Can life exist out there?” is a question that has reigned over our curious minds on whether extra-terrestrial life can exist – and if it does, how? In the unlimited expanse of the universe, in which trillions and trillions of stellar systems are thriving with their respective planetary systems, just like our own Solar System, one can simply guess the chances of life – not necessarily human-like – proliferating “out there”.
Riding on this optimism of life being “out there”, a team of scientists led by researchers from the University of Wisconsin–Madison (UW-M), are writing a “cookbook” of various possible chemical recipes that have the potential to give rise to life by simulating conditions that could prevail on planets in other stellar systems in lab conditions.
Their bold research is based on the assumption that extra-terrestrial life anywhere in the universe can emanate from only a limited permutation and combination of chemical ingredients. Their mix of ingredients could potentially help in the search for life by focusing on the most likely combination that can work together to give rise to ET life forms in different planetary conditions.
The researchers are basing their research on two important factors – autocatalytic reactions and comproportionation reactions. Autocatalytic reactions are chemical reactions producing molecules that cause the same reactions to recur again and again. Comproportionation reactions involve the combination of two compounds with the same element with different numbers of electrons, which can lead to a new compound with its elements in their starting stages of reactive states.
The UW-M researchers have compiled 270 combinations of molecules that have the potential to sustain autocatalytic reactions, and these include atoms from groups and series across the periodic table, according to the UW-M website.
The comproportionation reactions facilitate the autocatalytic reactions. The former leads to multiple copies of some molecules involved to facilitate the next steps in the autocatalytic reactions. The website describes the autocatalytic reactions by citing the example of a rapidly growing population of rabbits, pairs of which come together to produce litters of new rabbits, who in turn grow up and pair off to make more rabbits. However, as the process goes on, the different permutations and combinations – the inputs – bring in changes in the outputs, marking changes in potential life forms.
“If those conditions are right, you can start with relatively few of those outputs,” the website quotes Zach Adam, UW–Madison geoscientist studying the origins of life on Earth and co-author of the study, published in Journal of the American Chemical Society on September 18. “Every time you take a turn of the cycle you spit out at least one extra output which speeds up the reaction and makes it happen even faster.”
“The origin of life really is a something-from-nothing process,” says Betül Kaçar, an astrobiologist and UW–Madison professor of bacteriology, who leads a NASA-supported consortium, Metal Utilization & Selection Across Eons (MUSE).
“But that something can’t happen just once. Life comes down to chemistry and conditions that can generate a self-reproducing pattern of reactions…We will never definitively know what exactly happened on this planet (Earth) to generate life. We don’t have a time machine. But, in a test tube, we can create multiple planetary conditions to understand how the dynamics to sustain life can evolve in the first place.”