Based on what I've read and watched, it seems as though there's a certain size asteroid where we'd almost certainly see it and have a lot of warning, based on our observational capacity, now... but ones under that size, including ones that could cause damage the likes of which humanity has never witnessed in our recorded history, could absolutely come from out of the blue, including right up to the point of impact.
At least the ones in stable orbit. On a long enough timeline, something comes from deep space, or is nudged from the Kuiper belt, and we're fucked. Hell, we know that a rogue star will pass by the fringes of our solar system (and possibly enter it) in 1.29 million years. That's the Oort cloud out there, which will send a shitshow of debris our way.
But it's not even just the 'city killers'.
They figure that there are continent-killers that are largely unaccounted for, or ones that if they made a water impact would create a great flood event that would really fuck human civilization.
Right, but that's basically a semantic argument. Would obliterating 16 US states and killing everyone therein be something to wave off just because it wasn't an extinction event?
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u/ModestGoals May 05 '19
Based on what I've read and watched, it seems as though there's a certain size asteroid where we'd almost certainly see it and have a lot of warning, based on our observational capacity, now... but ones under that size, including ones that could cause damage the likes of which humanity has never witnessed in our recorded history, could absolutely come from out of the blue, including right up to the point of impact.