The August Eclipse Left A 'Wake' in the Earth's Upper Atmosphere
Source: Gizmodo
The August Eclipse Left A 'Wake' in the Earth's Upper Atmosphere
Ryan F. Mandelbaum
Yesterday 12:00pm • Filed to: TOTAL SOLAR ECLIPSE 2017
A total solar eclipse by itself isn’t so unusual—the moon shades the Sun every 18 months, from the view of somewhere on Earth. But this year’s “Great American Eclipse” was special simply for how much inhabited land it covered, crossing the length of America from Oregon to South Carolina. And that led to some amazing new scientific observations.
Researchers at MIT’s Haystack Observatory and the University of Tromsø in Norway observed the eclipse’s strange effects on atmosphere using 2,000 sensors receiving positioning satellite data. They were able to confirm a theorized behavior so small that it hadn’t been detected before: atmospheric “bow waves,” like the outermost waves of a ship’s wake. These waves tell an important story about the complexity of Earth’s atmosphere.
“We were looking at some phenomena that were expected but never had the chance to be observed,” study author Shun-Rong Zhang from the MIT Haystack Observatory told Gizmodo. “That was the surprise we found... we had a large coverage and our system is sensitive enough to be able to see these smaller variations. That was really very interesting to us.”
The Sun’s heat provides energy to Earth’s atmosphere. The Moon passing in front of it causes a noticeable decrease in the energy in the shadowed zone. The shadow travels fast enough that it should create a bow wave in the atmosphere—the same idea as the trailing v-shaped waves left behind by boats traveling in water. The eclipse’s bow wave was too slight to detect—until now.
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Read more: https://gizmodo.com/the-august-eclipse-left-a-wake-in-the-earths-upper-atmo-1821503369
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Related: Ionospheric Bow Waves and Perturbations Induced by the 21 August 2017 Solar Eclipse (Geophysical Research Letters)
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