[Voice] *goes with Ketsu's convention of calling it Earth too*
[Dude, you have a gateway to another Earth in you!]
If it wasn't, then we wouldn't be here, now, would we?
We're not exactly on Earth anymore. The technology is way more advanced here. We barely have computational engines back home, and here's an underwater prison with a computer prison warden that can think for itself.
Just ask Fletcher when you find him. He'll tell you it too.