\n<\/p>\n
\t\t\t\t\t\t14\/04\/2026<\/span> Since July 2025, the European Space Agency\u2019s pair of\u00a0Proba-3\u00a0satellites has already created\u00a057\u00a0artificial solar eclipses. So far, the mission has collected\u00a0more than\u00a0250\u00a0hours\u00a0of high-resolution videos of the Sun\u2019s atmosphere,\u00a0called\u00a0the corona.\u00a0That\u2019s\u00a0the same amount of\u00a0observing\u00a0time as about 5000\u00a0total\u00a0solar eclipse campaigns carried out on Earth.\u00a0\u00a0<\/p>\n But the\u00a0science is even more exciting. For the first time we can\u00a0carefully\u00a0track how material from the Sun moves through the inner corona, where\u00a0space weather\u00a0is born.\u00a0The\u00a0first results,\u00a0recently published\u00a0in\u00a0The Astrophysical Journal Letters, show that\u00a0solar wind\u00a0structures\u00a0in the inner corona\u00a0can\u00a0travel\u00a0three to\u00a0four times\u00a0faster than\u00a0scientists\u00a0thought.\u00a0<\/p>\n<\/div>\n Before Proba-3, a total solar eclipse seen from Earth\u00a0was\u00a0the\u00a0best\u00a0way\u00a0to see the Sun\u2019s inner corona. When the Moon blocks out the Sun\u2019s direct light, expert photographers can capture\u00a0beautiful details\u00a0in the atmosphere around the Sun.\u00a0But\u00a0total solar eclipses\u00a0happen\u00a0on average only once every\u00a018 months\u00a0and\u00a0totality lasts at most a\u00a0few minutes.\u00a0\u00a0<\/p>\n Proba\u20113 creates artificial total solar eclipses by flying its two spacecraft in an extremely precise formation.\u00a0For around five hours at a time,\u00a0the Occulter\u00a0spacecraft\u00a0acts like an artificial Moon\u00a0and\u00a0blocks\u00a0the Sun\u2019s\u00a0direct light\u00a0so the other spacecraft,\u00a0the Coronagraph,\u00a0can see the Sun’s corona.\u00a0<\/p>\n Proba-3\u2019s\u00a0ASPIICS coronagraph instrument\u00a0can see\u00a0down to 70 000 km from the Sun\u2019s surface, one tenth of the Sun\u2019s radius.\u00a0No other space-based coronagraph can\u00a0observe\u00a0the light scattering off particles in the Sun\u2019s corona this close to the Sun. [1] ASPIICS\u00a0takes\u00a0one or two images per minute.\u00a0These are combined\u00a0into videos that reveal never-before-seen movement in the hard-to-observe inner corona. \u201cThese\u00a0intricate\u00a0movements have\u00a0never\u00a0been observed in optical wavelengths\u00a0so low\u00a0in the Sun\u2019s inner corona,\u201d notes Joe Zender, ESA\u2019s Proba-3 project scientist.\u00a0\u00a0<\/p>\n<\/p><\/div>\n Besides light, the Sun sends out a stream of\u00a0particles\u00a0called the\u00a0solar wind. \u201cWe can track how solar wind\u00a0speeds up\u00a0close to the\u00a0Sun,\u00a0we\u00a0see it all over Proba-3\u2019s\u00a0field of view, and we have already seen speeds and accelerations\u00a0that surprised us,\u201d says Joe.\u00a0\u00a0\u00a0<\/p>\n Just like wind on Earth, solar wind can be fast or slow,\u00a0smooth\u00a0or gusty.\u00a0Fast\u00a0solar wind\u00a0usually\u00a0flows\u00a0in a smooth current from magnetic structures called\u00a0coronal holes. In contrast,\u00a0slow\u00a0solar wind is variable and gusty, making understanding how it works more difficult.\u00a0\u00a0<\/p>\n<\/p><\/div>\n Scientists think that slow solar wind is\u00a0generated by\u00a0the Sun’s\u00a0magnetic field lines\u00a0changing\u00a0how they are connected, merging and separating again.\u00a0This process pushes out\u00a0blobs of\u00a0plasma (electrically charged gas)\u00a0in so-called \u2018streamers\u2019: large, bright rays in the corona.\u00a0<\/p>\n \u201cIn the inner corona, a region\u00a0very difficult to observe, we saw slow solar wind\u00a0gusts\u00a0moving\u00a0three\u00a0to\u00a0four times faster than expected,\u201d says Andrei Zhukov\u00a0of the Royal Observatory of Belgium, the principal investigator of Proba-3\u2019s ASPIICS instrument\u00a0and the lead author of the study.\u00a0\u00a0<\/p>\n Previously,\u00a0scientists found\u00a0that\u00a0close to the Sun\u2019s\u00a0surface,\u00a0slow\u00a0solar wind should have\u00a0speeds\u00a0around\u00a0100 km\/s. Instead, Andrei\u2019s\u00a0team tracked\u00a0some\u00a0blobs of plasma moving\u00a0at\u00a0250\u2013500 km\/s.\u00a0\u00a0<\/p>\n<\/p><\/div>\n Each arrow in the graph\u00a0from Andrei\u2019s team\u00a0shows how a single blob of plasma moving through the Sun\u2019s inner corona changes its speed as it moves away from (right-pointing arrow) or towards (left-pointing arrow) the Sun. Arrows angled up show plasma blobs speeding up as they move, while down-pointing arrows show blobs slowing down. The shaded regions\u00a0show\u00a0uncertainties in the measured speeds and directions.\u00a0\u00a0<\/p>\n Overall, the wide range of speeds,\u00a0accelerations\u00a0and movement directions in the data\u00a0shows\u00a0why slow solar wind is so hard to understand. Andrei: \u201cSlow solar wind is\u00a0naturally not uniform, involving lots of small-scale structures in the Sun\u2019s magnetic field that we can see thanks to ASPIICS.\u201d\u00a0\u00a0<\/p>\n \u201cThis first dataset is just the beginning of the much longer\u00a0journey\u00a0to fully understand\u00a0what\u2019s\u00a0happening. Now\u00a0it\u2019s\u00a0up to theoretical experts to compare this to models of the magnetic field and\u00a0plasma\u00a0acceleration\u00a0in the Sun\u2019s corona,\u201d says Joe.\u00a0\u00a0<\/p>\n<\/p><\/div>\n Excitingly,\u00a0most\u00a0of\u00a0the\u00a0data collected by Proba-3\u00a0so far\u00a0is\u00a0yet to be\u00a0analysed. Scientists are invited to use\u00a0ASPIICS coronagraph data\u00a0to investigate the workings of the Sun\u2019s corona and space weather.\u00a0\u00a0<\/p>\n Key open questions\u00a0to answer are: What accelerates the solar wind? How does the Sun\u00a0fling\u00a0out material in coronal mass ejections? And why is the solar corona so much hotter than the Sun itself?\u00a0\u00a0\u00a0\u00a0\u00a0<\/p>\n<\/p><\/div>\n Proba-3\u00a0is the European Space Agency’s first eclipse-making mission. The mission consists of two satellites \u2013 the Coronagraph and the Occulter. Since\u00a0their\u00a0launch in December 2024, the satellite duo has claimed not one, but two world firsts \u2013 the\u00a0first precise formation flight, setting the mission up for\u00a0its\u00a0first artificial solar eclipse in orbit.\u00a0\u00a0<\/i><\/p>\n After having achieved\u00a0all of\u00a0its technology goals, the mission has completed more than 60 extremely\u00a0accurate\u00a0formation\u00a0flying orbits so far. Of these, 57 were dedicated to\u00a0creating artificial eclipses, allowing\u00a0the Coronagraph\u00a0to\u00a0observe the highly dynamic inner region of the Sun’s corona. By providing scientists with hours of science data\u00a0per\u00a0artificial eclipse,\u00a0Proba-3 has\u00a0accomplished\u00a0a major feat in space-based solar and heliophysics research.\u00a0\u00a0<\/i><\/p>\n Aside from\u00a0the\u00a0ASPIICS\u00a0coronagraph, Proba-3 carries two more instruments that can be used for science.\u00a0\u00a0<\/i><\/p>\n Proba-3\u2019s Digital Absolute Radiometer (DARA) instrument has been continuously measuring the Sun\u2019s energy output with unprecedented accuracy and precision. Its main goal is to investigate how much the Sun\u2019s energy output changes over time.\u00a0<\/i><\/p>\n With its 3D Energetic Electron Spectrometer (3DEES) instrument, Proba-3 is measuring the number, direction of origin and energies of electrons in Earth’s Van Allen radiation belts. This data can be used to reveal the behaviour of Earth’s radiation belts under normal conditions, and how they are affected by solar wind and coronal mass ejections.\u00a0<\/i><\/p>\n<\/p><\/div>\n \u2018Ubiquitous Small-scale Dynamics in the Slow Solar Wind Formation Region Observed by Proba-3\/ASPIICS\u2019 was published in\u00a0The Astrophysical Journal Letters\u00a0on 9 March 2026.\u00a0<\/p>\n \n[1] Other coronagraphs, such as\u00a0SOHO\u2019s LASCO\u00a0and\u00a0Solar Orbiter\u2019s Metis,\u00a0can\u2019t\u00a0observe\u00a0closer than\u00a00.7\u00a0solar radii above the Sun\u2019s surface. SOHO\u2019s\u00a0LASCO C1\u00a0coronagraph had a similar field of view to Proba-3\u2019s ASPIICS,\u00a0observing\u00a01.1 to 3 solar radii measured from the Sun\u2019s centre, but has been non-functional since June 1998. Its design meant much more stray light entered the detector; its spatial resolution was two times worse than ASPIICS; and it could only take one image every 20\u201330 minutes.\u00a0LASCO C2 and C3\u00a0are still operational and widely used for space weather monitoring.\u00a0<\/p>\n<\/p><\/div>\n
\n\t\t\t\t10<\/span> views<\/small><\/span>
\n\t\t\t\t\t\t\t\t\t\t0<\/span> likes<\/small><\/span><\/p>\n<\/header>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\n
\n\u00a0\u00a0\u00a0<\/p>\n\u2018Slow\u2019 solar wind seen speeding close to the Sun <\/h2>\n
\n\t\t\t\n\t\t<\/div>\n<\/p><\/div>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\n
\n\t\t\t\t\t\t\t\t<\/figcaption><\/figure>\nLooking forward to much more science <\/h2>\n
About Proba-3 <\/h2>\n
Notes for editors <\/h2>\n