Alien Life May Not Even Look Like Life
At an incredibly basic level, we look for life elsewhere in the universe by looking for ourselves. “Ourselves” here is not exclusive to humans. Rather, it refers to all forms of Earthlings. When we look to the stars—and to the numerous planets orbiting those stars—trying to spot signs of life, we’re looking not for any life at all, but for life as we know it.
In some ways, we kind of have to. It’s hard enough to look for things we know are signs of life—seeing chemical signals from other worlds is no easy task. So, we look for signals of the only kind of life that we know for certain exists—carbon-based, otherwise known as organic.
But the thing is, we have no guarantee that Earth’s version of life is the only one that can work. And a recent study has re-emphasized that we may in fact be limiting our chances at finding alien life by focusing our search on the most familiar signs.
That being said, even the team behind this paper started with life as we know it before branching out. The study focused on what’s called autocatalysis—a chemical interaction that can sustain itself. Basically, the molecules present in the reaction produce more molecules also capable of maintaining that reaction, which produce even more molecules, and so on. The reaction keeps itself going.
It’s key to life on Earth. In fact, one could say that it is the thing that keeps all life on Earth going. “One of the major reasons that origin-of-life researchers care about autocatalysis is because reproduction—a key feature of life—is an example of autocatalysis,” Betül Kaçar, one of the authors on the study, said in a Space.com article. “Life catalyzes the formation of more life. One cell produces two cells, which can become four and so on. As the number of cells multiply, the number and diversity of possible interactions multiplies accordingly.”
It is not, however, a life-exclusive phenomenon. Autocatalysis doesn’t need to involve organic compounds. And it has actually long been thought that autocatalytic reactions could play a substantial role in creating life where there formerly was none.
Problematically, though, we haven’t had very many examples of non-organic autocatalysis available to us in the past. And the infrequent appearance of these reactions has long been taken to mean that they’re pretty improbable, meaning that there’s a low chance that they would generate life on another world.
But the team wanted to challenge this idea. And so, they dug into the backlogs of science. Using modern searching and translation tools, the team was able to comb through two centuries of scientific records and conduct a fairly comprehensive survey of documented of autocatalytic reactions.
In the end, they found 270 of these self-sustaining cycles. And not only were some of them non-organic—most of them were not carbon-based. Some centered on rare or radioactive elements. Some would only occur under extreme temperature or pressure conditions. And four of them even involved noble gasses, which are notorious for reacting with almost nothing.
Guess these reactions aren’t so rare after all, huh?
Moving forward, the team hopes that their new library of autocatalytic reactions will be used in experiments that could directly probe the kinds of effects that these cycles can have on chemistry—especially considering that they can be combined to make more and more complex reactions and products.
“The cycles presented here are an array of basic recipes that can be mixed and matched in ways that haven't been tried before on our planethttps://www.popularmechanics.c...,” one of the study authors, Zhen Peng, told Space.com. “They might lead to the discovery of completely new examples of complex chemistry that work in conditions where carbon- or even silicon-based cycles are too either combusted or frozen out.”
It's far too early to know for sure if this will be the key to finding life on another planet. But considering how new we are to this whole searching-for-extraterrestrial-life thing, it certainly doesn’t hurt to keep an open mind.
