What was earth like in the year 1000 BC?

The earth before 1000 bc

There was never a rainbow in the atmosphere before 1000 bc.

The earth never saw a rainbow until Noah did.

the following could never have happened before 1000 bc: Water molecules reflects the sunlight. Rainbows only appears when there are water in the air and light to be reflected in the water.

Geologists studying the landscape of the northwestern United States believe that as many as 100 catastrophic floods once washed over the area. One such flood is said to have roared through the region with a wall of water 2,000 feet high, traveling at 65 miles an hour, a flood of 500 cubic miles of water weighing more than two trillion tons.

Global flood?

If this is true then the earths atmosphere before the flood was drastically different than after the flood.

I believe that the earth had some kind of protection surrounding it that did not allow for any water molecules to penetrate the atmosphere. how could this be? I do not know that is why i am asking.