Since early life on earth might have had a purple tinge, scientists have proposed in a recent study that extraterrestrial life might be purple as well.
It is likely that extraterrestrial life could be purple, at least according to a new study published in the International Journal of Astrobiology by postdoctoral researcher Edward Schwieterman of the University of California, Riverside, and microbiologist Shiladitya DasSarma of the University of Maryland School of Medicine.
As Live Science report, early life here on Earth may have had a lavender hue to it as these purple organisms gradually found that they could create energy by harnessing the power of the sun, long before green plants figured out a way to do the same. Along these lines, DasSarma believes that extraterrestrial life could be doing the very same thing somewhere else.
Researchers already have discovered different ways to detect green life from space, and DasSarma believes that researchers need to start focusing on purple organisms now as well. The proposals that early life on Earth was purple is not really a new case, and DasSarma and his team initially proposed this hypothesis in 2007, leading them to anticipate that the same may be valid for extraterrestrial life, with it likely to also be purple.
The reason behind this claim is extremely straightforward. Photosynthesizing algae and plants harness the power of the sun for energy by using chlorophyll, but green light is not absorbed. Since green light is especially rich in energy, DasSarma and his team found this odd, thinking that possibly when chlorophyll synthesizers first began to evolve, there may have been something else that was able to use that part of the visible spectrum when chlorophyll photosynthesizers evolved.
Single-celled organisms, also referred to as Archaea, and microbes even now still use retinal light-harvesting and these purple organisms are so common on Earth that they have been discovered everywhere from the oceans to the surfaces of leaves to even the Antarctic Dry Valley. These pigments of retinal are also used by much more intricate organisms, and the discovery that these pigments are so common in various organisms suggests that their evolution probably started very early on Earth.
In any case, moving past the possibility that early life may have been purple on Earth, DasSarma and Schwieterman believe that purple organisms perform quite well, which implies that extraterrestrial purple life may likewise be thriving somewhere else. And if this is the case, and these alien organisms are using retinal pigments to harness their energy, astrobiologists should be able to find them only by looking for correct light signatures.
As Schwieterman clarified, “If these organisms were present in adequate densities on an exoplanet, those reflection properties would be engraved on that planet’s reflected light spectrum.”