Could forms of life exist elsewhere in the universe? To answer this question, extraordinary space missions have been launched in recent years: the satellites Corot and Kepler to detect exoplanets, the rover Curiosity that is trying to find out if the environment on Mars might have been favorable for the appearance of life. But while we’re looking to see if life can exist elsewhere, do we even know how it appeared on Earth? New studies show that the building blocks necessary for the emergence of life on our planet could have been made in Space.
Tonight, November 19th, for the next “Space Tuesday” organized by France’s National Center for Space Studies (CNES), Michel Viso, head of their exobiology program, will lead a discussion on the formation of the first signs of life in the universe. He will be joined by three researchers in exobiology.
Life on Earth could have been brought by comets or meteorites.
Source: Wikipedia Commons
At the end of the 19th century, the theory of panspermy put forth that life on Earth, in the form of microorganisms, could have been brought by meteorites or comets. The hypothesis has its inconsistencies, but it fueled a line of scientific thought.
The most prominent theory regarding the process leading to the appearance of the fundamental molecules of life attributes the role of elementary building blocks to amino acids. In 1920, the biochemist Alexandr Oparin proposed the theory that the Earth’s atmosphere originally had very little oxygen and was favorable to the formation of amino acids. In 1952, Stanley Miller conceived of and carried out an experiment using conditions similar to those put forth by Alexandr Oparin. Thanks to simple chemical reactions at work, he obtained 11 different types of amino acid.
Preuve était faite que / It was clear that the initial spark of life could have appeared relatively easily on Earth. Furthermore, exobiology has shown that the most basic bricks of life also form in the cosmos, especially around stars, in nebulae. Amino acids are found in meteorites and interplanetary dust. A meteorite discovered in 1969 was revealed to contain tens of thousands of organic molecules.
Two recent studies have also advanced the hypothesis that molecules of life could be created and delivered by comets. In the first study, artificially reconstituting a comet yielded the formation of amino acids. The second simulated the conditions of a collision between a comet and the Earth and showed that the impact led to chemical reactions capable of producing amino acids.
An increasing amount of research shows that space can be the source of the organic raw materials at the origin of life. It remains to be seen whether these extraterrestrial molecules played a role in the emergence of life on Earth. “These molecules are present in space and can also form on Earth. So, the answer to this question is very difficult,” explains Michel Viso. They could also have formed on Mars. The mission of the Mars rover Curiosity is to select, collect and analyze samples of the surface to reveal the conditions that reigned here several billion years ago and, potentially, to discover if they could have led to the formation of these famous amino acids.
Three post-doc researchers will also present their latest finding tonight and discuss the implications.
Chemist Caroline Freissinet, analyses the data from one of the instruments on NASA’s Martian robot. She is currently a post doc at the the Goddard Space Flight Center in the US. “These organic molecules could have been preserved in the conditions on Mars,” she writes in her thesis.
Vassilissa Vinogradoff, also a chemist, is trying to determine how amino acids can form in the interstellar environment by recreating these conditions in small chemical reactors in the lab for the Physics of Ionic and Molecular Interactions (PIIM) in Marseille and the Interuniversity Laboratory for Atmospheric Systems (LISA).
Astrophysicist Cécile Favre, currently a post doc at the University of Michigan, uses radioastronomy to understand the chemical and physical processes at work in the regions where stars are born.
To discover the latest advances in exobiology, join the CNES, the Bar des Sciences and MyScienceWork, tonight, November 19, at the Café du Pont-Neuf (Paris) at 19h30. You can also follow the event with the hashtag #CNESTweetup.