When the aircraft is flying at a height of 10,000 meters, the temperature outside the cabin is minus 50 ° C, and when it reaches a temperature of 20,000 meters, the temperature is even lower. Everest at an elevation of 8,844 meters is only 34% of the sea level, and air pressure at 20,000 meters is lower.
Two Christmas years ago, a group of British people suddenly wanted to use "lantern strings" to light up space.
The test of romance is the manufacture of the product. A common human "lantern" play cool, cold, low pressure of 20,000 meters altitude? Craft and design can withstand those extreme environments?