Solar expert in Dayton: 'Like the sun is setting in every direction all at once'
Apr. 8—Today's total eclipse will plunge the Dayton region and a large swath of the United States into darkness for a couple of minutes during daytime hours.
When eclipse totality starts, it will seem like the sun is setting in every direction all at once, said Justin Kasper, chief of technology at BWX Technologies and a professor of space science at the University of Michigan.
"You will see that night kind of appears above you and descends down to the horizon in every direction," he said.
But another novel part of today's event is that when the moon blocks the light from the sun, observers should be able to see the weak bit of sunlight that reflects off of the sun's extended atmosphere, which is called the corona, Kasper said.
Total solar eclipse in Ohio
Ohio today is seeing a total solar eclipse for the first time since 1809. Our complete coverage: — —LIVE UPDATES: What our reporters are seeing throughout the region — —EVENTS: What's happening today in southwest Ohio — —TIMING: What time is the eclipse? — —LENGTH: How long will the eclipse last? — —VISITORS: How businesses are trying to cash in — —PHOTOS: How to photograph the eclipse — —HISTORY: What happened in the total solar eclipse of 1806? — —SIGN UP: Get the news of the day delivered to your inbox every morning with our free Morning Briefing newsletter. — —SUBSCRIBE: Like what you see? Explore all special offers here
The corona is the outermost part of the sun's atmosphere, which is usually hidden by the bright light of the sun's surface, says NASA. The eclipse should provide a rare glimpse of the atmosphere.
About an hour before the eclipse, the moon will start passing in front of the sun, said Kasper, who has worked on NASA missions that study the sun in space.
If viewers are lucky, they might be able to see dots on the surface of the sun, which are sunspots that are bigger than Earth, Kasper said.
Kasper, who lives in Washington, D.C., is the brother of Hannah Kasper Levinson, who is an art educator in Dayton. He is in town to watch the eclipse.
When the moon is centered over the sun, observers sometimes can see beads of light, which is sunlight shining through mountains on the surface of the moon, he said.
Kasper said it's possible viewers will get to see hot material in the solar corona from solar flares "peeking" around the moon.
The sun's corona is unstable, and this instability can lead to solar flares and space weather that can damage satellites, injure astronauts and disrupt life on Earth, Kasper said.
The sun's atmosphere is far hotter than the sun itself, he said, noting that space weather causes billions of dollars of damage on Earth every year.
Kasper was one of the principal investigators with the Parker Solar Probe, which is the first spacecraft to fly through the sun's upper atmosphere. He said the spacecraft dips into the corona roughly every three months.
The probe emerged from the corona a few days ago, after taking a variety of measurements.
Scientists will be able to compare detailed photographs of today's eclipse with information gathered by the probe. Scientists hope that studying the sun's atmosphere will help them find ways to predict space weather.
Kasper said he has witnessed partial eclipses on multiple occasions, but this will be the first time he gets to see a total eclipse with his own eyes.
Kasper watched the 2017 eclipse in Ann Arbor, Michigan. Even though Michigan was not in the path of totality, Kasper said it was still a very special experience.
Kasper said he hopes the eclipse is a fun, unifying experience for the community.
