We're mostly safe because there's nothing really close and big enough to cause us trouble. There's always the outside chance of a direct hit from a GRB making things a little toasty but otherwise our biggest near-term threat is likely to come from an asteroid.
The fact is, it's kinda irrelevant. If some major issue were to come from space, we'd be pretty much doomed.
Reminds me of a scare story from the Global Warming Panic Merchants a few years ago, claiming that the dawn and dusk times on the Arctic circle had shifted by an hour due to global warming. When it was pointed that that that is impossible, they back tracked and claimed it has been a statistical glitch.
If conclusive evidence that the world will end, for a certainty, at x or y time. One thing and only one is for certain, we will never be told about it.