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A new study revealed that early life on Mars may have killed itself during its infancy on the Red Planet, which is similar to what happened on Earth, even though life on our planet managed to evolve and continue.
Evidence indicates that Mars was warm and humid and had an atmosphere, between 3.7 billion and 4.1 billion years ago, and it also had water. If this is true, then perhaps Mars was habitable (although this does not necessarily mean that it was inhabited).
The new study, published in the journal Nature Astronomy, showed that early Mars may have been hospitable to a type of organism known as methanogens that thrived in the harsh environments on Earth. These organisms live in places such as hydrothermal vents on the ocean floor, where they divert chemical energy from their environment and release methane as a waste product.
The study, which was based on computer simulations, shows that microbes may have thrived in the shiny porous rocks that protect them from ultraviolet and cosmic rays. The underground environment would also have provided a diffused atmosphere and a cool temperature that allowed the methanogens to persist.
But the scientists found that this increased number of microbes could not continue, due to the amounts of methane they were producing. Within “a few tens or hundreds of thousands of years”, Mars’ atmosphere would have “completely changed” as the Red Planet experienced extreme cold, said Boris Soteri, the study’s lead author.
The cooling occurred due to the effect of greenhouse gases. Hydrogen and carbon dioxide worked to keep the planet warm, but because methane was essentially displacing hydrogen, it became more difficult to trap heat, allowing the planet to cool.
He continued, “The problem that these microbes may have faced after that is that the Martian atmosphere has almost disappeared, and has become completely weak, which leads to a lack of its energy source.”
Unlike Mars, Earth’s atmosphere is made mostly of nitrogen, with a smaller portion made of oxygen. These molecules interact differently than those in the Martian atmosphere, which is why when methane is released to Earth, it traps heat on the planet. The effect of greenhouse gases on Earth is not caused by microbes but by people burning fossil fuels.