Largest-Ever Survey of Physicists Challenges Popular Narrative About the Big Bang
A major new study— the largest survey of physicists ever conducted—reveals that scientists are far more divided on fundamental questions than is often portrayed, and that several views commonly attributed to physicists are not as widely supported.
Physics Magazine, published by the American Physical Society (APS), polled its readers and the APS membership in the “Big Mysteries Survey,” receiving 1,675 responses. The survey covered controversial topics including the Big Bang, dark matter, dark energy, and quantum mechanics.
Of the ten topics examined, only one produced a clear consensus: 68% of physicists believe the Big Bang should not be understood as the beginning of time, but rather as a theory describing the universe’s evolution from a hot, dense state. Remarkably, this was exactly the same figure that the authors obtained in a smaller survey conducted at a conference of physicists in Copenhagen. This challenges the common public narrative that time itself began at the Big Bang, a result often said to be implied by Einstein’s theory of relativity. But, as theoretical physicist at Johns Hopkins University, Sean Carroll, said in an accompanying video explaining the results: “Einstein’s theory of general relativity isn’t correct in that regime because it doesn’t include quantum mechanics.”
Only one other idea received majority support: cosmic inflation—the theory that the early universe underwent a rapid expansion—though it only narrowly crossed the threshold at 51%.
On many other issues, physicists were far more divided. Notably, the standard cosmological model, known as ΛCDM (Lambda Cold Dark Matter), did not receive majority backing. This model posits that the universe is dominated by dark energy, represented by the Greek letter Λ (lambda), which is assumed to be constant over time and drives eternal accelerated cosmic expansion. However, recent findings from the Dark Energy Spectroscopic Instrument (DESI) suggest that dark energy may change over time. Perhaps reflecting this, the most popular response in the survey favored a time-varying form of dark energy over the traditional constant. If correct, the ultimate fate of the universe may not be the heat death that is often described and could even be a “Big Crunch.”
Similarly, no single explanation for dark matter received majority support. While long assumed to consist of undiscovered particles, decades of experimental searches have yet to confirm their existence. Survey responses were split among high-mass particles, low-mass particles, and hybrid explanations. Even combining particle and hybrid explanations did not cross the majority threshold.
Another striking result concerns so-called “fine-tuning.” Contrary to claims that life-permitting constants are unlikely and demand explanation—such as a multiverse or an intelligent designer—the most common response was that they may simply be brute facts. Some thinkers have questioned whether it is meaningful to talk about probabilities for constants whose values never change. As cosmologist and co-author of the study, Niayesh Afshordi of the University of Waterloo and Perimeter Institute, puts it, “most physicists don’t quite sympathize” with the idea that these constants require explanation.
Elsewhere, leading theories such as string theory and the Copenhagen interpretation of quantum mechanics remained the most popular options in their fields, but with only modest support (19% and 36%, respectively).
Another vexing issue for physicists is the information paradox highlighted by Stephen Hawking. This is a deep puzzle, as one leading theory, general relativity, implies information should be destroyed in black holes, whilst another, quantum mechanics, implies it should be preserved. While it’s often said to be resolved in favor of information preservation, a significant minority (19%) still support information loss—Hawking’s original view.
The survey highlights the gap between public perceptions of scientific consensus and the diversity of views within the physics community. As co-author Phil Halper notes:
“Controversies in physics are decided by data, not votes—but surveys like this are valuable, especially in how scientific thought is communicated to the public. Our results question whether the many opinions attributed to physicists are actually supported by them.”
These results are presented in an article in Physics Magazine, an academic paper on arXiv, and in a YouTube video in which physicists Sean Carroll and Ghazal Geshnizjani discuss the results with Niayesh Afshordi and Phil Halper, who co-authored the survey and wrote the popular book Battle of the Big Bang.
Related resources: open the interactive dashboard, read the Physics Magazine article, open the anonymized survey data, watch the YouTube teaser, or watch the full discussion video.