The Great American Eclipse Left 'Bow Waves' in Earth's Atmosphere

Wednesday, 27 December 2017 - 12:09PM
Earth
Moon
Wednesday, 27 December 2017 - 12:09PM
The Great American Eclipse Left 'Bow Waves' in Earth's Atmosphere
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Image Credit: Seanriddle via Wikimedia Commons.

Just about everybody and their grandma spent August 21st, 2017 looking up at the sky wearing a pair of cheap paper glasses, trying to see the Great American Eclipse, but few people realized that they were witnessing a landmark moment in scientific history. Scientists have theorized for years that eclipses cause a disturbance in the atmosphere, but no one had ever been able to measure it...until 2017.

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Thanks to the work of MIT's Haystack Observatory and the University of Tromsø (located in Norway), along with roughly 2,000 receivers spread across North America, scientists have proven the existence of 'bow waves' in Earth's atmosphere following an eclipse. Here's how the new research paper, published in Geophysical Research Letters, describes the phenomenon:

Opening quote
"During solar eclipses, the Moon's shadow causes a large reduction in atmospheric energy input, including not only the stratosphere but also the thermosphere and ionosphere. The eclipse shadow has a supersonic motion which is theoretically expected to generate atmospheric bow waves, similar to a fast-moving river boat, with waves starting in the lower atmosphere and propagating into the ionosphere."
Closing quote


Eclipses happen every year (or year and a half), but the August 21st eclipse was the first time an eclipse had crossed the breadth of the United States in 99 years, and the first total eclipse in the US since 1979. In addition to bow waves, scientists across the country took the opportunity to do some investigation into the sun's corona, including looking into the behavior of solar flares.

If you want a quick reminder of just how freaky the eclipse was (both here on Earth and in space), check out this video from the New York Times:



In case you missed it, you won't have to wait 30 years for the next one—the next total eclipse over the US will be on April 8th, 2024.

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Scientists Prove The Existence of 'Bow Waves' After Eclipse
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