It has the same origins as the sky's blue hue
There's nothing quite like the beauty of champagne. Seeing fireworks shimmer through your New Year's Eve glass of bubbly is the stuff dreams are made of. But it turns out there's a ~secret~ element of beauty in every champagne bottle that you've probably missed whenever you pop it open. Initially reported by AFP, scientists at the University of Reims—which is in France's Champagne region—captured a stunning-but-short-lived "mini cloud" the color of the sky that escapes any bottle opened at the right temperature. The researchers used an ultra high-speed camera to capture the cloud and published their work in Scientific Reports earlier this week.
Though champagne arguably tastes the best when it's served cold, opening a bottle at just below room temperature—68 degrees Fahrenheit—will release the mesmerizing blue cloud. The cloud is colder than ice, only remains for only two or three thousandths of a second, and is absolutely fascinating.
You may have noticed the gray-white fog that released when opening a chilled bottle. This happens when the temperature of the gas rapidly plummets and condensates (called “adiabatic expansion”), but the blue cloud at 68 degrees was "totally unexpected," professor and study co-author Gerard Liger-Belair told AFP.
"Bottles at 20 C were under such a pressure (in the order of eight bar) that the adiabatic expansion allowed the temperature of the escaping gas to plummet to a glacial temperature of minus 90 C (minus 130 Fahrenheit)," Liger-Belair told AFP.
Those unbelievably cold temperatures are what cause the blue hue—and its similarity to the sky isn't a coincidence. "The bluish cloud forms when the CO2 transforms into miniature particles of dry ice which reflect the ambient light," Liger-Belair explained. "This blue cloud has the same physical origin as the blue color of the sky. Is that not extraordinary?"
Extraordinary indeed. Unfortunately, its fleeting nature means it's not visible to the naked eye, but you can try to capture it yourself with a high-speed camera, though it may take quite a few bottles of bubbly to test.
"It is simply a beautiful physics experiment done with a familiar product," Liger-Belair told AFP. "Who would have thought that in a few milliseconds, we would find such extreme conditions during the opening of a bottle of champagne?"