There's no authoritatively correct reference for what "slow" or "fast" should mean in extraterrestrial contexts, however, I think it makes sense to look at it like this:
Suppose you were watching a (CGI) movie or a video of a meteor hitting Earth, with the whole globe on screen.
The diameter of the Earth is almost 13,000 km. So a meteor(oid) going even 70 km/s is going to take 3 minutes to hit from one diameter away.
It should look like it's barely moving on a planetary scale.
Suppose you were watching a (CGI) movie or a video of a meteor hitting Earth, with the whole globe on screen.
The diameter of the Earth is almost 13,000 km. So a meteor(oid) going even 70 km/s is going to take 3 minutes to hit from one diameter away.
It should look like it's barely moving on a planetary scale.