In late 2013 and early 2014, NASA’s Curiosity rover detected an sudden spike in methane on Mars — 10 instances the standard degree. Inside just a few months, the spike pale. Since then, Curiosity has recorded six extra of those occasions, however international measurements of the fuel have failed to seek out something conclusive.
The reason for these mysterious methane spikes could also be an odd type of alien life — or it might simply be fascinating chemistry. Both manner, one thing odd is occurring on the Pink Planet.
Methane is comparatively simple: It is only a carbon atom hooked up to 4 hydrogen atoms, and each of these components are extremely widespread in the universe. On Mars, there’s loads of carbon to go round — it types the spine of carbon dioxide, the primary part of that planet’s thin-but-persistent ambiance.
Hydrogen can be widespread on Mars — and actually in every single place else within the universe. However hydrogen is a really pleasant component and is often discovered sure up in another molecule. To make methane, that hydrogen must be freed.
Associated: Mars’ subsurface is ‘burping’ out methane, and scientists aren’t certain why
Fortunately, on Earth, we already know of a course of to generate free hydrogen. When water interacts with iron- and magnesium-rich rocks, oxidation can launch hydrogen. One in every of these processes entails olivine, a mineral that is wealthy in each iron and magnesium. When olivine and water work together, it results in a course of known as serpentinization. The case of olivine is particularly fascinating as a result of it is a quite common mineral on Mars.
As soon as free, the hydrogen can, underneath the best circumstances, react with carbon dioxide by means of a course of known as Fischer-Tropsch synthesis, producing methane. However for all of this to work, Mars wants liquid water. Though the planet was as soon as water-rich, as evidenced by the dried-up riverbeds and erosion, it is definitely very dry now. The one place the place liquid water might exist on Mars is deep underground, sprinkled right here and there in microscopic cracks and crevices, very similar to it’s in Earth’s mantle. If liquid water does exist deep underground, then that water may have the ability to react with minerals and launch hydrogen. The hydrogen might then go on to react with carbon dioxide and produce methane.
However what might set off the sudden bursts of methane that Curiosity measured? A purely geologic course of has issue making fast ramp-ups of methane, as a result of Mars is not geologically energetic the identical manner Earth is.
So perhaps Mars is “alive.” Definitely there isn’t a life on the floor there now, though it is doable that Mars was dwelling to life in its distant previous. If Mars nonetheless retains some dwelling creatures, they need to additionally reside deep underground, removed from the reaches of our present observations.
And that Martian life would not have the ability to survive on photosynthesis, as a result of daylight cannot penetrate to these depths. Nor might it use oxygen, as there is not sufficient free oxygen on that planet to maintain it. So any hidden life would not be like most dwelling creatures on Earth.
However fortunately, Earth has such all kinds of life-forms that there’s a class of organisms that might match the invoice: methanogens. These single-celled organisms have very odd metabolisms — notably, they “eat” hydrogen and excrete methane.
On this situation, methanogens would take the place of chemical processes to provide methane on Mars. Like all dwelling creatures on Earth, they’d nonetheless want carbon, and they might nonetheless want liquid water to react with iron-rich minerals to generate liberated hydrogen. However from there, the methanogens would devour the hydrogen and produce methane as a waste fuel.
The temporary spikes of methane noticed on Mars are inclined to observe the seasons, with late spring and early summer time seeming to have the best ranges of atmospheric methane. Whereas introducing life as a speculation to elucidate some astronomical thriller is all the time a attain, on this case it is a pure match, since many dwelling organisms naturally reply to seasonal modifications.
Nonetheless, there isn’t a different proof for all times on the Pink Planet. And there aren’t any indicators of different byproducts of methanogens, like extra ranges of ethane. So it isn’t a slam-dunk case for life on Mars.
Plus, there must be some mechanism for destroying methane on Mars as rapidly because it seems. Whereas methane is unstable within the Martian ambiance, present established strategies, like Ub dissociation and oxidation, take centuries to play out. So no matter technique we concoct to elucidate the sudden look of methane must be matched with a way for eradicating it.
No matter’s occurring on Mars, the seasonal rise and fall of methane is an indication that there’s far more to find out about our neighboring planet and that it is holding many secrets and techniques beneath its floor.
