re: It is interesting that Hermes has come so close to Earth so many times without being seen by anyone.
What is more interesting is that there are two objects orbiting each other, I wonder if at one time it was only one rock that split up, but if so, then why have they stayed together.
On the SF thoughts about it; perhaps they are alien equivalent to our cruse ships and some of the other world inhabitants take a short tour of our inner solar system every now and then. ;-)
Cheers
Johannes