Since the dawn of civilisation and the dreaming up of our early creation myths, the philosophical and scientific debate of the origin of life has enchanted people worldwide. Since the thousands of years when early man prayed to sky gods have we got any closer from determining how life originated on earth? And can we even prove any of the theories through the scientific method?
The most widely held theory is that of abiogenesis. This is the idea that the conditions present on early earth when life was beginning, such as the electrical activity and dense atmosphere, resulted in the spontaneous creation of the building blocks of life. When these early conditions were replicated in the lab, in the iconic Urey-Miller experiment of 1953, some ingredients for life, such as amino acids, were seen.
The one major problem with this theory is that just as in cooking, adding the ingredients together doesn’t automatically make the meal. Life is amazingly complex and intricate. Having the building blocks doesn’t account for how they organised themselves into the patterns that can be call life.
Scientists are working to fill in this gap, producing theories based on the original abiogenesis. These ideas attempt to explain how order was achieved. These include the Deep Sea Vent hypothesis, the Coenzyme and RNA world hypothesis, and the Iron-Sulfur World theory. Other theories stray away from the abiogenesis idea, such as Autocatalysis Clay hypothesis, Gold’s “Deep-Hot Biosphere” model, Lipid world and Polyphosphates, to name a few.
One theory looks beyond the earth for the origin of life. This is known as panspermia, the theory that life originated in space. The main proof behind the theory is the presence of dead microbes and fossils found in debris in the stratosphere. However this evidence has faced harsh criticism from the scientific world.
There are many questions yet to be answered by Panspermia. In the theory, life, in the form of microbes, came to earth piggybacking on meteors and asteroids. How did the microbes survive the harsh conditions of space, and the harsher conditions whilst entering or exiting the atmosphere? Where did they come from? How did they then survive on a barren planet enough to divide and evolve? This theory doesn’t really solve the fundamental question of where life originated, but it does extend the time for which life can form over. In the history of the universe, earth is relatively new.
Science is yet to form a watertight theory on the origin in life, and there is question if it ever will. The many different ideas debate over which is the closest to what events occurred millions of years ago. Without concrete evidence all we can do is continue to develop these ideas based on theories and assumptions.