[762X51]

Suppose anyone could be hiding anything from us?

Didn't NASA know that the tiles on the shuttle were damaged but chose not to tell the astronauts? I'd have to imagine that if NASA or any other governmental agency knew of an impending catastrophic strike they'd withhold that info since it wouldn't prevent said impact and would only cause panic among a doomed populace anyway. That's assuming a strike in or near North America.

[Strategerist]

NASA doesn’t control world astronomy.

[ProtectOurFreedom]

Rick Moran at American Thinker posits that the government wouldn't be able to keep it a secret because there are so many excellent amateur astronomers with powerful telescopes as well as privately-financed professional astronomers who are tracking NEO orbits:

Would government tell us if we were about to be hit by an asteroid?