Physics can explain how fundamental particles, forces and space-time behave, but not what their intrinsic nature is, so at the moment, we just know what they do, but not what they are.
The successful Standard Model of particle physics was developed in the early 1970s and it is our best understanding of how the fundamental particles and the fundamental forces that make up the Universe are related, and is incredibly precise and accurate in its predictions, however, it does not explain gravity, the nature of dark matter and dark energy, or the matter/antimatter asymmetry in the Universe.
According to Quantum Mechanics, the properties of physical systems remain undefined until they are measured, however in the many-worlds interpretation of quantum mechanics all possible outcomes of measurement are actually realised in different parallel universes, but can that ever be proved?
The measuring problem refers to the challenge of understanding and explaining the process by which a quantum system transitions from a superposition of multiple states, where it simultaneously embodies all possible outcomes, to a single, well-defined state when it is measured or observed. How and why does this collapse occur remains a mystery.
Quantum mechanics is very successful describing reality at atomic level, while Relativity is very accurate at cosmic scales, however when it comes to describing gravity, these theories produce incompatible results, which suggests that something fundamental is missing in physics.
The maximum possible speed in nature at which all massless particles and field perturbations travel in vacuum, including electromagnetic radiation, gravitational waves, gluon fields or the weak interaction, is a universal physical constant equal to 299,792,458 meters per second, but we don’t know why it has that value.
The speed of light in vacuum is a universal physical constant and it is the same for all observers irrespective of their frame of reference. This can be proved experimentally, however, we do not have a theoretical justification for the constancy of the speed of light.
Neutrinos are the most abundant matter particles in the Universe. The discovery in 1998 that neutrinos change “flavours” as they move through the Universe, had the surprising implication that neutrinos do have at least a small amount of mass, something not predicted by the otherwise successful Standard Model of Particle Physics. Scientists still do not know the measure of the neutrino mass nor where that mass comes from.
Cosmic rays were discovered in 1912, they are composed mainly of high-energy protons and nuclei of atoms constantly raining on Earth. Some come from the Sun, but the majority from unknown sources in our Milky Way and distant galaxies.
The reason why a proton, which is made up of 3 quarks, has exactly the same opposite charge of the electron, which is a completely different particle, is a mystery.
Theoretical physicists have predicted the existence of magnetic monopoles, hypothetical elementary particles with just one magnetic pole (north pole without south, and south pole without north), but they haven’t been found yet.
Bell’s Theorem in 1964, one of the greatest discoveries in science, proves that quantum physics is incompatible with certain types of local hidden-variable theories such as the one proposed by Einstein and others. This implies the existence of interactions between events that are too far apart to be connected even by signals travelling at the speed of light. This has been proved experimentally, but we don’t know why it happens.
Entanglement is the mysterious phenomenon in which 2 separate particles can communicate to each other their quantum state instantaneously, in a way that one particle of an entangled pair is instantly affected by the outcome of a measurement performed on the other particle, no matter how far apart they are. There is plenty of experimental evidence of this, but we don’t really know why it happens.
Supersymmetry is a theory that predicts the existence of partner particles for the members of the successful Standard Model of particle physics. This theory would solve nearly all of the lingering problems in fundamental physics, however, after decades of searching and many experiments, physicists have yet to find proof that it exists.
It is widely believed, that in the very early Universe when temperatures were extremely high, the weak, electromagnetic, and strong forces, and even gravity, were unified into a single force, and then when the temperature dropped, these forces separated from each other leaving us with the four distinct forces that we can now observe in the Universe. There is however no experimental evidence for the unification of all fundamental forces.
Preons are point particles theorised to be sub-components of quarks and leptons, they are intending to resolve some anomalies and unexplained phenomena of the otherwise successful Standard Model of particle physics, however no empirical evidence of preons has been found so far.
Sterile neutrinos, predicted but not found yet, are hypothetical fundamental particles that would interact only via gravity. They are one of the candidates to explain the mysterious dark matter or the unbalance between matter and antimatter in the observable Universe.
On distances smaller than 10⁻³⁵ meters (Planck length unit), and on timescales shorter than 10⁻⁴³ seconds (Planck time unit), our conventional laws of physics (Standard Model, quantum field theory, and general relativity) break down and there is no way to describe anything meaningful.
Today’s mainstream belief in physics is that spacetime is not fundamental but emerges as a result of processes taking place at the level of quarks and their conglomerates. If so, the mechanism for these processes is unknown.
Quantum mechanics suggests that NOTHING is inherently unstable, and therefore the arising of SOMETHING was inevitable, however Science does not have a clear answer to the question: Why is there something instead of nothing?
Awarenergy 