ASTRONOMERS FIND NEW EVIDENCE IN THE HUNT FOR ALIEN LIFE ON MARS AND VENUS
When scientists explore other worlds in our solar system, they depend on sophisticated instruments and rovers since human visits aren't yet possible. Their job is to discern whether they’re observing alien geology, unique chemistry, or signs of extraterrestrial life. Recently, there have been promising discoveries on Mars and Venus that hint at the possibility of life beyond Earth.
On Venus, astronomers have made significant strides by detecting two potential biosignatures in the planet’s atmosphere. The initial discovery was in 2020 when phosphine was identified through telescope observations, leading to excitement since phosphine on Earth is typically produced by microbes in oxygen-poor environments. Although subsequent attempts to replicate this finding initially failed, recent efforts using a new receiver on the James Clerk Maxwell Telescope in Hawaii have confirmed the presence of phosphine. Additionally, scientists have detected ammonia in the Venusian atmosphere, further bolstering the possibility of life. At a Royal Astronomical Society meeting in July 2024, researchers shared that they had collected 140 times more data than in previous observations, solidifying their findings.
Scientists theorize that if microbes exist on Venus, they might produce ammonia to neutralize the planet’s extreme acidity, creating more hospitable local environments. Over time, this ammonia could rise to the planet's cloud tops. However, despite these intriguing signs, there are alternative explanations given the harsh environmental conditions on Venus, and no definitive proof of life has been found yet.
Venus is similar to Earth in many ways—it’s almost the same size, rocky, and situated within the Sun’s habitable zone. However, it experienced a runaway greenhouse effect that drastically increased its temperatures, making it even hotter than Mercury despite being farther from the Sun. The average surface temperature on Venus is around 860°F, a condition that makes the planet a hellscape. These extreme conditions make the discovery of potential biosignatures like phosphine and ammonia particularly exciting because they suggest that some form of microbial life could theoretically exist there.
On Mars, NASA’s Perseverance rover has made a noteworthy discovery that could point to ancient Martian life. While exploring Neretva Vallis, an ancient riverbed in Jezero Crater, Perseverance found a rock dubbed “Chevaya Falls.” This rock contains organic compounds, evidence of water interactions, and signs of surface chemical reactions, all of which suggest that it could have once supported microbial life. The rock features large white calcium sulfate veins, reddish bands of hematite (which contributes to Mars' red color), and peculiar white splotches ringed in black.
During its 22nd rock core sampling on July 21, 2024, Perseverance found iron and phosphate in the rock's rings. While these discoveries are promising, confirming life on Mars requires more extensive study. Perseverance has already done as much as it can, and the next steps involve analyzing the rock samples on Earth. NASA’s Mars Sample Return mission, although uncertain, aims to bring these samples back home for detailed examination.
These discoveries on Venus and Mars offer tantalizing hints at the possibility of extraterrestrial life. On Venus, the detection of phosphine and ammonia sparks curiosity about microbial life in its acidic atmosphere. On Mars, the discovery of Chevaya Falls with its organic compounds and water interaction evidence suggests that ancient life might have existed there.
To explore these findings in greater detail, visit the Royal Astronomical Society's page for more information.
