If one micrometeorite (a sphere with a diameter of 1.0 multiplied by 10-6) struck each square meter of the moon each second, it would take many years to cover the moon with micrometeorites to a depth of 1.5 m. Consider a cubic box, 1.5 m on a side, on the moon. Estimate how long it would take to completely fill the box with micrometeorites if one micrometeorite landed in the box each second.

1 answer

The diameter is 10^-6 what? meters? That is what I will assume.

Assume each micrometeorite occupies a volume of (10^-6 m)^3 = 10^-18 m That is close enough, since they will not be the same size and not perfectly packed in a hexagonal array. About half the space will be void.

Divide the (1.5)^3 m^3 = 3.38 m^3 box by 10^-18 for the number of particles needed to fill the box. It will take that many seconds to fill. My calculated number exceeds the age of the moon, and the universe