DarkRange55
Where in the world is John Galt? 🥞
- Oct 15, 2023
- 2,234
One idea advanced by theoretical physicist John Archibald Wheeler in a phone call to Richard Feynman in 1940 — Wheeler was famous for proposing off-the-wall ideas in physics that, just maybe, actually described reality. In this case, the postulate he presented to Feynman was the one-electron universe: the idea that all electrons, and their antimatter counterparts the positrons, are actually manifestations of the same single electron. This electron moves forward and backward in time, changing direction. What we perceive as countless electrons and positrons is, in this view, an illusion created by our position in time.
What prompted Wheeler was puzzlement over a basic fact of nature: all electrons have exactly the same charge and mass. One explanation is that all electrons must be identical—but what enforces that rule? Another possibility is more radical: they are not merely identical, but literally the same electron. When this electron moves backward in time, it appears to us as a positron. Wheeler was not alone in thinking along these lines. Ernst Stueckelberg independently explored similar ideas involving zig-zagging world lines to explain how particles and antiparticles annihilate. Taken seriously, this interpretation suggests that antimatter is, in some sense, anti-time.
While most physicists do not believe the one-electron universe is literally true, the idea had a profound influence. It pushed Feynman to think more deeply about antimatter as matter moving backward in time. This line of thought fed directly into his path-integral formulation and a spacetime interpretation of quantum mechanics, work that ultimately earned him the Nobel Prize in Physics in 1965. Not bad for an idea born from a seemingly crazy phone call.
Electrons can be deflected, scattered, or made to wobble by photons, but turning completely around and traveling backward in time is another matter entirely. There is an important caveat here: it is not necessary that electrons actually travel backward in time. Rather, the difference between an electron and a positron—specifically their opposite charges—is physically indistinguishable from what we would observe if one were moving backward in time. Mathematically, the two descriptions are equivalent. Still, if electrons and positrons are truly the same particle, then a positron corresponds to a time-reversed electron.
One thing we do know is that electrons, like everything else, are always moving forward in time. Relativity shows that the rate at which time passes can change. By moving very fast or existing near a black hole, one can effectively travel into the future more quickly—an idea popularized by Interstellar, though the real physics is more complicated.
Some interpretations even suggest that when an electron and a positron annihilate, nothing is actually destroyed. Instead, the electron may simply reverse direction in time. Extending this idea to other forms of antimatter becomes extremely tricky. If energy truly moved backward in time, it would violate entropy, which is why many physicists regard these interpretations as mathematical conveniences rather than literal descriptions of reality.
The most serious problem with the one-electron universe is observational. If it were correct, we should see roughly equal numbers of electrons and positrons in the universe, and we do not. Instead, electrons vastly outnumber positrons. This ties into a deeper mystery: the existence of enormous positron emissions in the Milky Way. Beginning in 1997, observations by the Compton Gamma Ray Observatory revealed intense gamma-ray emissions from the galactic center, extending thousands of light-years, produced by electron-positron annihilation. The sheer number of positrons involved is staggering, yet there is no obvious source. Various explanations have been proposed, including relic positrons from a more active galactic past, neutron stars, unseen black holes, or even interactions involving dark matter. None are fully satisfactory, leaving both the positrons and their origin unexplained.
The one-electron universe was not Wheeler's only unconventional idea. He also asked how something could arise from nothing, as the universe appears to have done. This led him to propose the participatory anthropic principle, based on the notion that information is fundamental to reality. Wheeler summarized this idea as "it from bit," meaning that physical reality ultimately arises from binary yes-or-no questions, much like a computer. In this view, observers are not passive but participate in bringing reality into being.
Wheeler argued that the questions we ask about the universe help determine the answers we obtain. Reality, in this framework, emerges through a sequence of binary choices, narrowing possibilities as observations are made. Consciousness thus seems to play a role in the manifestation of the universe, even acting retrocausally by helping to bring about not just the present, but the past as well. The future, presumably, remains open.
Taken to its extreme, this view implies that consciousness is what makes the universe exist at all—without observers, there would be no universe. While many do not accept this interpretation and believe the universe exists independently of observation, Wheeler's ideas, shared by several other major figures in physics, remain provocative and continue to provide food for thought.
What prompted Wheeler was puzzlement over a basic fact of nature: all electrons have exactly the same charge and mass. One explanation is that all electrons must be identical—but what enforces that rule? Another possibility is more radical: they are not merely identical, but literally the same electron. When this electron moves backward in time, it appears to us as a positron. Wheeler was not alone in thinking along these lines. Ernst Stueckelberg independently explored similar ideas involving zig-zagging world lines to explain how particles and antiparticles annihilate. Taken seriously, this interpretation suggests that antimatter is, in some sense, anti-time.
While most physicists do not believe the one-electron universe is literally true, the idea had a profound influence. It pushed Feynman to think more deeply about antimatter as matter moving backward in time. This line of thought fed directly into his path-integral formulation and a spacetime interpretation of quantum mechanics, work that ultimately earned him the Nobel Prize in Physics in 1965. Not bad for an idea born from a seemingly crazy phone call.
Electrons can be deflected, scattered, or made to wobble by photons, but turning completely around and traveling backward in time is another matter entirely. There is an important caveat here: it is not necessary that electrons actually travel backward in time. Rather, the difference between an electron and a positron—specifically their opposite charges—is physically indistinguishable from what we would observe if one were moving backward in time. Mathematically, the two descriptions are equivalent. Still, if electrons and positrons are truly the same particle, then a positron corresponds to a time-reversed electron.
One thing we do know is that electrons, like everything else, are always moving forward in time. Relativity shows that the rate at which time passes can change. By moving very fast or existing near a black hole, one can effectively travel into the future more quickly—an idea popularized by Interstellar, though the real physics is more complicated.
Some interpretations even suggest that when an electron and a positron annihilate, nothing is actually destroyed. Instead, the electron may simply reverse direction in time. Extending this idea to other forms of antimatter becomes extremely tricky. If energy truly moved backward in time, it would violate entropy, which is why many physicists regard these interpretations as mathematical conveniences rather than literal descriptions of reality.
The most serious problem with the one-electron universe is observational. If it were correct, we should see roughly equal numbers of electrons and positrons in the universe, and we do not. Instead, electrons vastly outnumber positrons. This ties into a deeper mystery: the existence of enormous positron emissions in the Milky Way. Beginning in 1997, observations by the Compton Gamma Ray Observatory revealed intense gamma-ray emissions from the galactic center, extending thousands of light-years, produced by electron-positron annihilation. The sheer number of positrons involved is staggering, yet there is no obvious source. Various explanations have been proposed, including relic positrons from a more active galactic past, neutron stars, unseen black holes, or even interactions involving dark matter. None are fully satisfactory, leaving both the positrons and their origin unexplained.
The one-electron universe was not Wheeler's only unconventional idea. He also asked how something could arise from nothing, as the universe appears to have done. This led him to propose the participatory anthropic principle, based on the notion that information is fundamental to reality. Wheeler summarized this idea as "it from bit," meaning that physical reality ultimately arises from binary yes-or-no questions, much like a computer. In this view, observers are not passive but participate in bringing reality into being.
Wheeler argued that the questions we ask about the universe help determine the answers we obtain. Reality, in this framework, emerges through a sequence of binary choices, narrowing possibilities as observations are made. Consciousness thus seems to play a role in the manifestation of the universe, even acting retrocausally by helping to bring about not just the present, but the past as well. The future, presumably, remains open.
Taken to its extreme, this view implies that consciousness is what makes the universe exist at all—without observers, there would be no universe. While many do not accept this interpretation and believe the universe exists independently of observation, Wheeler's ideas, shared by several other major figures in physics, remain provocative and continue to provide food for thought.
