2023-04-26 05:01:25
How does science explain what life is? Micro sciences interviews Blaise Mulhauser, biologist and director of the Neuchâtel Botanical Garden to understand how life appeared on Earth and perhaps also on Mars.
“We estimate that life on Earth appeared 4 billion years ago,” says in Micro sciences Blaise Mulhauser, a biologist passionate about microbialites: pebbles that carry the remains of the first forms of life on Earth. According to him, what particularly interests scientists today is to seek other evidence of life elsewhere, in the universe, on the basis of knowledge acquired on Earth.
How did life on Earth start?
4.5 billion years ago, our planet was formed. But it is far from welcoming: a hot ball, resulting from collisions with everything that walks around the solar system at this time.
It will take time, half a billion years, for the oceans to form. There is no oxygen, the atmosphere is saturated with carbon dioxide and other fumes ejected by volcanic activity.
So how from a smoking pebble, floating in space, do we get life?
According to the director of the Neuchâtel botanical garden, it’s almost a philosophical question and there are several hypotheses to explain life on Earth.
Science to explain life
In the 1950s, scientists were able to prove the emergence of life by large electro-chemical reactions.
Microbial structures called microbialites. [Jean-Louis Menou – AFP]A fundamental experiment, called “primitive soup”, made it possible to understand that the presence of water, electricity, meteorological phenomena (lightning and lightning) and a high temperature in water allowed molecules to assemble through these chemical reactions.
The first footprints of life
The oldest traces of life activity on earth, discovered in stones, date back 3.480 billion years, according to the scientific community, says Blaise Mulhauser.
The first stigmata of life are materialized by imprints of an activity marking the stone by mineralogical traces, such as deposits of iron, sulfur or carbon, the basic element of life.
A great mystery
Since no one witnessed its beginnings, how do we know that life began 4.5 billion years ago? This is mainly due to scientific knowledge in relation to the history of the Earth, the atmosphere, the environment and the presence of the other explains the biologist.
This appearance of life on earth still has many gray areas.
We can’t help but tell ourselves that if life appeared on our planet in fairly spartan conditions, it could also have appeared elsewhere… on planets just as hostile as ours: Mars, for example! And that’s the whole point of the exoMars mission, which will go in search of other potential traces of life… in 2028. (See box)
Life is still a great abstraction, isn’t it?
>> Listen to the podcast:
A special episode produced as part of the exhibition “Traces of life: Earth! Mars?” to discover until December 3, 2022, at the Neuchâtel botanical garden.
>> For more information: https://www.jbneuchatel.ch/
Texte web : Andreia Glanville
Journalist: Huma Khamis
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