Does these strings have mass? So, everything's made of these strings. Obviously, dark matter would also be made of strings, vibrating to give them certain properties? What makes them vibrate? Are photons made of strings? If strings have mass, then the mass can't just vanish, if photons are strings.. Could strings vibrate a certain way to be energy? I kow there's a connection between energy and mass, but does energy have mass? I know, lousy questions. It's just that I'm wondering.