Planetary scientists are more interested in Mars. NASA has set a goal of launching a manned trip to Mars. They are also sending explorers to the planet’s surface and building technologies to prepare for human exploration.
According to a recent research study led by experts from the University of Arizona, if there was ever life on Mars – and that’s a big “if” – conditions during the planet’s infancy would have most likely supported it.
The increased focus on Mars has resulted in some exciting discoveries. Most recently that life may have lived on the planet before the climatic change. That’s the conclusion of a new study; keep reading to learn more.
1. Form of life on Mars; Microbes
Mars would almost certainly have been habitable for methanogenic microorganisms. These microbes are found at hydrothermal vents and along ocean floor fissures. They support vast ecosystems that have evolved to withstand crushing water pressures, utter darkness, and near-freezing temperatures. They produce methane as a byproduct in hypoxic conditions.
2. Emitted Gases May Have Led to Catastrophic Climate Change
Early Mars had methanogenic microbes that survive by transferring chemical energy from their surroundings and emitting methane as waste. These bacteria caused the planet’s surface to cool, making it inhospitable and forcing life deeper underground, eventually leading to extinction.
According to our findings, biological activity on Mars would have drastically altered the planet’s atmosphere in a matter of tens or hundreds of thousands of years. Sauterey said, “Microbes would have substantially lowered the planet’s climate by extracting hydrogen from the atmosphere.”
3. Younger Mars had a friendly atmosphere
About 4 billion years ago, Earth’s red and smaller neighbors have been more friendly to life. It has been rich in carbon dioxide and hydrogen. But now, research studies published in the journal Nature Astronomy, show that Mars is now cold and dry with an uncertain atmosphere to live in. As a result, any type of life on the surface is exceedingly impossible.
Most Mars researchers think that the planet used to have a much denser atmosphere than it does now. According to Regis Ferrière, a professor in the University of Arizona Department of Ecology and Evolutionary Biology and one of the paper’s two senior authors, it would have likely provided a temperate environment that allowed water to flow and, maybe, microbial life to thrive.
The authors do not claim that life existed on early Mars. But, according to Ferrière, early Mars would very likely have been friendly to methanogenic microorganisms.
4. The Atmosphere of Earth May Have Been Closer to Mars
“We believe Mars was slightly cooler than Earth at the time. But it is not nearly as cold as it is now, with typical temperatures likely hovering over the freezing point of water,” he said. “The modern Mars has been depicted as an ice cube coated in dust. Therefore, we envision early Mars as a rocky planet with a porous crust, saturated in liquid water. This saturated water would have likely created lakes and rivers, and possibly seas or oceans.”
According to spectroscopic observations of rocks exposed on Mars’ surface, that water would have been exceedingly salty.
5. How the Researchers Came to Their Conclusions
Most hydrogen on Earth is bound up with water. It is rarely observed on its own, except in isolated situations such as hydrothermal vents. According to the authors, its abundance in the Martian atmosphere could have given an abundant supply of energy for methanogenic microorganisms. This could happen when conditions would have been more favorable to life.
According to Ferrière, early Mars would have been significantly different from what it is today, moving toward warm and wet rather than cold and dry due to high quantities of hydrogen and carbon dioxide, both of which are strong greenhouse gases that trap heat in the atmosphere.
6. Microbes flourished in the planet’s crust
The scientists used models that estimate the temperatures at the surface and in the crust for a specific air composition. The purpose of this model is to mimic the conditions that early lifeforms would have encountered on Mars. They then merged the data with an ecosystem model that they created to determine whether biological species could have survived in their particular habitat. It also determined how they would have changed it over time.
Boris Sauterey, the paper’s first author said, “Once we had created our model, we put it to work in the Martian crust,”. He was a postdoctoral scholar in Ferrière’s group before moving on to the Sorbonne Université in Paris. “This allowed us to assess the plausibility of a Martian subsurface ecology.” And, if such a biosphere existed, how would it have altered the chemistry of the Martian crust, and how would these crustal activities have changed the chemical composition of the atmosphere?”
“Our goal was to build a replica of the Martian crust with its combination of rock and salty water, let gases from the atmosphere permeate into the ground, and see if methanogens could live with that,” said Ferrière, who also works at Paris Sciences & Lettres University in Paris. “And the overall answer is that these bacteria may have made a living in the planet’s crust.”
“The problem is that even on early Mars, the surface was still quite cold, so bacteria would have had to descend deeper into the crust to find habitable temperatures,” he explained.
“The question is, how deep does biology have to travel to establish the correct balance between temperature and the availability of chemicals from the atmosphere required for growth?”.
They were able to forecast the climatic feedback of the change in atmospheric composition induced by the biological activity of these bacteria. This could be done by altering their model to take into account how processes operating above and below ground influence each other.
In an unexpected twist, the study revealed that ancient Martian life may have flourished at first. Its chemical feedback to the atmosphere would have triggered a global cooling of the planet. This eventually renders its surface uninhabitable and drives life deeper and deeper underground, possibly to extinction.
As a result of biological activity, the early Mars’ surface would have quickly become glacial. In other words, climate change caused by Martian life may have contributed to the planet’s surface becoming inhospitable early on.
7. Hellas Planitia
Future explorers of Mars said that they have identified Hellas Planitia. It is an extensive plain that is carved out by a large comet or asteroid that impacts very early in Mars’ history. It is a particularly promising site to scour for evidence of past life. The location’s topography continues to generate some of Mars’ most violent dust storms, which makes the area too dangerous to be explored by an autonomous rover.
For the time being, the team is concentrating its efforts on modern Mars. While NASA’s Curiosity rover and the European Space Agency’s Mars Express satellite have detected elevated levels of methane in the atmosphere, such spikes do raise the intriguing possibility that lifeforms such as methanogens may have survived in isolated pockets on Mars, deep underground – oases of alien life in an otherwise hostile world.
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