By the end of this century, says astrophysicist Martin Rees, we should be able to ask whether or not we live in a multiverse, and how much variety of the laws of physics its constituent ‘universes’ display. The answer to this question, says Rees, “will determine how we should interpret the ‘biofriendly’ universe in which we live (sharing it with any aliens with whom we might one day make contact).”
The same fundamental laws of physics apply throughout the entire domain we can survey with telescopes. Were that not so—were atoms ‘anarchic’ in their behavior—we’d have made no progress in understanding the observable universe. But this observable domain, says Rees, may not be all of physical reality; some cosmologists speculate that ‘our’ big bang wasn’t the only one—that physical reality is grand enough to encompass an entire ‘multiverse’.
Even conservative astronomers, concludes Rees, “are confident that the volume of space-time within range of our telescopes—what astronomers have traditionally called ‘the universe’—is only a tiny fraction of the aftermath of the big bang. We’d expect far more galaxies located beyond the horizon, unobservable, each of which (along with any intelligences it hosts) will evolve rather like our own.”
Following the laws of physics, Charles Cockell suggests that life on Earth might be a template for life in the universe, adhering to a standard model of constants or equations of life. Cockell, an astrobiologist at the University of Edinburgh and Director of the UK Center for Astrobiology and author of The Equations of Life: How Physics Shapes Evolution, views the topic of life’s construction through the lens of an observer who is trying to understand how life on Earth can serve as a test case for possible life elsewhere in the universe.
No matter how different the conditions on distant worlds, all presumably have the same laws of physics — from quantum mechanics to thermodynamics and the laws of gravity reports the New York Times. And life, as Cockell puts it, is simply living matter, “material capable of reproducing and evolving.” If there is biology elsewhere in the universe, we would find it strikingly familiar not only in appearance but down to the carbon-based machinery in its cells.
There are equations and rules that are not limited to living systems that underlie the way that life operates. These equations are consistent, so far as we can tell, anywhere in the universe. To understand what life might look like elsewhere, it is critical that we have a thorough understanding of how it works here.
Rerun the tape of evolution, and DNA, RNA, ATP, the Krebs cycle — the rigmarole of Biology 101 — would probably arise again, here or in distant worlds, writes George Johnson in the New York Times: Single cells would then join together, seeking the advantages of metazoan life, until before you know it something like the earthly menagerie would come to be.
The laws of biology mimic the physical laws are the same everyplace –gravity, for instance, is omnipresent, not exclusive to our solar system. Restrictions are everyplace –organic molecules, on Earth or elsewhere, still disintegrate at high temperatures, deactivate at low ones. Certain ingredients, most everyplace, are indispensable for life –carbon is the optimal element to assemble burgeoning life; water is the ideal solvent to shuttle it.
We consider “life as we know it” as being the breathing of oxygen and the ability to walk under blue skies. While there are likely many worlds out there much like our own, conditions elsewhere in the universe can easily be very different. Yet so long as the equations work out right, life may well have an infinite number of variations – each different – yet each similar due to the equations that underlie the physical universe.
“The laws of physics channel living creatures into restricted shapes,” he says. “They narrow the scope of evolution. Alien life may have many similarities to life here.”
“Go into the ocean,” Cockell says. There, “creatures with slim, streamlined bodies” predominate, and for obvious reasons—“to move fast through the water.” That has been true for hundreds of millions of years, of course; dolphins, sharks, the ichthyosaurus—mammal, fish, and extinct dinosaur—all have a reasonably comparable appearance. “Things end up looking the same, even though they are completely different lineages,” says Cockell.
On land, most animals have appendages, limbs for moving about; in the sky, whether pterodactyls or pigeons, “laws that govern aerodynamics are observed.” Even butterflies, albeit exquisitely detailed —“endless colors, hues, and patterns”—follow the equation. “Too small a wing, and a butterfly can’t lift off,” Cockell says. Details, he concedes, can be “endless”—but “physics restricts the form.”
Atoms combine to form ever more complex structures that comprise living systems that are designed to capture energy from the environment and create copies of itself to continue to do so over the course of life’s history on our planet – adapting to changes in the environment all the while.
The Daily Galaxy via NASA Astrobiology, New York Times, and Rees, Martin. On the Future (p. 186)
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