A partial solar eclipse will come to Earth on Saturday, March 29, 2025, as the moon passes in front of the sun. From Earth, photographers will capture images of a bite being taken out of the sun. From space, a fleet of satellites will image a shadow being cast across Earth.
The moon projects two kinds of shadows at all times. There's a large fuzzy outer shadow, called the penumbra, and a much smaller, darker central shadow, the umbra. The latter causes a total solar eclipse, which is seen across a dark and narrow corridor on Earth called the path of totality. That's not what's happening on March 29, when only the moon's penumbra will touch Earth.
Related: Where will the partial solar eclipse be visible in March 2025?
What will satellites see during the eclipse?
Although a partial eclipse will be seen from Europe, western Africa, eastern Canada and the northeastern U.S., satellites will see a dark shadow across the Atlantic Ocean that will blend with the night side of Earth. Why? It's down to where the moon's penumbral shadow will be darkest. This partial solar eclipse is so very early as a total solar eclipse. At its maximum point in the Nunavik region of Quebec, Canada, observers will see 94% of the sun blocked by the moon at sunrise. This is where the eclipse shadow will be at its darkest. As the penumbra spreads across Europe, where only a relatively slight eclipse will be seen, the moon's shadow will be much lighter and thus harder for satellites to show.
Why the moon's shadow will move from west to east
The shadow of a solar eclipse always moves from west to east even though the sun, the moon and stars appear to rise in the east and set in the west. That's because the moon orbits in the same direction as Earth's rotation, but at 2,300 miles per hour (3,700 kilometers per hour), it travels twice as fast, according to Ernie Wright at NASA's Scientific Visualization Studio. Earth's curvature further increases the speed of the shadow.
Where to see satellite images of the moon's shadow
Geostationary weather and environmental monitoring satellites orbiting 22,000 miles (36,000 kilometers) from Earth tend to capture the best images of an eclipse shadow. Satellites to look out for, which in the past have imaged solar eclipses, including GOES-16, Copernicus Sentinel-3 and Himawari. It's also possible that astronauts aboard the International Space Station will image the eclipse, as they did during the total solar eclipse on April 8, 2024. For that, follow astrophotographer-astronaut Don Petit, who's currently on the ISS and sending back spectacular imagery.
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