As a professional in his field Dr. Jackson is recruited to decode the massive mechanism that had been unearthed at the Giza Plateau forty years earlier. In all that time (who knows when they actually started working on it), the scientists hadn't been able to get it to do more then whirr and vibrate impressively - surely it did more.
I would be curious to know how they arrived at the point of the beginning of the movie. How did they get the bright idea that the thing was a machine that needed power to operate? In the first movie, there was no dialing mechanism like the subsequent movies and shows had (you see they saw that little problem too). You have this machine that does something, but how do you tell it to do whatever it does? Also, or maybe firstly, how did they jump to the conclusion that it did anything at all. There is the outer ring, and the inner ring, and they move causing symbols to line up, but to what point? When did they discover the little arrow markers moved too? and how would they know that it did anything more? Yeah, that would be an interesting movie - or maybe a very boring one - who knows?
But I digress - I do that frequently.
Back to my point. Dr. Jackson had an apparently unique view on translating the hieroglyphics and symbols on the rings, which was of course the breaking point of the whole project. Because of that, he immediately stepped into the position of head translator of the entire project. Who knows what happened to the other guy; he just kinda went away.
So they draft a military team and blast off to the other side of the universe to see what they can find, all on the assumption that the good Dr. Jackson can get them all back simply by twiddling with the ring they saw at that end. But, it wouldn't be a movie if it was so easy, and boy are members of the team totally pissed off when they find out that he can't just spin those rings and get them back home.
The whole point of this is, what can Daniel know, and what must he learn? He knows the written language, something that was forbidden the residents of this world centuries ago, but he has to learn how to speak it so he can talk with them. This apparently takes moments, but we're talking about a movie here so allowances have to be taken. Then again, maybe he can already speak modern Egyptian; it would certainly be logical considering his expertise, but that doesn't seem to be the case. Maybe I should see if I can find this book and see what it says there; things are always so different in books. I always did find it rather odd that someone went to all the trouble to cover the walls of that cave with their last history without including the symbol that represented their home planet. That had to be found in the doodlings of a child, regardless of the fact that he was the son of the headman, and possibly the best educated among them, considering they weren't allowed to make symbols of any kind anywhere.
So what can a character know? The boy probably wouldn't even think to sit down and start drawing in the sand. Daniel had no reason to suspect that the pyramid drawn by that boy was the representation of Earth. But it's a movie and it worked. At least those who weren't killed got to go home, those that wanted to.
So I'm just saying, be careful with what your characters can know, and what they can find out. Even the top hacker on the planet can only learn so much about one person. Without some kind of a face-to-face interaction, that person can still be unpredictable; there still might be something, accidentally or intentionally, kept personal and secret.