Popping Champagne Creates A Tiny Supersonic Shock Wave

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  A group of scientists decided to study the pop of a champagne bottle recently, because they could. And what they discovered was that the shock waves coming out of a bottle of bubbly is similar to the supersonic exhaust of a fighter jet. Wow. But how did they figure this out?

  To begin, the scientists bought 6 champagne bottles and stored two at 86 degrees Fahrenheit, two others at 68 Fahrenheit. All four of these bottles had been aged for 42 months in what is called a prise de mousse - a type of alcohol fermentation that gives champagne it's bubbles. 

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  The researchers then used a high speed camera to take a succession of photos as the bottles were uncorked. They found that when the cork popped out of the bottle, it was violently pushed by rapidly expanding carbon dioxide and water vapor that had been restricted in the neck of the bottle. The sudden change in temperature caused the carbon dioxide and water vapor to cool down quickly, changing them into ice crystals which then condensed into a fog that can be seen in the photos, wafting out after the cork. 

  However, within the first millisecond of the cork popping, the sudden drop of pressure inside the bottle led to shock waves called Mach disks. Mach disks also occur in the exhaust of fighter jets, and are formed because the escaping gas expands into the air very quickly, at over twice the speed of sound. This process stops as quickly as it begins. 

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  The formation of the Mach disks was surprising for the scientists, as they were aware of Mach disks in aerospace engineering, but not in champagne bottles. The bottles at room temperature also created a different pop than those stored in cooler temperatures. This is because carbon dioxide is less soluble at higher temperatures, meaning that bottles stored at cooler temperatures will have louder and more forceful pops. 

  So next time you pop open a bottle of champagne, appreciate the drink for what it is: not only a delicious alcoholic beverage, but also a tiny supersonic shock wave. 

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