The GUT Theory.
There is a general aesthetic among high energy physicists that the more symmetrical a theory is, the more "beautiful" and "elegant" it is. According to this aesthetic, the Standard Model gauge group, which is the direct product of three groups , is "ugly". Also, reasoning in analogy with the 19th-century unification of electricity with magnetism into electromagnetism, and especially the success of the electroweak theory, which utilizes the idea of spontaneous symmetry breaking to unify electromagnetism with the weak interaction, people wondered if it might be possible to unify all three groups in a similar manner. Physicists feel that three independent gauge coupling constants and a huge number of Yukawa coupling coefficients require far too many free parameters, and that these coupling constants ought to be explained by a theory with fewer free parameters. A gauge theory where the gauge group is a simple group only has one gauge coupling constant, and since the fermions are now grouped together in larger representations, there are fewer Yukawa coupling coefficients as well. In addition, the chiral fermion fields of the Standard Model unify into three generations of two irreducible representations in SU, and three generations of an irreducible representation in SO. This is a significant observation, as a generic combination of chiral fermions which are free of gauge anomalies will not be unified in a representation of some larger Lie group without adding additional matter fields. SO also predicts a right-handed neutrino.
GUT theory specifically predicts relations among the fermion masses, such as between the electron and the down quark, the muon and the strange quark, and the tau lepton and the bottom quark for SU and SO. Some of these mass relations hold approximately, but most don't. See Georgi-Jarlskog mass relation. If we look at the renormalization group running of the three-gauge couplings have been found to nearly, but not quite, meet at the same point if the hypercharge is normalized so that it is consistent with SU/SO GUTs, which are precisely the GUT groups which lead to a simple fermion unification. This is a significant result, as other Lie groups lead to different normalizations. However, if the supersymmetric extension MSSM is used instead of the Standard Model, the match becomes much more accurate. It is commonly believed that this matching is unlikely to be a coincidence. Also, most model builders simply assume SUSY because it solves the hierarchy problem—i.e., it stabilizes the electroweak Higgs mass against radiative corrections. And the Majorana mass of the right-handed neutrino SO theories with its mass set to the gauge unification scale is examined, values for the left-handed neutrino masses are produced via the seesaw mechanism. These values are 10–100 times smaller than the GUT scale, but still relatively close.
My Favourite: Hawkins Theory.
In simple language we may describe the formation of a celestial object called as black hole. It is believed that when a star is sufficiently massive, gravitational collapse may continue until the density is so high and gravity predominates to such an extent that a black hole results. Objects believed to be massive black holes have been found at the center of some galaxies- they appear to power very luminous objects such as quasars and active galactic nuclei. Matter and radiation cannot escape from a black hole due to its immense gravitational field, but as material falls towards it intense radiation is emitted.
Although black holes are assumed to be some kind of monsters in the space-time swallowing every thing matter or radiation approaching near them in a frenzied cosmic feast. The physicists now a days think that rather than being a space menace these objects may be fundamental to the creation of galaxies. Black holes are regions of space where gravity is so strong that not even light can escape, making them impossible to see. However, the staff that is being sucked into those massive cosmic vacuum cleaners could be ‘seen’. Anything that approaches a black hole is first torn apart by its immense gravitational and then forms a flat rotating disc that spirals into the hole. As the debris gets closer and closer to the mouth of the black hole it speeds up and the bits start to smash together. The material heats up due to this friction. When this happens around a black hole, x-rays are given off which we can detect. If the black hole is really very large and has lots of debris in the disc, then it can reveal itself as one of the brightest objects in the universe- a quasar.
It is hypothesized that active galactic nuclei are capable of converting dark matter into high energy protons. Yurii Pavlov at The Herzen University in St Petersburg and Grib, hypothesize that dark matter particles are about 15 times heavier than protons, and that they can decay into pairs of particles of a type that interacts.
Near an active galactic nucleus, one of these particles can fall into the black hole, while the other escapes, as described by the Penrose process. Some of the particles that escape will collide with incoming particles creating collisions of very high energy. It is in these collisions, according to Pavlov, that ordinary visible protons can form. These protons will have very high energies.
According to Pavlov evidence is present in the form of ultra high-energy cosmic rays.