two asteroid mysteries

Part 2 Mystery 2

It is difficult to make a credible generalization
based on a single sample, especially if that sample
tends to contradict the generalization. But I will
try anyway:

The old fashioned way to clean a rug was to hang it
on a clothes line and to beat it with a stick. With
each impact some of the dirt would fly out and fall
to the ground. Also, most are familiar with the image
of a boxer at the instant he is hit with an undercut.
Droplets of sweat fly out of his face in all directions.
What does this have to do with an asteroid? Well
any impact on a body will cause loose material to fly
out of the body as a reaction to the vibration
produced by the impact. On low gravity asteroids, the
volume of matter lost to space would be greater than the
volume of matter created by the impact. Continued
collisions would tend to produce a bare surface not unlike
that found in the High Sierra near Tioga Pass. (obviously
the origin there is different). There is a body mass (of an
asteroid) for which the volume of ejected matter is LESS
than that created by the impact. In my opinion, however
the mass of Eros, on which we actually observed the presence
of boulders of varying sizes is too small to accumulate
surface free objects. So where did the boulders come from?
My guess is that they are of relatively recent origin,
say a few hundreds of millions of years. The mystery would
then be how did this came to be?

They probably were in a similar orbit and made a soft landing. Some may
have been thrown up from Eros by an impact and have fallen down again.
I imagine that dust will be more easily thrown up from Eros than
somewhat larger objects. This does not seem all that mysterious to me.
Neither do I think that the
volume of matter lost to space would always be greater than the
volume of matter created by the impact. Most impacts will be from
smaller particles like dust and protons and helium and I must assume
that at least some asteroids gain mass because of it.