In early summer 2019, the scientific world was elated. They thought that they had found an unmistakable sign of life on Mars. The Mars rover Curiosity detected significant concentrations of methane in the atmosphere of the planet.
Methane has always been considered to be the result of life’s processes. This could hence only mean one thing for the researchers.
There must be organisms that have produced this methane and they are on Mars so: “We found life on Mars”.
The presence of methane on Mars was not a novelty though. Mars Express, the orbiter of the Europan Space Agency, had detected molecular traces from orbit in 2003. But the Curiosity rover gave us a first direct measurement.
Yet, methane has been detected on almost all planets and many moons of the solar system. We also have a lot of spectroscopical measurements from objects and nebulae outside the Solar System. They show us that the methane molecule is prevalent all throughout the cosmos.
Is life everywhere? Were the cryo-lakes on the Saturnian moon Titan produced by hardy little buggers in space? Average temperatures there is a chill minus 179 degrees celsius. Water ice is a solid rock there and CO2 falls as snow. Those buggers better have great winter gear or otherwise, they would look like nothing we know.
There is another explanation. And this one came from deep down in the bowels of Earth.
Before we get into a frenzy now, let’s take two steps back.
There are two sources of methane on Earth.
The one we can see (and smell) every day is biotic methane. This is methane that is the result of biological processes that we know all too well.
- Marshes and other wetlands
- Rice cultivation
- Belching from cows
- Humans passing gas
- and many other sources.
This methane would not exist without life. It produced by methanophile microbes.
But there is another methane world. Far below our feet lies the vast realms of abiotic methane.
This methane is produced deep in the bowels of the planet in sedimentary formations. It is produced but also partly consumed within the bedrock by anaerobic as well as aerobic processes. The pool of abiotic methane extends down deep into the mantle of Earth. It is so massive, it dwarfs all other chemical energy sources by more than an order of magnitude.
Some sources of unconventional gas have built up from this source. They include shale but also the massive deposits of methane clathrates – or methane hydrates – some rave about.
Abiotic methane is formed by chemical reactions that don’t involve organic matter.
This explains where the sometimes massive stores of methane come from on other planets and moons. No life is necessary for that to work. Quite a disappointment for the Mars researchers.
Yet, this methane could be the key to the formation of life on Earth.
This primordial methane rose into the atmosphere where it mixed with nitrogen. Add sunlight to it and an orange haze is produced. This orange haze consists of aerosols and CO2. They are also laden with other organic molecules resulting from those very same reactions.
On top of that, submarine vents added into the picture.
About 15 years ago, researchers at Penn State had found that a set of primitive microbes living in anaerobic conditions. They were close to those submarine vents. They took the carbon dioxide and transformed it into methane and to a substance that’s like vinegar. That’s an organic molecule that plays an important role on the origin of life. The seasoning to the salad of the ingredients so to say.
So aerosols spread over the planet to react with what those submarine vents cooked up. Quite a potent soup and we know the result.
Is this certain knowledge? Nothing is certain when it comes to the origin of life. But it’s one of the most promising pathways that not only would explain how it all came together. It also corresponds to similar processes as they are observed on other heavenly bodies of the Solar System like Titan.
Strong clues here.
Let’s summarize. Geological abiotic processes produce methane that escapes into the primitive atmosphere. This methane reacts with nitrogen under sunlight forming aerosols containing complex organic molecules. Those molecules spread over the planet and help with creating first primitive organic soup. And this gives rise to archaea (a primitive bacteria).
The chemical engine converting CO2 to methane and vinegar assures carbon fixation. Hence, primitive energy conversion freeing first life from external energy sources by happenstance. Such as lightning for example.
And off we go on a journey of billions of years of evolution. Life culminates into coddled, spoilt, self-important snowflakes. Snowflakes that are afraid of the very processes that created them.
All those processes have been active since the planet exists. And they are still active in and on Earth today. Some of them long before life emerged. Without them, we would not exist.
Those methane stores we bring to the surface as Natural Gas have an origin that’s very different from coal and oil. The latter two are the result of the decomposition of organic material deep in Earth. Add in some temperature, pressure and the effects of time.
Methane, on the other hand, is a pure product of Earth. It’s not a chemical cocktail that oil is. Or transformed wood that coal is.
The planet cycles methane as its produced, partly released into the atmosphere and then reacts there into CO2 and water.
The resulting water has created our oceans. The CO2 enters the phytoplankton where it’s used to create sugars and oxygen.
This means that methane is renewable. The planet produces it all the time and its byproducts, mainly CO2 and water are elements in the circle of life. Its a closed loop. In part, its independence from outside influences like sunshine. Abiotic methane is not stored sun energy as oil and coal are. That’s real sustainability, that’s with nature instead of against nature.
That’s true environmentalism as the processes Earth uses all the time are hacked and used for our benefit. And the byproducts go back to nature which replenishes the stocks.
If we consider solar and wind renewables, then all methane must be considered renewable even more.
Methane is a natural part of this world. This planet is a methane making machine since before life exists. Figthing methane and CO2 means figthing life.