Life in a Bubble

Referring to someone as “living in a bubble” implies being out of touch with reality. But could all of reality, all of life, have once begun inside a bubble?

The current thought is that for life to begin, chemical reactions on the ancient Earth must have given rise to simple organic molecules. These molecules  then became self-replicating, sewing the seeds of evolution and providing the spark of life. The exact process by which this occurred is a mystery. Piecing together this mechanism and understanding the origin of life, is one of the greatest challenges facing modern science.  

One of the issues is that in order for a chemical reaction to occur, a significant energy barrier must be overcome. When two reactant molecules combine and form one product molecule, the system becomes more ordered. This means the entropy  has decreased, a violation of the second law of thermodynamics. To combine two molecules, energy has to be put in to overcome the barrier to reaction.

How could this have occurred on the early Earth?

In the late ’90s, it was found that aerosol particles in the atmosphere contained a large number of organic compounds. A mechanism was suggested of how these micro-meter sized droplets could be a precursor to life. Now, new research has shown that reactions inside microcompartments – or bubbles – can increase the rate of unfavorable reactions.

The study demonstrated the effects of compartmentalising reactant molecules inside a micro-meter sized drop of water. The smaller the droplet, the faster the product formed.  By using a mathematical model to explain the experimental results, it was shown that when a molecule binds to the inner surface of a drop, the amount of space available to it is limited and its movement is restricted. As a result, the molecule is more likely to react, without the need for a catalyst. Once reaction has occurred, the product diffuses back into the bulk solution.

This mechanism could help to explain how the very first organic molecules formed. Deep inside hydrothermal vents, it may be that all of life began suspended on the surface of a bubble.

Bubble Pic

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For more on this story, check out the original paper from Physical Review Letters. An brief summary also appeared in Nature about the research.

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