The Many Worlds Interpretation of quantum physics has been around for nearly 60 years. It’s a highly controversial idea which suggests that our world — and everything in it — is constantly splitting into alternative timelines. If it’s correct, here’s what your true existence might actually be like.
Over a hundred years ago, the discovery of quantum physics ruined the party. Our comfortable, clockwork conception of universe was thrown into disarray with the realization that, at the micro-scale, there’s some crazy funky stuff going on.
Thanks to quantum mechanics, we now know that matter takes on the properties of both particles and waves. What’s more, thanks to Werner Heisenberg and Erwin Schrödinger, we can never be certain about a particle’s momentum and position, nor can we be certain about an object’s state when it’s not being observed. In other words, the universe — at least at a certain scale — appears to be completely fuzzy and nebulous. Possibly even random.
Quantum physics has royally messed up classical — and seemingly intuitive — principles of space and time, causality, and the conservation of energy. This means that Newtonian, and even Einsteinian, interpretations of the universe are insufficient. Indeed, if we’re to develop a unified and comprehensible theory of everything, we’re going to have to reconcile all of this somehow.
But some physicists, upset by the implications of quantum mechanics on our ultimate understanding of the universe and our place within it, still choose to ignore or dismiss it as a kind of messy inconvenience. And it’s hard to blame them. Quantum physics doesn’t just upset conventional physics. It also perturbs our sense of our place in the universe; it’s Copernican in scale — a paradigm changer the carries deep metaphysical and existential baggage.
Denial, however, won’t help the situation — nor will it further science. Physicists have no choice but to posit theories that try to explain the things they see in the lab, no matter how strange. And in the world of quantum mechanics, this has given rise to a number of different interpretations, including the Copenhagen Interpretation, the Ensemble Interpretation, the de Broglie-Bohm theory, and many, many others.
And of course, there’s the infamous Many Worlds Interpretation.
The “Relative State” Formulation
Back in the 1950s, a Princeton undergraduate by the name of Hugh Everett III embroiled himself in the wonderful and wacky world of quantum physics. He became familiar with the ideas of Niels Bohr, Heisenberg, and Schrödinger, and studied under Robert Dickie and Eugene Wigner. Then, in 1955, he began to write his Ph.D. thesis under the tutelage of John Archibald Wheeler.
In 1957, he published his paper under the name, “Quantum Mechanics by the Method of the Universal Wave Function.” Eventually, after further edits and trimming, it was re-published under the name, “Wave Mechanics Without Probability.” And though he referred to his theory as the “relative state formulation,” it was rebranded as the Many Worlds Interpretation (MWI) by Bryce Seligman in the 60s and 70s.
But like so many seminal theories in science, Everett’s idea was scorned. So scorned, in fact, that he gave up physics and went to work as a defense analyst and consultant.
Now, some 60 years later, his radical idea lives on among a small — but growing — subset of physicists. In a recent poll of quantum physicists, some 18% of respondents said they subscribe to the MWI(as compared to the 42% who buy into the dominant Copenhagen Interpretation).
The Everett Postulate
Essentially, Everett’s big idea was the suggestion that the entire universe is quantum mechanical in nature — and not just the spooky phenomenon found at the indeterministic microscopic scale. By bringing macroscale events into the picture, he upset the half-century’s worth of work that preceded him. The two different worlds, argued Everett, can and must be linked.
No doubt, the problem that quantum mechanics presents is the realization that we appear to live in a deterministic world (i.e. a rational, comprehensible world) that contains some non-deterministic elements. Everett worked to reconcile the micro with the macro by making the case that no arbitrary division needs to be invoked to delineate the two realms.
He considered the universal wavefunction — a mathematical list of every single configuration of a quantum object, like a hydrogen atom. It’s a description of every possible configuration of every single elementary particle in the universe (that’s a big list). What Everett did was apply Schrodinger’s wavefunction equation to theentire universe — which is now known as the Everett Postulate:
All isolated systems evolve according to the Schrodinger equation.
Everett also argued that the measurement of a quantum object doesn’t force it into one comprehensible state or another. Instead, it causes the universe to split, or branch off, for each possible outcome of the measurement; the universe literally splits into distinct worlds to accommodate every single possible outcome. And interestingly, Everett’s idea allows for randomness to be removed from quantum theory, and by consequence, all of physics (thus making physicists very happy).
It’s worth noting that the MWI stands in sharp contrast to the popular Copenhagen Interpretation, a branch of physics which says quantum mechanics cannot produce a coherent description of objective reality. Instead, we can only deal with probabilities of observing or measuring various aspects of energy quanta — entities that don’t conform to classical ideas of particles and waves. It’s proponents talk about the wavefunction collapse — which happens when a measurement is made, and which causes the set of probabilities to immediately and randomly assume only one of the possible values.
So Many Worlds
According to Everett, a “world” is a complex, causally connected sub-system that doesn’t significantly interfere with other elements of the grander superposition. These “worlds” can be called “universes,” but “universe” tends to describe the whole kit-and-kaboodle.
Needless to say, it’s a metaphysical theory that dramatically alters our understanding of the universe and our place in it. If true, the universe is comprised of an ever-evolving series of timelines that branch off to accommodate all possibilities. Subsequently, it means that a version of you — or what you think is you — is constantly branching off into other alternate histories.
For example, in the case of Schrödinger’s cat, it’s not both alive and dead when not observed. Instead, a version of it ceases to exist, while another lives on in an alternative timeline. As another example, one version of you will stop reading my article at this exact point, while another version will continue to the very end. There may even be an evil version of you somewhere. So long as it’s probable — and that it doesn’t violate physical laws at the macro-scale — a new version of the universe, and all that’s within it — will be created. In turn, those will continue to branch off based on the new contingencies contained therein. But Everett-worlds in which probability breaks down can never be realized, and by consequence, never observed.
So what appears to be a single individual living from moment to moment is actually a perpetually multiplying flow of experiences; there is not just one timeline. Instead, there are many, many worlds. This means that all possible alternative histories and futures are real.
This also means that there could be an infinite number of universes — and that everything that could have possibly happened in our past has in fact happened in the past of some other worlds.
Weird and Untestable
Not surprisingly, there are a number of objections to the MWI. As noted, 82% of quantum physicists don’t buy it.
One of the most common complaints is that MWI grossly violates conservation of energy (i.e. where the hell is all the energy coming from to fuel all these new universes?). Others argue that it violates Occam’s Razor, that it doesn’t account for non-local events (like an alien making an observation far, far away), or that its parameters and definitions, like “measurement,” are far too liberal or vague.
And of course, it leads to a host of strange conclusions. For example, a version of you will win the lottery every time you play it. Sure, it’s highly improbable, but not impossible. In the space of all probable worlds, a version of you will have to experience it.
Perhaps even more bizarre is the scenario in which a person — someone who cannot play a musical instrument — sits in front of a piano and plays Debussy’s Claire de Lune to perfection strictly by chance. Sure, the odds of correctly hitting each successive note gets astronomical in scale as the piece progresses — but this is the weirdness that arises when we have to consider (1) probabilities and not impossibilities, and (2) the near-infinite number of expressions of all possible worlds.
But something about this scenario just feels…wrong.
Another interesting and related perspective comes from the Rational Skepticism website:
[F]or now, the MWI is physically dependent. That is, the likelihood of an outcome is assessed from physical potential. However, we all know that the likelihood of events isn’t contingent upon physical potentials. I know, for instance, given the evolution of my own life/mind, that the likelihood of me becoming a materialist tomorrow, is zero. I have no doubt about that, given that I’ve already been there and seen the flaws thereof (not to mention everything else I’ve ‘seen’). Likewise, you all may be sure of some thing or other. Further, for example, though the physical potential exists, the likelihood of tomorrow’s papers headlining The Pope as a murderous gay atheist, seems bleak, to say the least. Therefore, are these many worlds constrained by what is physically possible, or by what is sensibly possible? That is, do mental/emotive concerns dictate what worlds are possible, or simply physical potentials? On the face of it, it would seem that the MWI doesn’t have any recourse towards mental potential/agency.
Which is a great point. At what point does probability — even within the confines of classical physics — enter into the realm of sheer improbability? In the previous example, that of our insanely lucky piano player, such a thing might never play out because the person hasn’t developed the proper finger musculature, or they may suddenly stop mid-performance, aghast at their freakish achievement.
And there’s also the issue of testability. Regrettably, we can’t communicate with our splitting selves. Each version of us can only observe one instance of the universe at any given time. Subsequently, the MWI is considered untestable — leading many to dismiss it as being unscientific or just plain bonkers.
Actually, there may be a way to test it. MWI implies the quantum immortality hypothesis — the argument that a version of us will always observe the universe — even in the most improbable of circumstances. To test the MWI, all one needs to do is attempt suicide based on a 50/50 probability schema. According to the theory, a version of you will survive 50 successive 50/50 suicide attempts — but it’s a one in quadrillion chance. The trick, of course, is to live the life of that particular version of you. Good luck.
Hugh Everett, despite his belief in quantum immortality, died in 1982.
Astronomers have found the first-ever snow line seen around a distant star system using the newAtacama Large Millimeter/submillimeter Array (ALMA) telescope. This llandmark is thought to play an essential role in the formation and chemical make-up of planets around a young star.
ALMA spotted a never-before-seen CO snow line around TW Hydrae, a young star 175 light-years away from Earth. Astronomers believe this nascent solar system has many of the same characteristics that our own Solar System had when it was just a few million years old. The results were published in Science Express.
“ALMA has given us the first real picture of a snow line around a young star, which is extremely exciting because of what it tells us about the very early period in the history of our own Solar System,” said Chunhua “Charlie” Qi, a researcher with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., who led the international research team with Karin Oberg, a researcher with Harvard University and the University of Virginia in Charlottesville.
“We can now see previously hidden details about the frozen outer reaches of another solar system, one that has much in common with our own when it was less than 10 million years old,” said Qi.
Snow lines have, until now, only been detected by their spectral signatures; they have never been imaged directly, so their precise location and extent could not be determined.
This is because snow lines form exclusively in the relatively narrow central plane of a protoplanetary disk. Above and below this region, stellar radiation keeps the gases warm, preventing them from forming ice. Only with the insulating effect of the concentrated dust and gas in the central plane of the disk can temperatures drop sufficiently for CO and other gases to cool and freeze.
Normally, this outer cocoon of hot gas would prevent astronomers from peering inside the disk where the gas had frozen out. “It would be like trying to find a small, sunny patch hidden within a dense fogbank,” said Oberg.
The astronomers were able to pierce the intervening CO fog by instead hunting for a different molecule known as diazenylium (N2H+). This fragile molecule is easily destroyed in the presence of CO gas, so would only appear in detectable amounts in regions where CO had frozen out, and is hence a proxy for CO ice.
Diazenylium shines brightly in the millimeter portion of the spectrum, which can be detected by radio telescope like ALMA here on Earth.
ALMA’s unique sensitivity and resolution allowed the astronomers to trace the presence and distribution of diazenylium, finding a clearly defined boundary approximately 30 astronomical units (AU) from TW Hydrae (one AU is the Sun-Earth distance).
“Using this technique, we were able to create, in effect, a photonegative of the CO snow in the disk surrounding TW Hydrae,” said Oberg. “With this we could see the CO snow line precisely where theory predicts it should be — the inner rim of the diazenylium ring.”
Snow lines, astronomers believe, serve a vital role in the formation of a solar system. They help dust grains overcome their normal tendency to collide and self-destruct by giving the grains a stickier outer coating. They also increase the amount of solids available and may dramatically speed up the planet formation process. Since there are multiple snow lines, each may be linked to the formation of specific kinds of planets.
Around a Sun-like star, the water snow line would correspond approximately to the orbit of Jupiter and the CO snow line would roughly correspond to the orbit of Neptune. The transition to CO ice could also mark the starting point where smaller icy bodies like comets and dwarf planets like Pluto would form.
Oberg also points out that the CO snow line is particularly interesting since CO ice is needed to form methanol, which is a building block of more complex organic molecules that are essential for life. Comets and asteroids could then ferry these molecules to newly forming Earth-like planets, seeding them with the ingredients for life.
These observations were made with only a portion of ALMA’s eventual full complement of 66 antennas. The researchers hope future observations with the full array will reveal other snow lines and provide additional insights into the formation and evolution of planets.
During an epoch of dramatic climate change 200,000 years ago, Homo sapiens (modern humans) evolved in Africa. Several leading scientists are asking: Is the human species entering a new evolutionary, post-biological inflection point? Paul Davies, a British-born theoretical physicist, cosmologist, astrobiologist and Director of the Beyond Center for Fundamental Concepts in Science and Co-Director of the Cosmology Initiative at Arizona State University, says that any aliens exploring the universe will be AI-empowered machines. Not only are machines better able to endure extended exposure to the conditions of space, but they have the potential to develop intelligence far beyond the capacity of the human brain.
“If we build a machine with the intellectual capability of one human, then within 5 years, its successor is more intelligent than all humanity combined,” says Seth Shostak, SETI chief astronomer. “Once any society invents the technology that could put them in touch with the cosmos, they are at most only a few hundred years away from changing their own paradigm of sentience to artificial intelligence,” he says.
ET machines would be infinitely more intelligent and durable than the biological intelligence that created them. Intelligent machines would be immortal, and would not need to exist in the carbon-friendly “Goldilocks Zones” current SETI searches focus on. An AI could self-direct its own evolution, each “upgrade” would be created with the sum total of its predecessor’s knowledge preloaded.
“I think we could spend at least a few percent of our time… looking in the directions that are maybe not the most attractive in terms of biological intelligence but maybe where sentient machines are hanging out.” Shostak thinks SETI ought to consider expanding its search to the energy- and matter-rich neighborhoods of hot stars, black holes and neutron stars.
Before the year 2020, scientists are expected to launch intelligent space robots that will venture out to explore the universe for us.
“Robotic exploration probably will always be the trail blazer for human exploration of far space,” says Wolfgang Fink, physicist and researcher at Caltech. “We haven’t yet landed a human being on Mars but we have a robot there now. In that sense, it’s much easier to send a robotic explorer. When you can take the human out of the loop, that is becoming very exciting.”
“Consider the human brain,” says the physicist Sir Roger Penrose. “If you look at the entire physical cosmos, our brains are a tiny, tiny part of it. But they’re the most perfectly organized part. Compared to the complexity of a brain, a galaxy is just an inert lump.”
It concludes that the size of our frontal lobes — an area in the brain of mammals located at the front of each cerebral hemisphere — cannot solely account for humans’ superior cognitive abilities.
The study also suggest that supposedly more “primitive” areas, such as the cerebellum, were equally important in the expansion of the human brain. These areas may therefore play unexpectedly important roles in human cognition and its disorders, such as autism and dyslexia, say the researchers.
The Durham and Reading researchers, funded by The Leverhulme Trust, analyzed data sets from previous animal and human studies using phylogenetic (“evolutionary family tree”) methods, and found consistent results across all their data. They used a new method to look at the speed with which evolutionary change occurred, concluding that the frontal lobes did not evolve especially fast along the human lineage after it split from the chimpanzee lineage.
Human brains share a consistent genetic blueprint and possess enormous biochemical complexity. The same basic functional elements are used throughout the cortex and understanding how one area works in detail will uncover fundamentals that apply to the other areas as well, according to an earlier study completed by scientists at the Allen Institute for Brain Science.
Human brains share a consistent genetic blueprint, and possess enormous biochemical complexity, they said, based on the first deep and large-scale analysis of the vast data set publicly available in the Allen Human Brain Atlas. Among other findings, these data show that 84% of all genes are expressed somewhere in the human brain and in patterns that are substantially similar from one brain to the next.