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The answer to the question of how life came into existence remains a scientific mystery to this day.
While experts agree on prevailing theories, we are yet to fully understand how life on Earth started, and where it came from.
And in an effort to understand as much as possible the origin of life, NASA Astrobiologists turned to their laboratory to answer some of the fundamental questions about life and its origins.
Scientists tell us that some four billion years ago, on a young Earth, life came into existence.
While we still don’t know how exactly that spark of life took place, evidence tells us that it occurred deep beneath Earth’s early oceans, in a place where the Sun’s rays could barely reach it.
If we can understand how that spark formed, and what exactly kickstarted life into existence, it could help us understand how alien life may develop on distant exoplanets and alien moons.
One of the main hypotheses about the origins of life points towards deep-sea structures called hydrothermal vents, which are essentially cracks in the ocean floor associated with volcanic activity. It is there where heat escapes from deep inside the planet.
Billions of years ago, when Earth was young, it was bathed in violent and deadly ultraviolet rays coming from the sun. But life emerged deep beneath the oceans where the sun’s rays could not penetrate. It is believed that around thermal vents, creatures emerged that could survive without photosynthesis, a process that later became vital for most living creatures on Earth.
Down there, deep beneath the oceans, Earth’s first inhabitants relied on chemosynthesis, where organisms harnessed chemical energy as they clustered around thermal vents.
Chemical reactions between hydrogen sulfide emerging from the hydrothermal vents and oxygen present in the seawater around it gave off sugar molecules: food.
Bacteria formed, and other animals that could feed off them and the nutrients they produced managed to survive in isolation and darkness.
This is huge news in our hunt for alien life.
NASA experts are convinced that some of the most distant moons in our solar system lice Europa and Enceladus may contain hydrothermal vents in their liquid oceans beneath their frozen surface.
And to understand these processes better, astrobiologist Laurie Barge and her team crafter small seafloors at their Jet Propulsion Laboratory. There’ they recreated the necessary conditions that existed billions of years ago on Earth.
“Understanding how far you can go with just organics and minerals before you have an actual cell is really important for understanding what types of environments life could emerge from,” Barge explained.
“Also, investigating how things like the atmosphere, the ocean and the minerals in the vents all impact this can help you understand how likely this is to have occurred on another planet.”
NASA researchers created a mixture using water, minerals as well as pyruvate and ammonia – two essential molecules that form under hydrothermal vent conditions, vital for the formation of amino acids.
As noted in the NASA statement, “scientists then tested their hypothesis by heating the solution to 158 degrees Fahrenheit (70 degrees Celsius) — the same temperature found near a hydrothermal vent — and adjusting the pH to mimic the alkaline environment.”
“They also removed the oxygen from the mixture because, unlike today, early Earth had very little oxygen in its ocean. The team additionally used the mineral iron hydroxide, or “green rust,” which was abundant on early Earth.”
Researchers noticed that once they injected small amounts of oxygen into the water, amino acid alanine formed.
This also created alpha hydroxy acid lactate, a byproduct of amino acid reactions that can combine forming complex organic molecules that can help kick start life.
“We’ve shown that in geological conditions similar to early Earth, and maybe to other planets, we can form amino acids and alpha hydroxy acids from a simple reaction under mild conditions that would have existed on the seafloor,” Barge explained.
As explained by NASA, Barge’s creation of amino acids and alpha hydroxy acids in the lab is the culmination of nine years of research into the origins of life