Space and Physics
PUBLISHED
The European Space Agency’s Proba-3 is a marvel of engineering. Two spacecraft fly in formation to observe the Sun. Well, not exactly the Sun, but its atmosphere: the corona. The two spacecraft get into an alignment so that the one that is Sun-side blocks the solar disk as it happens during a solar eclipse, while the one behind instead looks at the emission of the corona.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.In observations collected on September 21, 2025, the spacecraft snapped not one but multiple eruptions in the solar corona. Matching Proba-3 observations with NASA’s Atmospheric Imaging Assembly (AIA) aboard NASA’s Solar Dynamics Observatory, we can now see the process as a whole.
“The corona is extremely hot, about two hundred times hotter than the Sun's surface,” Andrei Zhukov from the Royal Observatory of Belgium, Principal Investigator for the ASPIICS coronagraph aboard Proba-3, said in a statement.
“Sometimes, structures made of relatively cold plasma (charged gas) are observed near the Sun – although these are still around 10 000 degrees Celsius, they are much colder than the surrounding million-degree hot corona – creating what we call ‘a prominence’.”
Due to the formation flying, Proba-3 is not always under “eclipse” mode. The observations window this time was five hours, with images collected every five minutes. Still, it was a surprisingly exciting five hours.
“Seeing so many prominence eruptions in such a short timeframe is rare, so I’m very happy we managed to capture them so clearly during our observation window,” added Zhukov.
Proba-3 will observe the Sun during the total solar eclipse happening between Iceland and Spain this coming summer, and the results will be compared. A natural eclipse can get a lot more detail, but clearly, Proba-3 is doing some pretty good work.
