The Genesis gap theory says Satan was thrown out of heaven, then
destroyed the pre Adamic earth between Genesis 1:1 and 1:2.
  This cannot be true because that was supposedly over 6000 years
before Satan will be thrown out of Heaven in Revelation chapter 12 at
mid tribulation to indwell the Antichrist.
  Satan cannot be thrown out of Heaven twice!
One of the great sins of todays' bible study is to bring into easily
understood chapters scriptures that totally change the context and
message of these easily understood chapters.
  As my best friend and former pastor bro Peter famously said
"changing the context is a pretext."
  In Genesis ch1:1 God makes a statement saying He created everything.
Then in 1:2 He begins to tell how he did it! Simple, and easily
understandable. There is both no need or justifiable reason to use a
crowbar to insert a whole bunch of other scriptures in there to create
a whole other creation. This is changing the context of the chapter.
   Unfortunately my church is going through this whole fuss right now  sigh.
Lewis

Genesis ch 12 says in the KJV:

6 And the woman fled into the wilderness, where she hath a place
prepared of God, that they should feed her there a thousand two
hundred and threescore days.

7And there was war in heaven: Michael and his angels fought against
the dragon; and the dragon fought and his angels,

8And prevailed not; neither was their place found any more in heaven.

9And the great dragon was cast out, that old serpent, called the
Devil, and Satan, which deceiveth the whole world: he was cast out
into the earth, and his angels were cast out with him.

10And I heard a loud voice saying in heaven, Now is come salvation,
and strength, and the kingdom of our God, and the power of his Christ:
for the accuser of our brethren is cast down, which accused them
before our God day and night.

11And they overcame him by the blood of the Lamb, and by the word of
their testimony; and they loved not their lives unto the death.

12Therefore rejoice, ye heavens, and ye that dwell in them. Woe to the
inhabiters of the earth and of the sea! for the devil is come down
unto you, having great wrath, because he knoweth that he hath but a
short time.