I'm seeing estimates that on the order of 21 million party balloons are sold and possibly released each day globally. Around 5 million each day in the U.S. The flight time depends on many factors, but flight time can range from an hour to weeks.
With flight times measured in hours to weeks, there is a reasonable chance that there's one in the sky near you now. Assuming just the continental U.S. it works out that if each balloon is airborne for exactly 24 hours, there are 1.6 balloons per square mile assuming even distribution (which it isn't), Depending on how good your vision is, and how big the party balloon is, and how far away it is, and restricting your view to anything greater than 30 degrees above the horizon there would be perhaps 14 or so in your field of view of the sky at any given moment, however, most would be invisible without magnification, and they are not evenly distributed in the sky.
Essentially, if you go looking for a object flying in the sky, that doesn't look like an airplane, you will almost certainly find one or many.
Just throwing this out there for those he think that balloons are an over-rated explanation.
With flight times measured in hours to weeks, there is a reasonable chance that there's one in the sky near you now. Assuming just the continental U.S. it works out that if each balloon is airborne for exactly 24 hours, there are 1.6 balloons per square mile assuming even distribution (which it isn't), Depending on how good your vision is, and how big the party balloon is, and how far away it is, and restricting your view to anything greater than 30 degrees above the horizon there would be perhaps 14 or so in your field of view of the sky at any given moment, however, most would be invisible without magnification, and they are not evenly distributed in the sky.
Essentially, if you go looking for a object flying in the sky, that doesn't look like an airplane, you will almost certainly find one or many.
Just throwing this out there for those he think that balloons are an over-rated explanation.
