A European spacecraft duo has discovered that the solar wind, the constant stream of charged particles from the Sun, accelerates to blistering speeds much closer to the solar surface than anyone predicted. The European Space Agency's pioneering Proba-3 mission, which began its work in July 2025, is providing the first clear tracking of how this material surges through the Sun's mysterious inner atmosphere.
## Creating an Endless Eclipse in Space
## The Unexpected Speed of Space Weather
Proba-3 is not a single satellite but a precisely flying pair. One craft holds a disc that blocks the Sun's bright face, while the other, positioned 144 meters away, records the faint, wispy glow of the outer atmosphere, or corona. Since its start, this orbital dance has already produced 57 of these artificial eclipses, amassing over 250 hours of high-resolution video. That dataset equals the total observing time from roughly five thousand eclipse campaigns conducted from Earth.
The mission's first scientific results, published in The Astrophysical Journal Letters, focus on the dynamics within the inner corona. This region is the crucible where space weather—the solar storms that can disrupt satellites and power grids on Earth—is born. By meticulously tracking the movement of structures within this plasma, scientists made a startling measurement. They found these solar wind structures racing through the inner corona at three to four times the velocity previously estimated by models.
This finding reshapes the fundamental understanding of how the solar wind gains its formidable speed. The acceleration happens remarkably fast and close to the Sun, within the very region Proba-3 was uniquely designed to study. The mission's ability to generate prolonged, pristine views of the corona from orbit has effectively removed the time constraints and atmospheric interference of ground-based observations, turning a rare celestial event into a routine laboratory experiment. For researchers forecasting the solar storms that travel toward Earth, knowing where and how quickly the wind starts its journey is a critical piece of the puzzle now falling into place.
