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The unresolved problems in contemporary astrophysics and cosmology.
...These two disciplines are literally collapsing under the mass of unresolved problems. Historically, the study of the cosmos has gone through several stages. We will not retrace the history of astronomy here. Spectroscopy made it possible to obtain important data on the composition and temperature of objects, and the measurement of the Doppler effect made it possible to obtain velocity fields and to determine stellar masses, at distances exceeding by a great many orders of magnitude the diameter of the solar system. The discovery of distance standards (Cepheid variable stars) made it possible to extend these distance measurements, up to cosmological scales (50 million light-years).
...The application of the tools of differential geometry to cosmology (field equation) made it possible to take another look at certain phenomena (cosmic expansion, local relativistic phenomena).
...The discovery of nuclear physics made it possible to construct models of stars. But we saw earlier that, abruptly, the mastery that man believed he possessed over the functioning of stars was suddenly called into question.
...This same nuclear physics made it possible to go further back into the past and to explain, for example, the abundance of helium.
But:
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There is no theoretical model of a galaxy. In this field we have not gone beyond the stage of empiricism.
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We know neither how these objects form, why they have such and such a mass and not another, nor how they evolve. The shape of the rotation curve of galaxies, which shows a high peripheral velocity, remains a mystery.
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Theories of spiral structure, based solely on numerical simulations, remain highly contestable.
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There is a considerable discrepancy between mass measurements and measured velocity fields (phenomenon of missing mass).
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The same dissonance concerning galaxy clusters.
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There are many very irregular galaxies, about which the English astronomer Sir James Jeans had said "When one sees such shapes one cannot resist the idea that this is due to considerable forces, which are at work in the cosmos, and whose nature we ignore"
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At the level of cosmology there is a certain disagreement between the age of the universe, estimated from the oldest stars in our galaxy and from measurements on expansion (Hubble law, Hubble constant)
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We cannot explain the large-scale, lacunar structure of the universe, with galaxies distributed around immense voids.
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Numerous pairs of galaxies have been brought to light that violate the Hubble law (the nearer one has a higher red shift than that of the second, located in the background).
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Sources with very high red shift have been discovered, whose size does not exceed that of the solar system and which emit as much energy as an entire galaxy (quasars). Source of energy unknown. Some astronomers think that these sources are nuclei of "active galaxies" (Seyfert galaxies). But when they are asked for the definition of an "active galaxy", whose nucleus seems to be in a state of explosion, they answer "that it harbors a quasar at its center".
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At a rate of one per day, on average, astronomers record gamma-ray flashes. Mechanism, distance and nature of the emitter: unknown.
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The effects of gravitational mirage, linked to galaxies and galaxy clusters, do not correspond to the masses of the said objects.
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Theory predicted the existence of remnants of massive stars, neutron stars. In general, when an object has been predicted by a visionary theoretician (like supernovae by the American Fritz Zwicky in 1931) several of them were quickly discovered, then hundreds: neutron stars (which, in rapid rotation, give what are called pulsars). These are frequently associated with another star which, by the mass it sends them, must necessarily, from time to time, make them exceed their "critical mass", evaluated at 2.5 solar masses. Under these conditions the neutrons that constitute them, packed against one another, can no longer counterbalance the force of gravitation and the object collapses upon itself. We do not know how to describe this collapse. The black hole model, called to the rescue as a solution of the field equation, presents a troublesome defect. It is a solution of:
S = 0
that is to say of an equation where T = 0, describing a region of space where the energy-matter density is zero. Moreover, what militates against this model is the rarity of black hole candidates, for thirty years, although these objects are used, putting them into every sauce, to "explain" anything and everything else.
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Returning to cosmology, to the standard model, called the "Big Bang", this one cannot explain the remarkable homogeneity of this fossil trace of the primitive universe that constitutes the radiation background at 2.7°K. According to this model, in the earliest infancy of the universe, two neighboring particles move away from one another at a speed greater than c. They therefore cannot interact. The primitive universe was therefore non-collisional. So, why was it so homogeneous?
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It is impossible to define time from a certain stage, going back into the past. In any case, the description of the universe, in its hyperdense and hyperhot state, is penalized by the current crisis in high-energy physics.
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The standard model, founded on a solution of the Einstein equation, does not know how to take electromagnetic phenomena into account. More generally, the link between particle physics and the large-scale behavior of the cosmos is not made. Although there exists a journal entitled "Classical and quantum gravity", the method of quantification could not be extended to gravitation. We do not know how to define a possible graviton.
Fifty years of non-physics.
...The scientific crisis is in fact total and is not limited to astrophysics and cosmology. The predictive successes of quantum mechanics are an illusion. Many parts of the theory remain in the domain of the semi-empirical. For example, there is no means of relating the masses and electric charges of particles. We do not know how to predict particle masses. The quark model looks distressingly like that of Ptolemy's epicycles. Quantum mechanics is powerless to explain the solar neutrino deficit.
...Although the majority of theoretical physicists currently turn toward the world of superstrings (for lack of having a different idea) this "new discipline" has proved itself incapable, for thirty years, of accounting for the slightest observation, nor of suggesting the slightest experiment. According to the mathematician Jean-Marie Souriau (who has his own definition of theoretical physics: mathematics minus rigor. Physics, minus experience), we have just lived through "fifty years of non-physics". He considers that no discovery of theoretical physics worthy of the name has occurred since the work of Feynmann, which dates from the fifties.
...A few years ago, showing me the minutes of an international colloquium on superstrings, he had read me a passage from the introductory speech of the person in charge of this colloquium:
- Although the theory of superstrings has to this day predicted no phenomenon nor made it possible to interpret any experiment or observation, given the number of papers that are now being published one will note the extreme vigor of this new discipline.
The world of research.
...There are more researchers at work, throughout the world, than there have ever been in the history of science. Budgets and technical means are substantial. Yet one would be hard pressed to designate a physicist of whom one could be sure that he will leave a name in the history of science. Between 1895 (discovery of radioactivity by Becquerel) and 1932 (discovery of the neutron by Chadwick) thirty-seven short years elapsed. It would be useless to recall all the profound upheavals of our vision of the world that shook this period and the string of eminent scientists who attached their name to this era. Conversely, what has happened since 1961, on the science scene, if one excepts technological advances (conquest of the Moon, telecommunication satellites, computing, Cd rom, etc...)?
All our science seems to be living in a paradigmatic confinement.
...According to Souriau, the generalization, in the post-war period, of the system of reading committees, supposed to guarantee the independence of the "referees" (experts in the discipline concerned), during the examination of work, has provoked a catastrophic backlash effect. Anonymity engenders the most total impunity, facilitates the blocking of new ideas, always disturbing..
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