As 70% of the earth's surface is water, the professor's team estimates that a plane thrown from the space station would have only a 4-5% chance of hitting land. That is why they would want an astronaut to release around 100 of the planes. The team hopes that in future they might be able to develop a tracking device that can be fixed to the plane. But in the meantime there is just a low-tech alternative - to write messages in various languages on the paper asking people to send it back to Japan if they find it. why don't they just aim for japan plus why do they want to chuck planes at the earth in the hope that they'll hit something solid that'll end in tears