Story highlights The earliest life forms on Earth may have been purple

This could give us insight into what life on exoplanets might look like

This feature is part of Colorscope, an award-winning series exploring our perception of color and its use across cultures, one shade at a time. See more here.

(CNN) The lush green planet that we call home may have actually looked purple in its earliest days, according to the "Purple Earth hypothesis."

No, this doesn't mean there were purple trees or purple grass or purple animals. It would have been before any multicellular organisms even evolved, when single-cell microorganisms dominated the planet and possibly created a purple hue that could be seen from space.

These purple organisms may have reigned supreme and existed in varying concentrations across the planet, said Shiladitya DasSarma, a microbiologist and professor at the University of Maryland. DasSarma has studied one of these microorganisms and created the Purple Earth hypothesis.

But what if Earth wasn't the only planet that experienced this purple phase? What if this hypothesis could give us insight into potential life on exoplanets, the planets outside our solar system? Scientists are in the process of figuring that out.

"That's where it might make a difference when we look at exoplanets. We would want to consider that the pigments on an alien planet might be different than what we have on modern Earth," DasSarma said. "And if the Purple Earth hypothesis was correct and there was a dominance of purple organisms in the early Earth, then we might be able to find another planet that's at an earlier stage of evolution of the planet, where the purple pigments might have dominated."

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