Scientists propose a "missing law" for evolution in the universe
A team of scientists and philosophers is proposing a new law of nature to describe the vast complexity and diversity seen across the universe.
Why it matters: The law could help to explain the emergence of complex systems around us — from the arrangements of stars into galaxies to the complex chemistries of atmospheres on planets to the countless forms of life and more — and predict how others, like AI, might change over time.
The big picture: We experience the world at the mercy of time. Governed by the second law of thermodynamics, there are irreversible processes — eggs crack, ice melts, life ends.
- But at the same time, flowers bloom and babies are born. Complex systems arise and they become more complex over time.
- "In a deep sense, there are two time arrows that we experience in life," says Robert Hazen of the Carnegie Institution for Science and who is a co-author of a paper published this week in PNAS describing the proposed law. "One is the idea of aging and death and the other is the idea of renewal and organization," he says.
- For decades, scientists have tried to figure out how to reconcile the two.
- "The second law must be obeyed by all systems, but there's still something missing that needs to be articulated to effectively describe all the richness that we see in our everyday lives and also across the cosmos," says Michael Wong, an astrobiologist and planetary scientist at the Carnegie Institution and co-author of the paper.
What's new: The "Law of Increasing Functional Information" described in the paper by Wong, Hazen and their collaborators proposes to explain how that complexity arises.
- Biological systems — plants, animals and other living organisms — evolve by developing traits that increase their chances of surviving and reproducing.
- A central idea of this selection is fitness — the capacity of something to get to exist for some time because it performs a useful function.
- The new law suggests selection isn't just happening in living systems.
Details: Atoms and molecules interact to form many configurations of non-living systems, including minerals, atmospheres on alien planets and galaxies structured from stars.
- Two elements — hydrogen and helium — forged together in stars after the Big Bang gave rise to the nearly 120 elements in the universe today.
- The proposed law states that those systems and others will evolve "if many different configurations of [it] undergo selection for one or more functions."
- "You have a universe that keeps mixing things up and then trying out new possibilities," Hazen says, adding that it encompasses biological evolution, too.
- Things that work are selected for, he adds. "That works on nonliving worlds, and it works on living worlds. It's just a natural process that seems to be universal."
What they're saying: "In physics, there is no notion of the fitness of things," says Stuart Kauffman, a theoretical biologist who wasn't involved in the new research. "But it is all over biology."
- The team's notion of fitness beyond biology is "really subtle, complex and wonderful," Kauffman adds.
But, but, but... Some scientists have questioned whether what the researchers are describing clears the bar of a new law, Wong says.
- And, some say evolution is strictly about Darwinian natural selection and common descent, Hazen says.
- But, "I'm talking about diversification and patterning through time" from one stage to the next, he says.
- Biology, minerals, isotopes and atoms all have selection mechanisms, Hazen adds. "That's the commonality [and] it is just the different kinds of selection."
What's next: Hazen and Wong say their law now needs to be put to the test.
- NASA's upcoming Dragonfly mission is designed to sample the surface of Saturn's moon, Titan. By analyzing the chemistry of the moon's atmosphere, the team may find out "if the law of functional information actually applies to describing how this faraway world and the outer solar system evolved as well," Wong says. "That would be really exciting for me."
- Hazen, a mineralogist, wants to study the complexity of minerals over Earth's history and test his hypothesis that the functional information of minerals increases.
- The new law could even inform questions about how AI might evolve, Hazen says. "It's an information system. We need to have laws of information and know how information and evolution are intertwined if we're going to understand what AI is doing and where it's going."