(4 of 42 slides)
This is our Unhappy Moon - bombarded by particles, large and small, from space. Micrometeorites can be so small that they cannot be seen by the naked eye, but with velocities up to 200,000 km/hr, they possess sufficient energy to crush and even melt the silicate soil fragments.
(5 of 42 slides)
(6 of 42 slides)
