Originally Posted by Moogs
My official guess: all the Hollywood scenarios would never happen. If officials really feared a big-time impact, and they thought it was species-threatening, they wouldn't tell us IMO unless they had a great plan in place for deflecting it. IOW, the one that kills us, we'll never see coming (from our perspective). Governments will decide not to cause a panic / mass hysteria, try to squirrel away some important people and human knowledge in a cave somewhere and hope for the best. Deep Impact / Armageddon scenarios will never happen.
It wouldn't happen but not for the reasons you state. I for one think that most scientists are way too earnest people to hide something like that. I mean, they're not FBI agents.
But what I'm getting at is that it's really hard to accurately predict the path of one of these objects. If one is going to hit the earth, we probably wouldn't even know it until it's practically on top of us. Even then, there's always the chance of a near-miss scenario where it skims our atmosphere without actually hitting. It's not like the all-seeing government would know that we're destined for an impact in several months' time and would purposely hold back information. They might know that a particular object is going to have a close approach, but that's about the best they can do.
On top of that, there are thousands of amateur astronomers who look at the sky each night and would probably eventually figure out that there was an asteroid heading for earth.