system
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human
[Avengers] How did Loki know to use Stark Tower as his power source base for the tesseract's portal creation? How could even set it up once he's there?

How did Loki know of Stark Tower in the first place? He's from another planet.  It's not all over the news, and even if it was, when does Loki have time to sit down and watch TV or read newspapers? Not too many people would've cared about Stark's new renovations of his building, which just so happened to promote the new renewable energy source.

Now I know the tesseract needed a power source to sustain the portal opening.  Maybe he had intel from the men he had working for him? But Hawkeye isn't in close contact with Stark, he was just a pawn, albeit a slightly higher level pawn, amongst the many SHIELD personnel. Loki also had Selvig and numerous SHIELD operatives, and with that I can throw in a few HYDRA people.  Now I can't see why any of these people would have any preference towards Stark Tower as a power source, as its just another building in down town New York (i think?), and unless you were full on up to date with the newest windmills, water turbines and renewable green energy sources, most high rise buildings in a densely populated region where unless you have a solo power source, energy will be shared amongst many, would not sit high in the priority list.  I'm not too sure but I'm sure things like the CERN Hadron Collider, or some nuclear fusion plant would have access to excuberant levels of power, and I'd go those places first....

But let's say one of them does enough research and finds out Stark Tower has the greatest new thing, some new self sustainable power source that some guy called Tony Stark derived for a whole building from a little smaller version in his chest built in a cave that can power entire arsenals of weaponry just in a human sized suit.  Once they're at the tower, rises the question of how they tapped into the energy source and just took it.  Jarvis said "Sir, I've shut down the Arc Reactor, but the device is already self-sustaining."  Which means, Jarvis has full control of the Arc Reactor, can shut it down, somehow didn't detect someone tapping into his source, and let someone build an inter-universe portal with it, OR it/he knew about it but didn't bother telling Stark straight away or shut it down straight away.  I'm not sure if this can be attributed to simply poor planning/security on Stark's behalf, and if not, how is this possible?
gpt
Loki didn't have to know.....Erik Selvig knew.  Once Loki had taken him over he would know that there needs to be a strong outside source of power to keep the portal open.  A power source that would of been talked about in PR releases when Stark Tower was taken off NYC's power grid and became a self sustaining building using Stark's new Arc Reactor.