I'm afraid we don't quite know what planet we're on, but it's definitely not Earth. [She can tell that much from what little she can feel of it. She's hoping her gamble with the name Earth helps - sure seems like most people here are from one anyway.] It's probably not any planet you've heard of, for that matter.
It's kind of both. I wouldn't expect to catch a flight back home soon.
[Hesitates for a moment then:]How familiar are you with the idea of parallel universes?