It’s an unlikely event, but it’s technically not impossible. Not everyone will receive it at the exact same moment, but it will eventually reach almost everyone on this planet. SMS is probably the most direct way to contact people. Forget e-mail, forget Twitter or Facebook, gosh, forget Television! Most people on Earth have a some mobile communication device and they have it usually all the time with them.
It’s an exercise. It’s fun. It is also powerful, maybe scary. But if you could send 1 SMS to everyone on Earth, what would it say?