Scientists are now creating artificial solar eclipses in space, offering an unprecedented look at the Sun's mysterious outer atmosphere. The European Space Agency's (ESA) Proba-3 mission, launched in December 2024, recently achieved a continuous artificial eclipse lasting nearly five hours. This groundbreaking feat allows researchers to regularly study the solar corona, a superheated region of the Sun that is usually hidden from view.[sciencenews+4]
Unlocking the Sun's Hidden Atmosphere
The Sun's corona is its outermost layer, a wispy atmosphere of plasma that extends millions of kilometers into space. It is much hotter than the Sun's surface, reaching temperatures between 1 million and 3 million degrees Celsius, compared to the surface's 5,500 degrees Celsius. Scientists call this the "coronal heating problem" and still do not fully understand why this temperature difference exists.[universetoday+5]
Normally, the corona is invisible from Earth because the Sun's bright surface completely overwhelms its faint light.Natural total solar eclipses, when the Moon perfectly blocks the Sun's disk, offer brief glimpses of the corona. However, these events are rare, occur in specific locations, and last only a few minutes. This limited viewing time makes it difficult for scientists to study the corona's dynamic behavior over longer periods.Furthermore, Earth's atmosphere scatters sunlight, interfering with ground-based observations even with specialized telescopes.[scied+8]
How Two Satellites Mimic the Moon
The Proba-3 mission overcomes these limitations by creating its own eclipses in space. It consists of two satellites: an "occulter" and a "coronagraph." The occulter satellite carries a 4.6-foot disk designed to block the Sun's light. The coronagraph satellite, equipped with the ASPIICS optical instrument, positions itself precisely within the occulter's shadow.[sciencenews+3]
These two spacecraft fly in an elliptical orbit around Earth, maintaining a constant distance of about 150 meters (492 feet) apart. They keep their positions with millimeter accuracy as they travel at high speed.This precise formation flying allows them to act as a single, enormous 150-meter-long coronagraph, effectively creating a "perfect" artificial eclipse.[sciencenews+8]
The mission successfully created its first artificial eclipse in March 2025.In September 2025, the Proba-3 mission achieved a continuous artificial eclipse that lasted almost five hours.This is a significant improvement over natural eclipses, which last only minutes. Proba-3 can maintain its artificial eclipse for up to six hours during each 19.6-hour orbit.[smithsonianmag+7]
Andrei Zhukov, a solar physicist at the Royal Observatory of Belgium and principal investigator for the ASPIICS instrument, expressed excitement about the early results. "We almost couldn't believe our eyes," Zhukov said. "This was the first try, and it worked. It was so incredible."He also noted that the artificial eclipse images are comparable to those from natural eclipses.[sciencenews+3]
First Views and Scientific Goals
The extended viewing time from Proba-3 allows scientists to capture detailed, time-lapse videos of the Sun's corona. During the five-hour eclipse in September 2025, the coronagraph took images every five minutes. This footage revealed previously unseen phenomena, including three massive plasma structures erupting and peeling away from the Sun.[scitechdaily+2]
Researchers can combine these images with data from NASA's Solar Dynamics Observatory, which observes the Sun's surface. This combination helps scientists understand how activity on the Sun's surface directly relates to events occurring in the corona.[scitechdaily+2]
A primary goal of the Proba-3 mission is to solve the coronal heating problem. Scientists also want to better understand coronal mass ejections (CMEs). These are huge eruptions of plasma from the Sun that can cause geomagnetic storms, disrupt satellites, and create power outages on Earth.Studying the corona with this new capability will provide crucial insights into these powerful solar events.[cbc+5]
Ground-Based Breakthroughs
While Proba-3 offers a space-based solution, scientists are also making progress in observing the corona from Earth. Researchers from the National Solar Observatory (NSO) and the New Jersey Institute of Technology developed a coronal adaptive optics (CAO) system for the 1.6-meter Goode Solar Telescope.[universetoday+1]
This advanced system uses computer-controlled, deformable mirrors that reshape themselves 2,200 times per second. This rapid adjustment counteracts image degradation caused by turbulent air in Earth's atmosphere, producing clearer images of the corona.Dirk Schmidt, an adaptive optics scientist at the NSO, led this research. Their work, published in Nature Astronomy on May 27, 2025, achieved a resolution of 63 kilometers for the corona.This ground-based technique allows scientists to see fine structures in the corona, offering another valuable tool for solar research.[universetoday+4]
Impact and Future
The ability to create prolonged, on-demand artificial eclipses marks a significant step forward in solar physics. Proba-3 has already observed at least 50 artificial eclipses since starting operations, with hundreds more expected in the coming years.[livescience]
These sustained observations will provide much richer and more accurate data than ever before. This data is critical for solving long-standing mysteries about the Sun, such as the coronal heating problem and the acceleration of solar wind. It will also improve predictions of space weather, helping to protect satellites and infrastructure on Earth.The Proba-3 mission is expected to gather approximately 1,000 hours of solar corona images over its two-year lifespan.[cbc+4]
