The evidence is stacking up that the Many Worlds hypothesis could be correct. ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏
October 21, 2026—Do we live in a multiverse? Plus, a super typhoon in the Philippine Sea sets a record, and the Orionids meteor shower is peaking.
—Andrea Gawrylewski,
Chief Newsletter Editor
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Typhoon Champi. Himawari-9/CIRA/NOAA
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Super Typhoon Champi in the Philippine Sea reached wind speeds of about 185 miles per hour (around 290 kilometers per hour) yesterday afternoon, setting the record for the strongest storm of the year. | 2 min read
The Orionids meteor shower is peaking this week (tonight especially). Here's how to see it. | 2 min read
For the first time, physicists managed to trap a single subatomic particle of antimatter for months at a time in a way that allows them to study its quantum states. | 3 min read
The actress Christina Applegate revealed on social media yesterday that her multiple sclerosis diagnosis in 2021 was incorrect. While not the norm, this type of misdiagnosis is far from unusual, experts say. | 2 min read
Besides building crewed outposts at the lunar south pole, where else should astronauts go on the moon? An authoritative new report has suggestions for the most exciting potential human landing sites. | 6 min read
Tom Stalcup, the Republican Party’s candidate to represent Massachusetts’s fourth district in Congress, holds a Ph.D. in physics. Scientific American spoke to him about climate change, misinformation and health care. | 7 min read
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Many Worlds
Quantum mechanics is one of the most successful theories in physics—it can, for example, make mathematical predictions that are astonishingly accurate, like predicting an electron's magnetic moment to one part in a trillion with zero failed experiments. But it contains a fundamental contradiction in its rules. The idea that our universe is one of many—the Many Worlds hypothesis—offers a radical solution. Recent experiments have demonstrated quantum behavior in increasingly large systems, from molecules containing 2,000 atoms to superconducting devices at centimeter scales. These results are strengthening the case that the equations governing microscopic particles might apply to the macroscopic world, too, making a quantum multiverse a much more likely explanation of our reality.
How it works: Quantum mechanics rests on two seemingly contradictory rules. Schrödinger’s equation says that quantum systems can exist in superpositions of multiple states, none of which can simply disappear (the cat in the box is both dead and alive). A competing hypothesis, called the Copenhagen interpretation, places a condition on how quantum systems are measured: when a measurement occurs, the quantum wave function (where all possible outcomes exist) collapses, selecting one outcome and leaving a single universe. The American physicist Hugh Everett III proposed the Many Worlds hypothesis in 1957, which leaves out this measurement postulate entirely. The wave function never collapses, and every possible outcome branches into its own world.
Cutting-edge experiments: For Many Worlds to be true, Schrödinger’s equation must hold across the universe, from the smallest to the largest scale. And several experiments point in that direction. In 2019, researchers demonstrated quantum wave properties in molecules containing 2,000 atoms. Other experiments have cooled clouds of thousands of trapped atoms enough to reveal exotic states of matter called Bose-Einstein condensates and demonstrated quantum wave behavior at centimeter scales in superconducting devices. A recent experiment sent quantum optical signals in superpositions of different light states between South Africa and China, more than 12,900 kilometers apart. If quantum superpositions persist in larger systems, then the wave function doesn’t need to collapse during measurement. Instead, every possible outcome remains part of the quantum state, producing branching worlds rather than a single universe.
Join the discussion: Do you think we live in a multiverse or a singular universe? And do you find the idea of a multiverse unsettling? Share your thoughts here.
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Seniors are spending record time on their devices, and their kids are the ones that have to help them avoid scams and AI slop. | New York Magazine ($)
Houdini died 100 years ago this Halloween. Experts are still trying to determine how. | The New York Times ($)
The Trump Administration launched an investigation into nine universities’ employment of international researchers. It could harm science, academics say. | Nature
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As Philipp Strasberg writes in this month's feature on Many Worlds, some physicists think the existence of a multiverse explains how we humans exist in the first place: if countless universes have different properties, we’d naturally find ourselves in one that could support us. It’s a mind-bending possibility. And at the same time, I think, it's a privilege to live in a universe where we can even ask the question.
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—Andrea Gawrylewski,
Chief Newsletter Editor
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