The American expedition will want to affect the political situation to favor themselves and their allies, the Chinese will do likewise for themselves. Aside from the spaceships, the technology they have is not so different from what we have today, this is only seven years in the future after all. You think the Chinese will try to land an expedition in Kara Tur?
Ooh! Maztica has some . . . issues as a created setting (just once I would like to see a Mesoamerican setting in an RPG that doesn't assume they must be evil, because human sacrifice, without bothering to understand what nextlaoaliztli actually
meant, but I digress), but I can only imagine how Mexico and the Chicanx movement in the US might react to extant Nahua-like and Maya-like cultures being found ~ with magic, no less!
The Earthers will just assume they are dealing with a bunch of primitives that they can impress with their advanced technology.
I love the image that summons up in my brain ~ Earthers swaggering into a situation being all like "Look at my fancy iPhone" and "This is my boomstick" and "Oooooh, look ~ LIGHTERS", and Torillings being all like, "Booooooring. When do we get to talk to this Yahweh person you keep yabbering on about? Seriously, did you like piss him off or something? Cuz our gods answer our questions."
Speaking of religion, how might it be affected by Terra-Toril interactions? Heathenry, Finnish polytheism, Kemeticism, and my beloved Sumerian devotion (I'm a worshiper of Ninshubur) would prolly all get a boost up, considering qweens like Tyr, Mielikki, Loviatar, the Mulhorandi pantheon, and the Untherese pantheon all have active cultures worshiping them and numerous priests, priestesses, and priestixes that can literally call them up and say, "Hey, qween! Spill the tea!"
But what of Islam? How would it interface with the Law of the Loregiver and the Enlightened Gods (the Torilese "equivalent" ~ it's not really equivalent).
Elminster has been known to travel to non-magical planes, so he might be able to teleport himself to Earth and back, the level of magic is lower but not nonexistent. Elminster is one of Mystra's chosen, so he is able to bring his magic with him, as are others of his kind. His ability to scry is limited to areas where magic is prevalent, He can teleport to Earth, but he can't scry there. If he is there, he can scry to see what is happening on Toril, because that place already has magic in it. Likewise the gods of Toril can also transport themselves to Earth if they want to go there, the act weakens them however, so it is not a place they would actually like to go unless they have no other choice. There are other depowered deities on Earth that are living a quite existence, they keep a low profile however. Magic was once more prevalent on Earth than it is now.
Come to think of it, it's at least demi-canon that Elminster has, in fact, been here before. And as I recall, that's popped in a number of places at a number of different levels of canonicity.
And we've gone there before, too ~ the Mulhorandi and Untherese are literally Egyptians and Sumerians kidnapped into slavery by the Imaskari.
If a piece of their universe has been inserted into ours, how is it possible that it is effecting gravitational perturbation in the same way? How is an orbital insertion possible into space where different physics apply?
You can’t have your cake and eat it.
Sure you can ~ you might have indigestion, though. In fact, the roughest part of sending a ship into Torilspace would likely be navigating that border at 800,000 km. It'll be like when a plane crosses from a cold front into a hot front, only instead of rain and wind, it'll be the laws of physics raggedly throwing the ship around. Who's to say what the knock-on effects down the causal chain will be of that kind of chaos? Different gravitational constants interacting might very well end up pulling orbits in weird ways.
Which I guess you might have considered, since you said "in the same way" in your post >.< D'oh!