Nadai, you stole my response. I was going to say control as well, but also credibility. Not only do they want to control us, but also, as part of that control, they would want to hide certain extraterrestrial facts that could, if they made them public, cause a lack of belief or faith in them because it would sound so insane (true or not).
Imagine what would happen to our world if we found solid proof that aliens existed!
*Myrddin maybe you can help me with a title*
I read a novel a few years ago where aliens came to Earth. Of course everyone was terrified and curious about their intentions. The aliens refused to come out of their space ships-I think for eighty years-because they wanted plenty of time for people to get used to the idea of aliens on Earth and to forget any prejudices that they might have felt when aliens first arrived, or something like that. They had a human spokesman who relayed messages to the people, including that eighty-years rule. I think he died before the big reveal though. Eventually, humans started focusing less on war and more on the aliens and so fighting stopped and I think all the countries unified and became one united state. I don't remember what happened later on in the novel, like I said it was a while ago, but it was a pretty interesting book. I wouldn't mind reading it again.
But I wonder what would happen to our world if aliens were to all of a sudden drop from the sky. Would the same thing happen to us? And where would religion be? Would the Pope and other religious leaders just work aliens into the Bible and other texts, "oh yeah, we missed that part, but here it is, 'and aliens will come down from the heavens!'" Or will they try to say that aliens aren't real, like some do with dinosaurs? I've learned about a few ancient civilizations who believed and spoke of "sky people" who taught them how to build and speak and such, but what about our modern religions? Maybe that's another reason the government holds on so tightly to their keys to Area 51. I'd hope, though, that if aliens did decide to make an appearance, that they wouldn't wait eighty years to show themselves.