For a hundred years, the textbooks have given the same answer: gravity is not a force, and quantum gravity is perhaps impossible for that reason. A paper published in May 2025 suggests both assumptions may need revisiting.
The argument begins with a familiar problem. Einstein's general relativity describes gravity as the curvature of spacetime. Heavy objects bend the space around them. Other objects follow those curves.
The picture works beautifully for planets, stars, and even light. When physicists try to apply quantum mechanics to it, the equations produce infinities that refuse to cancel.
In this video, Sabine Hossenfelder, a physicist and science communicator, reviews the new paper and its claim to have found a way through.
Key figure
8
Papers published by Einstein on teleparallel gravity from 1928, before he set the approach aside
The Problem Einstein Left Behind
The new paper does not start from curved spacetime. It starts from flat spacetime and introduces four new bosons, one for each direction of space and time. These four carriers work together to produce all the effects normally attributed to gravity.
When combined, the four bosons generate a spin-2 particle. That is precisely what a graviton should be. And the equations reproduce, without modification, Einstein's field equations.
The trick that makes this possible is teleparallel gravity, an approach Einstein himself developed in the late 1920s. Instead of curving spacetime, teleparallelism explains gravity through torsion: a kind of twist in the way particles propagate through flat space. The accumulated effect of these twists produces the same predictions as curved spacetime at the classical level.
Einstein published eight papers on the idea. Then he abandoned it. His goal had been a unified theory of electromagnetism and gravity, and teleparallelism could not deliver that. What it may deliver instead, nearly a century later, is a route into quantum gravity.
What is teleparallel gravity?
A reformulation of Einstein's theory where spacetime remains flat and gravity acts instead through torsion, a kind of twist in how particles travel. The two approaches produce identical predictions in classical physics but may differ in how they handle quantum effects. Einstein worked on this framework from 1928 before setting it aside.
Four Bosons, Flat Space, and Quantum Gravity
The central claim is that treating gravity as a force in this way may finally make it compatible with quantum mechanics.
When the authors calculate leading quantum corrections in the teleparallel formulation, the infinities appear to cancel. They do not cancel in standard approaches to quantum gravity. That distinction, if it holds, is meaningful.
Hossenfelder describes the mechanism precisely: the four bosons recreate the torsion of teleparallel gravity, which was already known to reproduce Einstein's equations. The authors then quantize within that framework. At leading order, the infinities seem to go away.
Teleparallel gravity gives you the same effect but in flat space by adding something called torsion to the propagation of particles.
Sabine Hossenfelder, physicist and science communicator
Cautious Interest, Not a Theory of Everything
Hossenfelder is not a physicist inclined to enthusiasm. She identifies at least two significant concerns.
The calculation does not preserve all four symmetries present in Einstein's theory. The authors argue that violations are purely quantum corrections and therefore vanishingly small. She is not fully persuaded by that argument. She also notes that the paper is far from demonstrating a complete and consistent quantization of gravity.
The complexity of the framework is a separate obstacle. Flat spacetime plus four gauge bosons plus a matrix field for phase factors plus torsion in place of curvature: even if the mathematics holds together, persuading the physics community to adopt an entirely new conceptual language is its own challenge.
String theory attracted thousands of physicists despite comparable complexity, as Hossenfelder notes with dry amusement.
The paper does not claim to be a theory of everything. The press release did, however.
A New Road To A Unified Theory Of Gravity?
What it does offer is a new angle on a problem that has resisted every other approach for decades.
More On Quantum Gravity
Gravity might be a push, not a pull
Could gravity be a push rather than a pull? New physics models suggest disorder itself creates attraction.
→Einstein discarded teleparallelism because it could not unify all the forces. His successors are now asking whether, for quantum gravity alone, his abandoned framework might quietly succeed where his celebrated one cannot.
Hossenfelder, who has made videos arguing gravity is not a force, notes with some irony that those videos may one day become historical data.
The next step, she suggests, is determining whether the symmetry violations produce observable deviations from Einstein's predictions at scales current experiments can reach.
Sources
- Main source: Gravity might be a force after all (Sabine Hossenfelder, YouTube)
- Context: Backreaction: Gravity might be a force after all (Sabine Hossenfelder)
Fact Check: Claim-by-Claim Verification Verified
The article accurately summarizes a 2025 peer-reviewed paper on quantizing teleparallel gravity with four bosons, as reviewed by Sabine Hossenfelder, matching her video and blog content precisely.
Commentary
- The exact count of Einstein's teleparallel papers (claimed as 8) is plausible but not precisely confirmed in sources; likely a minor simplification.
- Paper published pre-May 2025 in Reports on Progress in Physics; article's "May 2025" aligns with Hossenfelder's video/blog date.
- Approach promising but preliminary; requires further checks on observational deviations from GR symmetries.
Sources used for verification
Academic/Peer-reviewed:
- Quantizing teleparallel gravity (main paper discussed) - iopscience.iop.org
- Einstein's teleparallelism papers, Princeton edition - einsteinpapers.press.princeton.edu
- Translation of Einstein's teleparallel unified field papers - arxiv.org
- Teleparallel gravity: from theory to cosmology (review) - PubMed
Other reliable sources:
- Gravity might be a force after all (Hossenfelder video) - YouTube
- Gravity might be a force after all (Hossenfelder blog) - backreaction.blogspot.com
Fact-checked by Perplexity Sonar Pro on 2026-03-08
