In the pursuit of discovering life beyond Earth, scientists are expanding their exploration beyond the conventional notion of green-hued alien entities. Recent research suggests that potential extraterrestrial life forms could actually be purple, specifically referring to purple bacteria. Astronomers are particularly intrigued by these lavender-colored microbes due to their distinctive chemical composition, which may enable them to thrive on distant planets orbiting dim red stars.
Led by researchers from Cornell University, the study seeks to enhance our understanding of potential indicators of life beyond Earth’s familiar green chlorophyll-based organisms. Co-author Lisa Kaltenegger notes that the resilience and adaptability of purple bacteria across diverse environments suggest that on various worlds, purple could emerge as a significant biological hue, as reported by Space.
The evolutionary history of life on Earth offers valuable insights into the potential evolution of life elsewhere. Approximately 2.4 billion years ago, cyanobacteria, the earliest known photosynthesizing organisms, began utilizing chlorophyll to harness sunlight, a pivotal development that facilitated the release of oxygen into Earth’s atmosphere as a metabolic byproduct.
Before the advent of chlorophyll-based photosynthesis, microorganisms relied on a purple pigment molecule known as retinal for energy production. Researchers speculate that the presence of this molecule on other planets could create a distinctive signature detectable by advanced telescopes.
Lúgia Fonseca Coelho, the study’s lead author from the Carl Sagan Institute in New York, highlights the adaptability of purple bacteria. In environments devoid of competition from green plants and algae, these bacteria could potentially thrive under the illumination of a red sun, optimizing conditions for photosynthesis.
The study underscores the significance of broadening the search for life beyond Earth’s conventional green organisms. With ongoing advancements in telescope technology, scientists are optimistic about detecting unique signatures indicative of purple bacteria on distant planets, offering a promising pathway toward unraveling the mysteries of the cosmos.
