Far from Settled: Respondents at Odds over Greatest Physics Mysteries
Mysteries by their very nature don’t invite consensus. Without a clear answer, people’s opinions tend to diverge over what the most likely solution is. Physics mysteries are no different, as evidenced by the results of a survey we conducted last summer.
Building on an earlier survey by two of us (N.A. and P.H.), Physics Magazine ran a ten-question survey that covered some of the biggest controversies in cosmology, particle physics, and general relativity. More than 1600 people took the time to share their opinions with us, making this, to our knowledge, the largest survey to date focused on physicists’ views of open questions in physics (distinct from broader previous surveys addressing careers, education, or the physics workforce). We are especially thankful to participants who, amid busy schedules, provided careful and thoughtful responses.
The complete set of survey results and charts are presented in an e-print [1]. In an accompanying video, we discuss the results with cosmologists Sean Carroll from Johns Hopkins University in Maryland and Ghazal Geshnizjan from the Perimeter Institute in Canada.
The survey respondents came from a diverse background. A little over 20% of the participants called themselves “science enthusiasts,” with the rest identifying as researchers in one of four categories: gravity (10%), astrophysics (12%), particle physics (18%), or another field of science (30%).
Only one topic revealed close alignment: how to think about the “big bang.” A large majority (70%) chose to describe it as a hot, dense state without committing to whether it corresponds to an absolute beginning of time or not. We found this alignment significant, as it suggests that the big bang is no longer widely considered the beginning of the Universe. The only other question that had a majority answer was that on early-Universe cosmology: Just over half of respondents selected “cosmic inflation” as the best explanation of early-Universe conundrums.
The survey revealed considerable skepticism over the standard model of cosmology, called ΛCDM, which stipulates the type of dark energy and dark matter that dominate the Universe’s energy budget. Dark matter is typically assumed to be a new class of particle outside of the standard model of particle physics. However, a weakly interacting massive particle (WIMP), once a clear front-runner, was picked by only 10% of respondents. Larger fractions favored what were once considered less-mainstream possibilities: 17% chose a light particle such as an axion; 22% pointed to possible modification to Einstein’s theory of gravity (either modified Newtonian dynamics [MOND] or quantum gravity); and around 21% made the safe bet, saying that dark matter might be a hybrid combination of all the above.
Dark energy was equally contentious. The traditional standard bearer—the cosmological constant Λ—received only about 25% of the votes, finishing neck and neck with the leading dark energy contender—a time-varying scalar field. A third option—involving some type of gravity modification—garnered much of the remaining votes.
Taken together, the dark matter and dark energy results point to a shift away from traditional views. The standard model of cosmology has far less support than one might imagine from its name!
The survey also probed views on the so-called fine-tuning of the constants of nature—often presented as forcing a choice between a multiverse or an intelligent designer. Neither of those options prevailed, with the single most popular choice being that the constants are “brute facts” that need no further explanation.
Quantum physics remains deeply puzzling. We find it remarkable—if perhaps unsurprising—that the interpretation of quantum mechanics is far from settled a century after its development. In the survey, the Copenhagen interpretation emerged as the leading view (over 35%), consistent with the results of another recent survey focused on the issue. Comparable divisions appeared in black hole physics. About 40% of respondents subscribed to the textbook view that matter falling into a black hole will be crushed into a singularity. On the black hole information paradox, more than half of respondents said information is ultimately preserved (either in Hawking radiation or in a black hole remnant) though a substantial minority (just under 20%) disagreed.
As for the leading candidate for a quantum theory of gravity, string theory remains the front-runner. But with less than 20% support, physicists remain divided on this topic. In fact, “no opinion” was the most selected answer.
Interestingly, we found some answers showed correlations. For example, about 5% of respondents chose quantum gravity—a theory often associated with extremely high energy—as the solution to several outstanding mysteries (including early-Universe cosmology, dark matter, dark energy, and the Hubble tension), which are all related to lower energy scales. The concordance amongst responses to these questions is 3–4 times larger than expected by random chance.
Readers can investigate other correlations through a dashboard program created by N.A. And we invite scientists and historians of science to explore and independently analyze this rich dataset (full, anonymized survey results can be downloaded here).
Correction (18 May 2026): This article originally described the survey as “the largest survey ever conducted in physics.” Larger surveys addressing broader topics in physics have previously been conducted, including a 2020 American Institute of Physics survey that collected responses from more than 30,000 scientists—including 7570 physicists—on issues related to careers and professional experiences. The text has been updated to clarify that the present survey concerns physicists’ views on open questions in fundamental physics.
–Niayesh Afshordi
Niayesh Afshordi is an astrophysicist at the University of Waterloo and the Perimeter Institute in Canada.
–Phil Halper
Phil Halper is a science communicator based in the UK.
–Matteo Rini
Matteo Rini is the Editor of Physics Magazine.
–Michael Schirber
Michael Schirber is a Corresponding Editor for Physics Magazine based in Lyon, France.
References
- N. Afshordi et al., “Big Mysteries Survey: Physicists’ views on cosmology, black holes, quantum mechanics, and quantum gravity,” arXiv:2605.11058.