[davidcuddeback]

> On the other hand, what's the chance of something like this happening with a much bigger asteroid.

Bigger asteroids are easier to see.

[ithkuil]

that's right.

another metric that affects the ... impact ... of such an event is also the speed of the asteroid. Unlike size, I suspect higher speeds would make it harder to spot (and once spotted there would be less time to take action)

[BurningFrog]

Asteroids are just as visible at any speed.

Though warning times will be shorter the higher the relative speed is.