As the eclipse darkens the sky over Greenland, Iceland and Spain, millions will look up to see its distinctive ring of fire. Scientists will be looking especially intently, hoping to learn more about the sun and its unique relationship with our planet.
Before the eclipse had even begun, scientists were making predictions about the shape that the sun’s outer atmosphere, the corona, would take. The sun’s unpredictable magnetic field, which determines this shape, is also the force that drives solar wind, solar flares and coronal mass ejections, all of which send material from the sun out into the solar system.
Matching predictions about the sun’s corona to direct observations during an eclipse can help scientists check their understanding of the sun’s magnetic field and refine their forecasts of the space weather it can cause.
During the eclipse, scientists at NASA will fly jets equipped with special cameras to capture views of the corona. They will also send weather balloons into the path of totality — the area in which the moon completely blocks the sun — to understand how the eclipse’s sudden darkness affects our atmosphere.
“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,” Kelly Korreck, the eclipse program manager at NASA Headquarters in Washington, said in a statement.
Teams in Iceland are releasing 80 of the agency’s weather balloons before, during and after the eclipse to create a timeline of its effects on the size of Earth’s “boundary layer,” the lowest part of the atmosphere. Three teams in Spain are also releasing balloons equipped with 360-degree cameras and sensors to see how darkness affects ozone production.
Citizen scientists will also have the chance to get involved with eclipse work, submitting videos to researchers of their experience viewing phenomena like daytime light pollution — excess artificial light outdoors — and eclipse shadow bands, the rippling patterns of shadow that move across the ground just before and after totality.
Citizen scientists in Spain are also taking upcoming eclipses as opportunities to study animal behavior. When the sky darkens, many species act differently, finding safe places to hunker down, starting to fall asleep or even becoming agitated. Over the next 18 months, as two more eclipses pass over Spain, more than 200 citizen scientists will record these behavioral changes as part of the filmmaker Ángel García-Rojo’s TriEclipse Project.
“For me, perhaps the most exciting part is actually the people taking part and the sense that all of us can contribute to something beautiful together,” Mr. García-Rojo said. “More than 200 people are essentially going outside together, watching carefully and asking the same simple question: What will the animals do when the daylight suddenly disappears?”