我刚在雅虎上看了一篇文章，转录几段：
The United States is going to need a lot of missiles if its fighter jets are to shoot down every stray balloon that sets off a radar warning in American airspace.
、、、At any given moment, thousands of balloons” are above the Earth、、、Each year, around 60,000 high-flying balloons are launched just by the National Weather Service, the agency said. They rise into the stratosphere,、、、Then there is NASA, which runs a program from Palestine, Texas, that over the years has lofted more than 1,700 large balloons on scientific missions that can last for months. The balloons fly up to 22 miles high, and the payloads weigh up to 4 tons, 、、、
