Last updated March 8, 2018 at 10:11 am
The search for extra-terrestrial life has had a boost, with two new papers finding life is able to exist on Mars and Enceladus
NASA’s Cassini spacecraft captured this image of Enceladus on Nov. 30, 2010. The water and gas jets of Enceladus are clearly visible. Image Credit: NASA/JPL-Caltech/Space Science Institute
In the ongoing search for extra-terrestrial life, researchers keep looking towards Enceladus – the icy moon of Saturn – and Mars. This is for a good reason, both planets have conditions which are thought to be able to support life.
Adding weight to this search is two papers released this week which show that life is capable of being supported on both planets, by taking a closer look on Earth.
On Oct. 9, 2008, just after coming within 25 kilometers (15.6 miles) of the surface of Enceladus, NASA’s Cassini captured this stunning mosaic as the spacecraft sped away from this geologically active moon of Saturn. Image Credit: NASA/JPL/Space Science Institute
The farting bacteria of Enceladus
Enceladus is a hot spot in the search for potential extra-terrestrial life, as it harbours a watery ocean beneath its icy crust, hydrothermal activity at its south pole, and contains various compounds including methane, carbon dioxide, ammonia, and molecular hydrogen.
These gases in are interesting for scientists, as they can be produced or used for growth by microbes like bacteria. The fact that methane is present could be a sign of life that produces methane as a waste product.
Now, researchers from Austria have found that certain microbes can thrive using carbon dioxide and molecular hydrogen for growth – and release methane back into the atmosphere.
They grew three of these microorganisms in a lab simulating gas conditions and pressures similar to those predicted on Enceladus. One of the microbes in particular, called Methanothermococcus okinawensis, grew and produced methane even in the presence of compounds that inhibit the growth of other bacteria, such as formaldehyde, ammonia, or carbon monoxide.
In addition, they found that geological processes in Enceladus’s core may produce enough hydrogen gas to support the microbes.
This finding is, of course, all in theory. While the research does show it is possible for methane-producing bacteria to grow on Enceladus, it is still not known for sure if the bacteria is present on the moon. The methane on Enceladus could be produced by non-biological processes, such as geochemical reactions.
However, the finding does suggest that it is worthwhile continuing the search on Enceladus for bacteria farts.
The study has been published in Nature
South America gives hints to life on Mars
Meanwhile in South America, researchers have, for the first time, seen life rebounding in the world’s driest desert, the Atacama.
A comparison of the These are the surfaces of Mars and the Atacama Desert. Credit: NASA (left) and Alessandro Airo, TU Berlin (right)
While that might not seem significant, it demonstrates that life could also be lurking in the soils of Mars, just waiting for the right conditions.
In the Atacama it can go decades without rain. However, the researchers found that specialized bacteria are able to live in the soil, going dormant for decades without water, and then reactivating and reproducing when it rains.
“It has always fascinated me to go to the places where people don’t think anything could possibly survive and discover that life has somehow found a way to make it work,” lead researcher Dirk Schulze-Makuch said. “Jurassic Park references aside, our research tell us that if life can persist in Earth’s driest environment there is a good chance it could be hanging in there on Mars in a similar fashion.”
When Schulze-Makuch and his team went to the Atacama for the first time in 2015 to study how organisms survive in the soil of Earth’s driest environment, the craziest of things happened.
It rained.
After the extremely rare shower, the researchers detected an explosion of biological activity in the Atacama soil.
But while life in the driest regions of Earth is tough, the Martian surface is an even harsher environment.
It is akin to a drier and much colder version of the Atacama Desert. However it wasn’t always this way.
Billions of years ago, Mars had small oceans and lakes where early lifeforms may have thrived. As the planet dried up and grew colder, these organisms could have evolved many of the adaptations lifeforms in the Atacama soil use to survive on Earth. If it happened here, it could have happened there, they suggest.
And that means that life on Mars could be waiting, ready to be rediscovered when the conditions are right.
The study has been published in the Proceedings of the National Academy of Sciences
