Question: What would happen if the moon started cracking and pieces of it flew towards the Earth?

Iain Bethune answered on 23 Jun 2015:

Depends how big they were! Small particles of dust burn up in our atmosphere all the time, several tons every day. Larger meteoroids sometimes made it through the atmosphere without being vapourised by frictional heating and fall to earth as meteorites. Many of these were once part of the moon, Mars, or other rocky planets and were blasted loose by huge collisions long ago.

If you want to try seeing what would happen if larger things hit the Earth, you can experiment with this website: http://www.purdue.edu/impactearth/