CATHERINE AURA

Judging from the other posts, it appears that it is visible to us. But "us" may not be the human world you're thinking about. Most likely we're a different one, and your human world is completely oblivious. Since your Nigel and Ms. Aura ended up as dolphins in your human world, the Ms. Aura with a twitter account may not be the same one, either. Or it might. Or it could be a human fan having fun. We do strange things for fun. Ask anyone who goes to a SF con.

Let's really break out the SF here. In theory there can be different forms of multiple universes. A common one in SF is good ol' alternate reality, whether it stems from tinkering with time lines or simply scooting over to the universe where you decided to have eggs and bacon on Monday instead of a bowl of cold cereal. I think this is what's known as a Level III universe.

On a more, "mundane" level is that it's possible for similar worlds to exist within the same infinite space. An identical "Subject L" could be sitting as close as 10^118 meters away. While not a parallel universe as typically shown in SF, it would nonetheless allow for multiple earths. This is known as a Level I Universe. A little dark matter here; a pinch of handwavium there, and you have a wormhole connecting two similar earths. And if the wormhole is always open, then it should be possible to have some "leakage," if both have some form of wireless communication.

In either way, given infinite space, even in a Level I universe there should be a possibility of a huge "Cosmic Coincidence." Planet A has a connection to Planet B, but on Planet Z, both A and B are a work of fiction. Thus what is strictly entertainment on Z is history of A and B.

I'm surprised that our "Subject C," from an advanced society with time travel, wouldn't pick up on this.

The kicker is that if A and B become aware of Z, there's no guarantee that the fiction on Z will always mirror A and B. Then again, it could. Infinities are fun.

Or perhaps (with a nod to the late Michael Crichton and Timeline), the people of "Subject C" do not achieve true time travel, but wind up in an alternate Level III universe to play with. Or maybe they "simply" wind up on a Level I world that looks like it's pre-human and they conspire to make it so.

Here's something for "Subject C's" traffic analysis to chew on: Suppose that her class Aves did not achieve sapience through evolution but through genetic engineering of her world's departing humans. Class Aves of her world may be the only ones to "make it," as it were, but it would explain sapience across the entire class. And if all this is takes place in a Level I universe, then those original humans could still be out there, on their adopted worlds, in a similar form - or perhaps one so advanced we'd no longer recognize them as human. In which case they could be pulling the strings on "Subject C's" class just as "Subject C," in turn, pulled the strings on "Subject L's" world - and "Subject C" may be none the wiser.

Isn't SF fun?