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QuoteUntil recently, the dazzling visual effect caused by helicopter blades hitting sand and dust - and creating mesmerizing halos described as 'one of the most beautiful things you'll ever see in a war zone - had no specific name; observers would simply marvel at the breathtaking sight without an understanding of what was causing it - or what to call it.
Now, however - to honor the memories of two soldiers killed in the war in Afghanistan - the physics that create these types of breathtaking halos has a name: The Kopp-Etchells Effect.
The effect is named for U.S. Army Ranger Benjamin Kopp and British soldier Joseph Etchells, and was given its title by a photojournalist Michael Yon - who was covering the war and captured the effect in dozens of photos - as a way to honor the fallen soldiers.
Source: http://www.michaelyon-online.com/mesmerizing-halo-effect-caused-by-blades-of-landing-combat-helicopters-named-in-honor-of-two-fallen-soldiers.htm