According to MIT researchers, life would have appeared in a small pond. According to the new study, the pond was an environment conducive to the birth of the first forms of life on Earth. The cradle of life would thus be a body of water having a depth of only ten to one hundred centimeters. This situation would have made it capable of containing high concentrations of nitrogen, the main ingredient of life.
“Many scientists believe that the origin of life requires fixed nitrogen, so it is unlikely to come from the ocean,”said Sukrit Ranjan, a researcher at MIT. “It’s a lot more believable than it happens in a pond.”
Lightning as a trigger
If life really resulted from a reaction involving nitrogen, two hypotheses can be advanced. The first is that life was born in the depths of the ocean, where nitrogen oxides could have interacted with carbon dioxide. The latter could have gushed hydrothermal vents to form the first molecules of life.
The second explanation involves RNA or ribonucleic acid. This molecule helps to code the genetic information. In its primitive form, it floated freely. Scientists believe that, in contact with nitrogen oxides, it could have contributed to forming the first molecular chains of life.
This formation process could have occurred in humid places such as oceans, lakes or shallow ponds. Nitrogen oxide would have deposited there after the degradation of the nitrogen in the terrestrial atmosphere. The latter would have been affected by an energy event, probably by lightning.
“Lightning is like a very intense bomb going off,” Ranjan said. “It produces enough energy to break this triple bond in our atmospheric nitrogen gas to produce nitrogen oxides that can then seep into water surfaces . “
There would have been enough lightning to produce nitrogen oxide in abundance to fuel the formation of life. It would have stabilized once entered the oceans. However, it would have been eliminated by ultraviolet light and iron. In this case, it would be impossible for it to be at the origin of the first living organisms.
On the other hand, the shallow ponds would have offered better chances to catalyze the first living organisms. Basins have less volume and the compounds can not be diluted. Consequently, the ponds would have been much more concentrated in nitrogen oxide. In this case, this element would have easily interacted with other molecules such as RNA.
The riddle is not quite resolved yet
According to another group of scientists, this process would have occurred about 3.9 billion years ago, just before the first signs of life on Earth appeared. It took place in an area of 500 square kilometers of ponds and lakes.
“This area is tiny compared to the current lakes. However, it was essential at the beginning of life, it was quite adequate, “ they said.
The question of the origin of life on Earth is not entirely resolved. Nevertheless, Ranjan is convinced that the new study has the merit of providing convincing evidence.