The atmosphere of Venus could harbor extraterrestrial life in the form of microbes, according to a new study from the University of Wisconsin-Madison. This idea, which has gone in and out of favor as astronomers learn more about Venus, could see a resurgence with these new ideas.
Sanjay Limaye of The Space Science and Engineering Center at the university believes that Venus could be home to microscopic life, hovering in the upper atmosphere of Earth’s twin planet.
“Venus has had plenty of time to evolve life on its own. That’s much longer than is believed to have occurred on Mars,” Limaye explained.
Venus is nearly as large and massive as the Earth, and is only one planet closer to the Sun than our home. However, vast amounts of carbon dioxide in the atmosphere has resulted in a runaway greenhouse effect on that world, leading to Hellish conditions on the surface. On the surface of that planet, temperatures can reach temperatures of 465 Celsius (or 870 Fahrenheit) or more, making Venus the hottest planet in the Solar System.
The atmosphere, consisting almost entirely of carbon dioxide, crushes anything on the surface with air pressures greater than 90 times what we experience on Earth. This is approximately the same pressure as a diver would experience at 90 meters, or 300 feet, underwater.
On Venus, just as on Earth, both the temperature and pressure of the atmosphere drop as one climbs above the surface.
On our home planet, bacteria and other microbes may be lifted as high was 25 miles into the atmosphere through the power of winds. Similar actions on Venus may also send microorganisms into the air. Here, temperatures could be similar to those on Earth, and pressures significantly lower than on the surface of the scorched planet.
Limaye and his team speculate that life in the atmosphere of Venus could resemble extremophiles, organisms found here on Earth that thrive in hot, acidic, of highly-alkaline environments that would kill most other forms of life. Dark patches seen in the atmosphere of Venus appear to be composed of particles about the same size as bacteria here on Earth, but astronomers are uncertain of the composition of these constantly-changing formations.
Earlier studies “highlighted the potential for life in Venus’ cloud layers due to favorable chemical and physical conditions, including the presence of sulfur compounds, carbon dioxide (CO2), and water, and moderate temperatures and pressures,” researchers wrote in an article published in the journal Astrobiology.
Space agencies, including NASA, are currently exploring other bodies in the Solar System, including Mars, and two moons of Saturn, Titan and Enceladus, as well as Europa, the fourth-largest satellite of Jupiter.