which mechanism contributes the most to the deposition of energy?’Ĭonsisting of 66 radio antennas spread out over up to 16 kilometres, ALMA can study the sun’s various wavelengths – similar to the different colours in visible light – of heat radiation at unprecedented resolution.

‘Today, the question is not how the heat gets there, but how exactly?’ explained Dr Wedemeyer. We keep adding small pieces all the time.’ Professor Ineke De Moortel, University of St Andrews, UK Some scientists believe the heat is transported there by acoustic waves, while others believe the heat is generated by the snapping of magnetic field lines – a similar phenomenon to that behind solar flares.īut no one knows if just one of these ideas is responsible, or if they are all involved in varying amounts. Nowadays, there are many theoretical ideas for how so much heat ends up in the corona. He is working on a project called SolarALMA, funded by the EU's European Research Council (ERC) to analyse groundbreaking data from the Atacama Large Millimeter/submillimeter Array (ALMA), an expansive radio observatory in northern Chile’s Atacama Desert. The reason is a mystery, but now some scientists believe they’re on the verge of finding out.ĭr Sven Wedemeyer of the University of Oslo in Norway is one such scientist. In fact, way out in the sun’s corona (the outermost part of its atmosphere) the temperature rises swiftly – to several million degrees. But you might think that, like a fire, the temperature drops as you move away from the surface.

Sun corona temperature celsius