- This is the first total solar eclipse visible from mainland Europe since 1999
- Nearly 1 billion people could see at least part of the eclipse, while about 15 million live within its narrow path of totality
- Scientists will use the fleeting darkness to study the Sun's corona and atmospheric changes
A total solar eclipse will pass over parts of the Northern Hemisphere on Wednesday, briefly turning day into night along a narrow path from the Arctic through Iceland and into northern Spain.
The Moon will pass directly between Earth and the Sun, completely blocking the Sun’s bright face for observers inside the path of totality.
Outside that band, a partial eclipse will be visible across much of Europe, northwestern Africa and portions of North America.
When and where?
The greatest eclipse will occur at about 17:46 UTC, with maximum totality lasting 2 minutes and 18 seconds near 65 degrees north latitude in the North Atlantic, west of Iceland, according to NASA.
The path of totality, roughly 294 kilometers (183 miles) wide at its broadest, crosses remote areas of northern Russia and the Arctic, eastern Greenland, western and northern Iceland, the Atlantic Ocean, northern Spain and a sliver of northeastern Portugal.
Cities expected to experience totality include Reykjavik, Leon, Zaragoza, Bilbao, Valencia and parts of the Balearic Islands. In Spain, the event occurs low on the western horizon shortly before sunset.
Nearly 1 billion people are in areas where at least part of the eclipse could be visible, including about 15 million living within the narrow path of totality.
Coverage reaches more than 90% across much of western Europe and approaches 99% near Madrid and Barcelona, which lie just outside the total path. Partial views also extend to parts of Alaska, northern and eastern Canada, and the northeastern US.
This is the first total solar eclipse visible from mainland Europe since 1999 and the first over the Iberian Peninsula in more than a century. It is the only total eclipse Iceland will experience this century.
Anyone outside the path of totality — including in Türkiye — will not see the eclipse.
Why it matters
Total eclipses briefly expose the Sun's outer atmosphere, or corona, which is normally invisible against the Sun's glare.
Scientists use the rare alignment to study solar activity that shapes space weather on Earth.
NASA-funded teams plan to track the Moon's shadow using a high-altitude research jet and scientific balloons launched from Iceland to study how the sudden darkness affects the atmosphere.
"From our unique perspective on Earth during a total solar eclipse, scientists can study the Sun’s corona in a way we can’t from anywhere else in the solar system," Kelly Korreck, eclipse program manager at NASA headquarters, said in a statement last month.
"The Sun impacts our daily life, satellites, and astronauts in space, and we can take advantage of this moment to advance our understanding of that influence.”
Amir Caspi, a researcher involved in NASA's eclipse studies, said each eclipse offers new data. "The Sun is always changing," Caspi said. "Every eclipse is different. So we could see things we didn't see before."
How to watch safely
Experts stress that it is never safe to look directly at the Sun without certified eclipse glasses, except during the brief seconds of full totality.
Regular sunglasses do not offer adequate protection.
NASA recommends eclipse glasses that meet the ISO 12312-2 international safety standard, or an indirect method such as a pinhole projector.
Cameras, telescopes and binoculars require their own solar filters to avoid eye and equipment damage.
On the ground
Iceland has leaned into the rare event. In Hellissandur, on the Snaefellsnes Peninsula, organizers are hosting the Iceland Eclipse festival, from Aug. 11-15 with live music and talks from scientists and astronauts timed around totality.
Cruise operators have also scheduled voyages timed to the eclipse along the Iceland-Spain corridor, and tourism authorities in both countries have published viewing guides as hotels and rental cars near the path have filled up in recent months.
The eclipse also falls during the annual Perseid meteor shower, which peaks around Aug. 12-13, giving skywatchers a second celestial event that night.
NASA said it would stream the eclipse live starting at 1:15 p.m. EDT (1715GMT) on Wednesday.
The next total solar eclipse will occur on Aug. 2, 2027, crossing Spain, the Middle East and parts of North Africa.
