Where was Eleven going to find people

Question

Where was Eleven from Stranger Things going to track people (when she was going in the bathtub).

Was it the upside down?

If yes, wasn't she in danger as well?

If not then how did she even know so much about the upside down in the first place?

Answer 1

Where was Eleven from Stranger Things going to track people. Was it the upside down?

As we see in the course of the series, Eleven was being trained to use her psychic powers to spy on enemy commanders in far away places (on Earth.) The military organization operating out of the power plant had been using her to do this. I don't think she was fully present in the Upside-Down while projecting, but she was "pushing the envelope" between that dimension and our own. Her doing this is what drew the attention of the denizens of the Upside-Down and resulted in the portal forming in the power plant.

Incidentally, this process of "astral projection" (to borrow a more common term for this sort of thing) required her to be in a sensory deprivation tank. That's why she was using bathtubs and swimming pools when she did it to track Will Byers and the other girl - an "on-the-cheap" effort to replicate the deprivation tanks the military guys were putting her in.

If yes, wasn't she in danger as well?

Yes, she was. Not only in danger of being detected by the creatures of the Upside-Down, but also in danger because using these powers had a pronounced physical toll on her own body (hence the recurrent nose bleeds.)

However, I think she was less at risk of being spotted by the creatures in the Upside-Down while projecting, because she wasn't "fully" in that dimension. Her body didn't disappear from our world, it was just her mind going out and exploring. Unlike Will Byers, who actually went there through a portal (or was dragged through one by the creature) and was permanently, physically in that dimension.

If not then how did she even know so much about the upside down in the first place?

She only "knew" what she had seen while projecting for the military group that was using her in their experiments, which wasn't a lot, but still more than what she was able to communicate back to her watchers. It's also possible that she was somehow communicating with the creature while projecting - in some limited capacity - but that wasn't made explicitly clear.