All plants on Earth may owe their existence to a spooky trick of quantum physics

By: Sarah KramerTech Insider

Plants are possibly the most fundamental life form on Earth, supplying food and oxygen to ecosystems around the planet.

And yet many aspects of their leafy lives remain mysterious.

Photosynthesis — the process plants use to turn light into energy — is especially something of an enigma. Scientists have puzzled for years about how the process can capture roughly 95% of energy from in sunlight in just one million-billionth of a second.

Compare that to our best solar panels, which work much differently than photosynthesis; they don't even come close, changing just 40% of sunlight into energy.

But a paper published in the journal Nature in 2007, which we learned about from a BBC Earth story and is still making the rounds among scientists, suggests that the key to photosynthesis might work only due to a totally bizarre effect of quantum physics.

Quantum physics governs the universe on incredibly small scales — including at the level of molecules inside chloroplasts, the structures inside plants where photosynthesis happens. At that level, particles don't behave the way that matter we interact with every day does.

For example, the position of particles in quantum physics isn't described by a set location, but by the mathematical probability that will be in any particular location.

When you add these probabilities together, you end up with the spooky principle of superposition — particles existing in several places and states at once.

Photosynthesis takes abundant photons of sunlight and puts it to use with incredible speed and efficiency, losing almost no energy in the process. So what the photons may actually be doing is going through all the pathways in the leaf simultaneously. That includes the most efficient one, which will deliver the maximum amount of energy in the minimal of time.

This means plant chloroplasts somehow "know" how to pick the most optimal path for a photon to harvest its energy.

How plants do this remains unknown, but probing that mind-blowing mystery stands to lead to the next breakthrough in solar power.


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