Does gravity create reality? A shocking path to a theory of everything A rewrite of quantum mechanics that includes the force of gravity could finally achieve one of physicists’ biggest goals and reveal the ultimate fuzziness of time By Zack Savitsky 25 May 2026 ES Leer en Español New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine. Ryan Wills Sometimes, you work tirelessly on a problem, only to realise you have been going about it all backwards. Imagine trying to fit a massive antique piano through a tiny doorway. You have tried everything – rotating it, removing the legs, forceful shoving – but you just can’t get it to fit. Eventually, you realise it is easier to construct a room to house the piano where it already sits. Now, some physicists are grappling with a similar rethink. For decades, the accepted route to an ultimate theory of everything has involved taking our best theory of gravity and squeezing it into the frame of quantum mechanics. Given that quantum theory is wildly successful in describing the other three of the four fundamental forces of nature, it is an understandable approach. Yet, almost a century later, scientists still haven’t managed to make gravity fit. That’s why a few mavericks have championed an alternative strategy. They suggest that tweaking the equations of quantum mechanics – constructing a new room for gravity – helps explain how the strange world of particles gives rise to our everyday reality. Advertisement Various experimental avenues are opening up to probe this approach, involving everything from levitating diamonds and glowing metals to swinging pendulums and ticking clocks. The tests promise to shine a light on how the quantum world operates and guide the search for a more complete understanding of the universe. “This is like going into the open ocean: we have no clue where to go,” says Angelo Bassi, a physicist at the University of Trieste in Italy. “But maybe … by going in the wrong direction, we’ll discover the right thing.” Read more We've discovered a door to a hidden part of reality – what's inside? The world as we know it is definite. Your books rest solidly on their shelf, your clock ticks steadily forward and your cat is demonstrably alive. In the realm of atoms, however, nothing is certain. Quantum mechanics allows us to describe certain properties of particles, like their position, only in terms of likelihood. You can predict – with great success – the odds of finding a particle in one of many places, but where it will be observed in a given test is completely unknowable. Before that measurement happens, the object exists in a wave-like blur of all those possibilities at once, which we describe mathematically with something called a wave function. Subscriber-only newsletter Sign up to Lost in Space-Time Untangle mind-bending physics, maths and the weirdness of reality with our monthly, special-guest-written newsletter. Sign up to newsletter New Scientist. Science news and long reads from expert journalists, covering developments in science, technology, health and the environment on the website and the magazine. This leaves us with two big conundrums that lie at the heart of quantum theory. For one, it is unclear how and when the fuzzy quantum world gives rise to classical concreteness. The other problem is that this probabilistic description clashes with Albert Einstein’s classical understanding of gravity. Efforts to recast Einstein’s work on gravity into the language of forces and particles have resulted in constructions such as string theory that are cumbersome and practically untestable. A long-standing assumption has been that, deep down, everything is quantum. But a century after the inception of quantum mechanics, physicists are still struggling to make a cohesive story out of it. “There must be something else going on, and we have to understand what,” says Bassi. “The important step is to push quantum mechanics to its limits.” One route to finding these limits involves one of the many oddities of quantum mechanics: the principle of superposition. Scientists today routinely put a single particle into a mixed state of being in two distinct locations, a trick they can verify with interference patterns from those interacting possibilities. But once they measure where the particle is, it collapses into one definitive state: either left or right, say. There are many possible explanations of what happens when a measurement occurs – as evidenced by the variety of interpretations of quantum mechanics. The many-worlds interpretation says that each possible scenario plays out in a different branch of reality, while the Copenhagen interpretation says, essentially, to trust the maths. A skydiver, skydiving Some physicists want to adapt quantum mechanics to include the classical force of gravity Hans Berggren/Getty Images Another group of explanations searches for a physical solution. In the 1980s, physicists Giancarlo Ghirardi, Alberto Rimini and Tullio Weber proposed that some invisible process was tampering with quantum waves, causing them to suddenly collapse. In the following years, physicist Lajos Diósi at the Wigner Research Centre for Physics in Hungary and University of Oxford mathematician Roger Penrose proposed that gravity could be a culprit for this mysterious process. Essentially, the Diósi-Penrose model argues that, in the battle between quantum and gravity, quantum cracks first. The basic premise the pair set out was that putting a large mass into a superposition would force space-time to curve in two different ways – something it cannot permit. They proposed that the integrity of space-time prevails and causes the quantum waves to collapse. If this is the case, superpositions would have a lifetime that is inversely proportional to the square of their mass. Quantum objects could live in a superposition for very long periods of time, but the larger the object was, the faster it would collapse. This would explain why we never see larger objects in superposition – because their substantial gravitational tug would instantly force a collapse. It also tackles the thorny problem of measurement, because any device large enough to detect and relay information about a quantum system would become part of that system and disturb it gravitationally. This idea moved the discussion away from merely interpreting quantum theory and instead towards revising it.