The sky will go dark. The temperature will drop. Stars will shine in the middle of the day. For the first time in nearly a century, millions of Americans from coast-to-coast will witness a total solar eclipse. Those who have watched the sun suddenly snuff out say it’s an otherworldly feeling. It can be humbling. It can be spiritual. It can change the course of history SN: 5/13/17, p. 29).
But as the moon passes in front of the sun during the Aug. 21 Great American Eclipse, scientists will be doing some serious work.
“Everybody’s taken in by the beautiful dark sky,” says Padma Yanamandra-Fisher of the Space Science Institute’s branch in Rancho Cucamonga, Calif., who will observe the eclipse from Carbondale, Ill. “But that part is so dominant that people don’t always appreciate the nuances of the science you can actually do.”
Many of the scientific questions researchers are after have to do with a big doughnut of space around the sun observable only during a total eclipse. This doughnut, the inner corona, is the part of the sun’s tenuous atmosphere that starts right at the sun’s surface and extends out to about 2½ solar radii. It happens to be where a lot of the most interesting solar physics happens.