Scientists have scoured the universe’s pantry to write what has been described as a “cookbook” containing hundreds of chemical “recipes” capable of creating life. Life, as far as we know, has only evolved once in the universe – on Earth. But the specific chemical reactions that lead to the formation of organisms on our home planet – with our DNA, fatty acids, bills and taxes – may not be the same as those that form organisms in other parts of the world. However, the types of ingredients that can lead to life are not limitless. According to astrobiologists (scientists who study the possibility of life outside Earth), what is needed most is repetitive chemical processes.
“The origin of life is really a process from nothing,” said Betül Kaçar, a NASA-supported astrobiologist and professor of bacteriology at the University of Wisconsin-Madison. “But something can’t happen just once. Life originates from chemistry and conditions that can create a self-replicating reaction pattern.
Kaçar is the lead author of a paper published in the Journal of the American Chemical Society, synthesizing 270 molecular combinations involving atoms from every group and series of the periodic table with stable autocatalytic capabilities. stable and thus promote the evolution of life. Autocatalytic reactions require that the output of the chemical reaction also be a new input, creating a kind of chemical feedback loop.
“We think this type of reaction is very rare,” Kaçar explains. “We show that this is actually not rare. Just look in the right place. » The team hopes their recipe book can help astronomers find the ingredients that create the chemical signature of life on other worlds. Last week, scientists reported in a preprint paper that the James Webb Space Telescope may have found signs of extraterrestrial life on an ocean-covered world 50 miles away. light year. Exoplanet K2-18b is thought to have an atmosphere rich in hydrogen, methane, carbon dioxide and low levels of ammonia and dimethyl sulfide – known to science only as a byproduct of microbial life on Earth. But until living organisms are found for sure elsewhere, the only life we know has evolved here on Earth.
But until living organisms are found for sure elsewhere, the only life we know has evolved here on Earth. “We will never know for sure what happened on this planet to create life. We don’t have a time machine,” Kaçar said. “In vitro, however, we can create a variety of planetary conditions to understand how the dynamics needed to sustain life could have evolved in the first place.” Kaçar’s consortium, supported by NASA and called Metals Use & Selection Through the Ages (MUSE), will focus on reactions involving the elements molybdenum and iron. “Carl Sagan said that if you want to make a cake from scratch, you must first create the universe,” Kaçar said. “I think if we want to understand the universe, we need to bake some pies first.”
source: https://pubs.acs.org/doi/10.1021/jacs.3c07041