I know it’s not real by any stretch of the imagination, but isn’t there a far more reasonable explanation than aliens in this short bit of Doctor Who? (It starts at 4:20 of this clip. Transcribed below because I don’t know how long the video will be up.)
The Doctor: “Now that’s interesting”
The Doctor: “Scanning for life forms. If I do a scan looking for your basic humanoids – you know, your book readers, few limbs and a face – apart from us, I get nothing. Zippo. Nada. See? Nobody home. But if I widen the parameters to any kind of life …. [taps on keyboard]…. a million-million [something] after that. A million-million….”
Donna: “But there’s nothing here. There’s no-one.”
The Doctor: “And not a sound. A million-million life forms…and silence in the library.”
Donna: “But there’s no-one here.”
Uh… yeah…. I’m not sure about The Doctor, because he’s not really human, but Donna is covered in bacteria. That’s more than 1012 (a “million-million”) non-humanoid life forms in Donna alone.
And that’s what I think when I watch a scary episode of Doctor Who. I totally accept libraries that exist in the future in a little girl’s head, but find their lack of bacteria unrealistic.