Planet revision again

Live an learn; since I wrote the entry on planets I have done just that.  The first period of time on the Earth is called the Hadeon Eon, the time of heavy bombardment in the solar system.  It stretches from 4.5 billion years ago to 3.8 billion years ago.  This is the time when the earth first formed until when Jupiter finally cleared out all the major asteroids out of the inner solar system.  Fifty million years into this Eon, a Mars sized planetoid collided with the Earth.  The core of this object was added to our own and its mantle and some of our own left the planet and became the Moon.

I am going to now make stuff up that I have no support in science, but I could be correct.  Before the collision the earth did not have enough gravity to retain an atmosphere, but after the collision it did.  This sounds like total BS, and probably is.  Our atmosphere came from volcanoes.  Volcanic gase contains mostly carbon dioxide and water vapour and this water vapor is where our oceans came from.  Fifty million years was not enough time to create oceans.  

In any case, during the period of heavy bombardment, the Earth was in constant flux.  What does that mean?  The oceans were present and life may have started several times in the oceans only for a large impact to vapourize the oceans and start the life process to zero again.  The oldest Rocks are from this Eon.  There are three regions  that contain very old rocks, of at least 4.3 billion years, one in Australia and two in Canada.  I used to take pride in this, but now I do not; why take pride in an accident of birth and civilization?