Detecting life outside the Earth necessitates comprehension of measurable factors that signify the impact of life on a given environment.

These concrete factors that imply the existence of life are called biosignatures, which refer to any material brought about by a biological element. Now, scientists have found a technique that can help discover life on other planets based on this concept.

Edward Schwieterman, lead study author and a doctoral student at the University of Washington partnered with Charles Cockell, a University of Edinburgh astrobiologist, to investigate the reflectance of earthly objects with varying types of pigments. The two researchers also included organisms that do not necessitate the process of photosynthesis so that they can discover signs of biosignature features that they may possess, including its distinctiveness from organisms that do utilize photosynthesis.

"I was interested in doing biology in the lab and linking it to remotely detectable biosignatures, which are indications there is life on a planet based on observations that could be made from a space-based telescope or large ground-based telescope," Schwieterman said.

The researchers then used computer simulations and discovered that powerful telescopes that are currently being developed can detect the strong spectral signal of pigments that do not use photosynthesis, if they overlay sufficient surface areas of distant planets. Nonphotosynthetic pigments are those that do not only use light to process energy but for other purposes as well.

Generating energy is not the only function of pigments that absorb light on Earth. Other organisms may benefit from the protection these pigments can provide against the radiation of the sun. Pigments may also act as antioxidants to help organisms thrive successfully in extreme environmental events with increased heat, salt concentrations or acidity.

Schwieterman and Victoria Meadows, an astronomer from the University of Washington, then entered the collated data in the Virtual Planetary Laboratory, including the reactions of the clouds and atmosphere to create simulated planets that are covered with different levels of organisms. The experiment was able to present the wide range of differences between the spectral characteristics and band of colors of organisms that use nonphotosynthetic pigments.

Schwieterman admits that further investigation is necessary to identify the extent of planetary surface that can be covered with pigmented organisms, as well as the range of spectral characteristics that life on the planet generate. Looking at the types of coping mechanisms of other worlds, which may not be present on Earth, is also necessary, adds Schwieterman.

Photo: Robin Fernandes | Flickr

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