I watch Spaceweather.com all the time for the near-earth fly-bys. And it seems that all of these particularly large <1LD flybys happen to pop up only on that day, or after.
What good is this system anyway ?! Are they just not telling us until they’re sure it’s a miss ?
I gotta believe they'd holler "duck" just so they would keep their reputations intact.
Asteroids, in the scale of celestial objects, are tiny, and scientists can only track them visually, since asteroids don’t produce any radiation we could detect.
They have to spot a tiny object visually, then spot it again and somehow confirm it is the same object before they can get an idea of its trajectory. Then they have to plug that into a computer and rely on inherently unreliable models to try and predict its future course. For really big asteroids this can be done pretty effectively, but those asteroids stay in the asteroid belt anyway.
Thats how much time the planet has. We spotted it on Saturday and Monday morning was splashdown. If its YUGE and mysteriously dark and undetectable we may only “know” about for a few hours and its really not gonna matter that much.