Genesis 1:6 to 8 - Creation of the firmament
Then God said, “Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.” - Genesis 1:6
At the beginning of Day 2, it was still raining… hard. An atmosphere was beginning to form, and Jesus had seen to it that no more large meteors would decimate it. It was sometime after 3.9 Ga, though probably before 3.85Ga, when the first signs of life would be fossilized.
The rain was like a sheet of water connecting the clouds to the oceans, until God said to Jesus to let a firmament form. Eventually, the rain let up. There were still clouds, but there was now a space between them and ocean.
Thus God made the firmament, and divided the waters where were under the firmament from the waters which were above the firmament; and it was so. - Genesis 1:7
It is unclear whether there were solid clouds or scattered. With little to no Oxygen in the atmosphere yet, things were pretty hazy, so the view of the clouds could have been encumbered. In any case, the brightness of the sun’s light was undoubtedly more brilliant than before.
And God called the firmament Heaven. - Genesis 1:8a
Eventually, Jesus stopped watching the earth rotate beneath Him, and allowed the night to come.
So the evening and the morning were the second day. - Genesis 1:8b