1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000BC-3000000BC

1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000BC: It is very dark!

10 100 5325 76 Bc: It is still very dark!

3,000,000 BC: It is very Dark!

Now see: 3,000,000-4004 BC.