A conversation here reminded me of another useful #IntroToAstro resource, if you want to see how much danger Earth might be in from low-flying rocks. A lot of careful modeling went into the “Impact: Earth!” calculator at https://impact.ese.ic.ac.uk/ImpactEarth/. For a less bare-bones presentation (such as when I want to impress a class), there’s a version at https://www.purdue.edu/impactearth/.