Human beings have been puzzling over what Earth without life looked like for a long time. Christians believe there was one all-powerful God that spoke creation into existence from nothing. Ancient Greeks theorized about a primordial being named Khaos, a dark void that is the anchor of reality between Earth and their hell, Tartarus. Ancient Egyptians pictured their sun god, Atum, being asleep drifting in a sea named Nun since before time, suddenly waking up and creating a “first island” of land. Today, we know that Earth began as a rocky and inhabitable planet before several environmental changes took place, allowing for life to develop on Earth. Many stories try to explain what we still do not know today: how life came out of a world without it.

Charles Darwin gave rise to what would later become known by Alexander Olapin as the primordial soup theory. Taking place between 3.7 and 4 billion years ago, primordial soup refers to the exact conditions in which life began to evolve. Compounds began to form monomers, then polymers, and finally protobionts: a cell-like structure that can replicate itself, but is not considered a living organism. 

The Miller-Urey experiment in 1952 attempted to find if this was feasible. The theory was that if the early Earth’s conditions were closely replicated, life would eventually evolve in this environment. The scientists chose their “ingredients”: the atmosphere then was low in oxygen but rich in water and compounds such as ammonia and methane. Primordial soup ended up being an apt name, as they then added energy in the form of electricity to spur the materials into action. This replicated abiotic sources of energy at the time such as storms and volcanic eruptions. Within just one week, amino acids had begun to form. This experiment has been replicated many times in different environments and the addition of materials such as calcium and iron, which are found in small amounts in living organisms. 

However, water remained an under-utilized part of this equation. In the last decade, scientists had a theory: before cells developed their cell walls, they may have been contained in water droplets. Water has a high surface tension, meaning that these bubbles would not have collapsed easily. However, when shaken in an experiment, the droplets can split the RNA inside of them, which may have been the earliest form of replication. Dr. Aman Agrawal, a chemical engineer, was working with RNA droplets with the hope of having them produce important compounds in 2018. A test tube was left alone for four months from this experiment, and its contents were intriguing.

The water and excess compounds had combined to create a milky substance, and the water had kept the droplets stable. Simply leaving the components in water and shaking them would create RNA droplets. Water, and not air, was the background from which life likely evolved. Today, the experiment is being replicated with different water concentrations and acidity levels, and stable RNA droplets are being made by simply combining the right proportions and shaking. This is bridging a large gap between abiotic materials and cells in the history of evolution.