Is there any other way to send signals a significant distance other than with EM radiation or (doubtfully) gravity? By signal I mean the complex information that we are able to send via radio or other EM transmission. I don't think there is any other way other than EM radiation but I cannot think of an air tight explaination why this is the case. There are no other forces available for such a signaling method. The Strong and Weak forces are too short range and gravity is a monopole force and extremely weak which makes it difficult to use for a signaling method. Can anybody either shoot down my claim or find a better explaination why EM radiation is the only possible way to send signals.