Introduction

According to the discovery and aging of zircon crystals, and the precise alignment of the resulting conditions on earth with Creation Day 1 (Genesis 1:4, Psalm 104:6, Job 38:9), it would seem that Day 1 ended around 3.9 Ga (billion years ago). Day 2 seems to have been a continuation of that process. So, when was Day 2?

Day 1 was 3.9 Ga

Day 2 had to have occurred at some point after the rains of Day 1 let up, but before dry land appeared, which happened on Day 3.

According to mainstream science, dry land first appeared around 2.5 Ga, during the Proterezoic, hence placing Day 2 somewhere between 3.9 Ga and 2.5 Ga. This is known as the Archaen Period. But, can we focus in a bit more?

Honing in a Date for Day 2

The one event that appears to sufficiently demonstrate the existance of a vault (i.e., the firmament) is the discovery of fossilized bacteria, around 3.5 Ga. This falls somewhere within the Early Archaen Period, which was around 3.8 Ga to 3.5 Ga. It would seem that by 3.5 Ga, the world experienced a sufficient change that life was now sustainable, and that conditions allowed this life to fossilize. This is very strong evidence for a firmament, and gives us a range for the dating of Day 2. As described in the “Plant Evolution Tour” by Adam Dimech [emphasis added]...

"Cherts and shales have also provided evidence for the world’s first life forms. Some of the most significant cherts are also located in Western Australia; the Warrwoona Group. Carbonaceous cherts there date back to 3500-3300Ma, and contain filamentous and conical structures which are likely to be early life forms, probably photoautotrophic cyanobacteria. This is very significant for a study of plant evolution because plants derive their energy from photosynthesis; a process where light is converted into chemical energy and carbon dioxide into oxygen. The presence of cyanobacteria dating back to 3500Ma indicates the age of photosynthesis."

Conclusions

As you can see, scientists cannot provide a precise date for the onset of photosynthesis. However, with some estimating 3.8 Ga to 3.5 Ga, and other estimating 3.5 Ga to 3.3 Ga, we do see some overlap. This provides a potential range for Day 2... around 3.5 Ga.