Physicists at Odds Over Greatest Physics Mysteries
PiMuNu writes:
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 APS conducted last summer.
Building on an earlier survey, the American Physical Society's "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
https://physics.aps.org/articles/v19/34
[...] 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 CDM, 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 -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!
Some tidbits:
* Almost 40 % of physicists support the Copenhagen interpretation of quantum mechanics
* [...] 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.
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