Recently, Codex (Coronal Diagnostic Experiment), a coronograph installed on board the international space station in November 2024, transmitted its first images, revealing structures invisible to the naked eye and aroused surprise both among specialists and the general public.
The instrument works by blocking sunlight using a blackout disc, like the moon during a total eclipse, This makes it possible to observe the solar crown, the fine external atmosphere which extends over millions of kilometers in space. It is in this region that the solar wind is born which reaches the earth, a key element of the space weather.
These images reveal filaments and structures called streamsplasma flows guided by solar magnetic fields. Until now, we could only observe the density of these regions, but Codex goes much further: it provides data on temperature and speed – essential parameters to understand the energy processes of our star.
Its installation on the ISS was made possible thanks to the robotic arm of the station, which placed it precisely on its observation platform. Its position allows it to scrutinize the sun for almost 90 minutes each orbit, Collecting an unprecedented volume of data and revolutionizing the science of the heliosphere.
Temperatures and speeds never observed before
The new images are not simple photographs: these are thermal and speed cards. Thanks to the use of four special filters – two to detect the temperature and two to estimate the speed – it is possible to make simultaneous diagnoses by analyzing the dispersion of the light by the electrons of the solar crown.
The preliminary results show that the solar wind does not flow as a uniform jet, But in the form of irregular gusts of plasma. This turbulence can influence its interaction with the terrestrial magnetic field and play a role in the formation of geomagnetic storms, which can affect technologies and electrical networks.
Moreover, Temperature gradients have been detected in the solar crown, where certain regions exceed the million degrees Celsius – A temperature much greater than that of the surface of the sun. This discovery reinforces the theory that magnetic processes transfer energy to coronal plasma, shedding new light on a mystery that has intrigued scientists for decades.
said NASA’s researcher Jeffrey Newmark.
With these first data, A new era opens for the exploration of the crown and the solar wind from space.
A key element to understand the space weather
Why is it so important to measure temperature and speed in the solar crown? The answer lies in the space weather: The solar wind impacts satellites, electrical networks and astronauts. Knowing your behavior from its origin therefore makes it possible to anticipate your variations and better protect technologies essential to modern life on earth.
Codex completes other missions such as Parker Solar Probe, which directly measures plasma near the sun, and Solar Orbiter, offering a multidimensional vision of our star. For the first time, it is thus possible to observe from several angles the birth and the evolution of solar flows which cross the solar system.
These discoveries will be decisive during the current solar cycle 25, which will reach its maximum around 2025-2026, A period during which solar ejections and storms are more frequent and more powerful, increasing the risks for communication, navigation and electrical supply infrastructure on a global scale.
The scientific community can now test the physical models describing how the sun heats its crown and accelerates the solar wind up to almost a million kilometers per hour – A still unresolved mystery, now discussed thanks to innovative space technology and high -resolution observations.
A new look at the sun and its secrets
The impact goes beyond the framework of solar physics: The technique of creating artificial eclipses and the advanced filters used could, in the future, be applied to the study of other stars and their environment. What is most remarkable is that this mission demonstrates the capacity of the international space station to host advanced experiences dedicated to basic research.
Soon, continuous observation campaigns will be carried out, producing detailed cards which will make it possible to compare the results with those of other coronographers such as Soho/Lasco, as well as with the future satellites of the Noaa and NASA. This synergy will lead to the creation of a global model of the solar wind and its influence on the heliosphere.
Thus, this little instrument becomes a giant of solar research, offering us the opportunity to contemplate with a new eye the invisible atmosphere that surrounds our star and regulates our space environment here below, influencing everything, communications with space flights.
1/3
ALERT! New views of the Sun just dropped! ️During a press briefing today, scientists revealed the first images from NASAs Coronal Diagnostic Experiment, or CODEX mission. Mounted outside the International Space Station, CODEX blocks out bright light from the Sun to pic.twitter.com/pbhEqGo6d0
— NASA SUN & SPACE (@nasacun) June 10, 2025
Heliospheric science enters a new era thanks to Codex and its images, which, combined with those of other missions, will answer fundamental questions about the extreme heat of the solar crown and solar wind dynamics.
The years to come and promise to be promising, with discoveries that will transform our vision of the King Astre.
