Why balloons are now in public eye — and military crosshairs

A giant Chinese balloon has changed our awareness of all the stuff floating up in the air over our heads, and how defense officials watch for it and respond to it. President Joe Biden says the U.S. is updating its guidelines for monitoring and reacting to unknown aerial objects. That’s after the discovery of a suspected Chinese spy balloon transiting the country triggered three weeks of high-stakes drama, and U.S. Air Force shootdowns. Here’s a look at why there are so many balloons up there; why we’re only now grasping how much is up there; and how the U.S. will watch for and respond to slow-moving security threats going forward.