Monday’s solar eclipse will give researchers another chance to study shadow bands, the thin wavy lines on the ground right before totality. They’re hoping to crack a 200 year old mystery.
SCOTT DETROW, HOST:
As millions of Americans look to the sky on Monday to witness the total solar eclipse, a group of University of Pittsburgh students will be chasing shadows in the Texas Hill Country. Sarah Boden with WESA in Pittsburgh reports that the young astronomers are on the verge of cracking the 200-year-old mystery of shadow bands.
SARAH BODEN, BYLINE: On a chilly afternoon in March, the Pitt students use duct tape and zip ties to close the opening of a weather balloon. The helium orb smells strongly of latex and is so large my arms would need to be more than twice as long in order to wrap around its circumference.
UNIDENTIFIED PERSON #1: Oh no, that is right. That was backwards.
BODEN: This is a practice launch for the actual experiment the students will be conducting to understand the phenomenon of shadow bands.
UNIDENTIFIED PERSON #2: There’s only one tape, but go the other side…
BODEN: Shadow bands are thin, wavy lines of alternating light and dark that seem to race across the ground right before and right after the moon completely blocks out the sun. No one knows why this happens.
MATHILDA NILSSON: One concept is that the shadow bands are caused by turbulence, like gravity waves in the atmosphere.
BODEN: Mathilda Nilsson is a junior studying astronomy and physics. Since German astronomer Hermann Goldschmidt first wrote about the phenomenon in 1820, two leading theories have emerged. One, as Nilsson explains – just before totality, only a sliver of sunlight is visible. As that sliver travels through the Earth’s atmosphere, it hits air pockets of different densities, and that causes refraction patterns to create the shadow bands. To test this, the students will send up their balloons equipped with weather…
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