While the UAP phenomena demonstrate extraordinary capabilities, it should not be forgotten that our knowledge in the field of fundamental physics is still very fragmented, even stagnant at the beginning of the 21st century. In astrophysics, observational contradictions are piling up, whereas in the last century, science had succeeded in making many observations predicted by theory. The challenges to be solved are numerous, and the unification of quantum physics with relativity seems far away.
In the field of energy, fusion control is hampered by the instability of magnetically confined plasmas and has still not achieved an energy efficiency that would allow an industrial exploitation. Obviously, we do not yet understand the mechanisms underlying the functioning of gravity, despite it being a major key to mankind one day being able to travel to the stars. If our rockets use the principle of action/reaction with the ejection of hot gasses to propel themselves out of the Earth's gravitational pull, this can in no way be applied for interstellar travel. A new means of propulsion without mass ejection is therefore essential. Even worse, measurement of the rotation of stars inside galaxies remains an unresolved fundamental issue in physics.
If dark matter is not involved, how do we explain the rotation speed of galaxies?
Two astronomers have presented a study of binary stars that goes against the dark matter theory and supports MOND, the modified theory of gravity. Science is trying to explain :
- Why galaxies rotate too fast?
- Why star clusters move too fast?
- Why the effect of gravitational lensing is far too strong?
- Why a cosmic microwave background in the microwave wavelength range is different from what is expected?
- Why the universe is far too structured for its supposed age?
These observations do not correspond to the known and accepted laws of general relativity.
Physicists first postulated the existence of an undetectable transparent substance between galaxies called dark matter so that they would not have to modify the classical equations of relativity. In the absence of any evidence in favor of this hypothesis in decades, are we witnessing a MOND comeback?
More evidence in favor of MOND?
The Modified Newtonian dynamics theory MOND proposed in 1984 is a theory that solves the problem of the rotational velocity of spiral galaxies by slightly altering the behavior of gravity if the gravitational field is very weak. Observations show that stars far from the center of galaxies does not rotate at the speed predicted by general relativity.
In the current classical theory, the more massive a body is, the more it bends space-time to its proximity with a proportionality relative to distance. But based on observations, the theory runs into a problem of missing mass in an estimated factor of about 6 - hence the invention of an additional, non-visible mass called dark matter.
The MOND theory is an alternative to the concept of dark matter, the existence of which has not yet been demonstrated. To date, no observations or particles have been made that could support the existence of so-called dark matter.
The MOND theory correctly predicts the observed rotation of galaxies, but does so less well in other cases studied by astrophysicists. Pre-2012 data for binary stars (provided they were far enough apart) also didn't seem to confirm MOND very well. Although important unknowns about the inclination and eccentricity of the orbits remain, one can consider that the very large amount of data cancels out the bias. More recent data, collected by the GAIA mission on the movements of millions of stars over five years starting 2013, gets much more precise, although significant unknowns about the inclination and eccentricity of the orbits remain, but we can consider that the very large amount of data cancels out the bias.
Two new statistical studies of this data, done in a more rigorous way in 2023, confirm a strengthening of the relevance of MOND as well as that of a version of MOND called EQUAL, in a case where binary stars would be separated beyond a certain distance. Due to the very large amount of data used, the accuracy of the study is estimated at 10 sigma, which makes it one chance in 10,000 billion that chance has distorted the measurements.
But their authors will not access fame, because another study, also from 2023 and using the same data, concludes that classical general relativity is indeed valid, including on large distances. In total, 4 studies using the same data have given four different results. A fifth study, using Bayesian statistics, is expected to try to decide between them.
The MOND theory is far from perfect and struggles to explain how large cosmic structures are formed. In addition, MOND involves ad hoc modifications to Newton's laws of gravity to adjust observations, which can be considered theoretically unsatisfactory. The short distance between binary stars also may seem not demonstrative given the enormous sizes of galaxies, but it should be remembered that the 2 Voyager probes also note this speed differential effect even as they are traveling on the edge of the solar system.
The study of binary stars has at least the merit of determining a precise distance threshold of about three astronomical units (AU) beyond which this divergence appears with the classical Lambda CDM theory which makes it necessary to have the presence of dark matter, as well as the addition of another form of matter, dark energy, which has a repulsive effect on the expansion of the Universe. More recently, an additional problem concerning gravitation and unexplained differences in the expansion rate of the Universe, named the S8 Tension, has been discovered.
The only certainty for now: despite the relevance and efforts of our brightest minds, there is something that is still not right, up in the stars, circling above us. Perhaps if a UAP one day flies over the LIGO detector or other sophisticated sensors, we will have some more clues as to how gravity works, and, in a few centuries, a technological application that will finally allow us to visit the stars and thus ensure the long-term sustainability of the human species.
Readers interested in this topic can look for further information in 4 studies using GAIA data:
-Chae (2023 in favor of AQUAL MOND)
-Hernandez (2023 in favor of MOND)
-PIttordis & Sutherland (2023 in favor of general relativity)
-Hernandez, Cookson & Cortés in favor, neither of MOND nor of general relativity.
Main picture: Image by Garik Barseghyan from Pixabay
