Philosophical Reflections on Facilitating Paradigm Shifts

A paradigm shift by definition is a major change in scientific understanding that upends and replaces a prior paradigm. Over the past 47 years, I have made a number of paradigm shifts in the geosciences, planetary sciences, and astrophysical sciences. These include the composition of the inner core and deep interior of Earth, recognizing that Earth’s early formation as a Jupiter-like gas giant makes it possible to derive virtually all the geological and geodynamic behavior of our planet, including the origin of mountains characterized by folding, the primary initiation of fjords and submarine canyons, the origin and typography of ocean floors and continents (described in Whole-Earth Decompression Dynamics), which upends and replaces plate tectonics theory, Earth’s previously unanticipated, powerful, and variable energy sources, namely, a terra-centric nuclear fission georeactor and the stored energy of protoplanetary compression, the nuclear georeactor origin of Earth’s magnetic field and the reasons for its variability. I also revealed a new concept that explains the thermonuclear ignition of stars and, concomitantly, the dark matter surrounding galaxies, the origin of heavy elements, and the reason why the vast multitude of galaxies in the universe display just a few prominent patterns of luminous stars. Recently, I discovered that particulate pollution, not carbon dioxide, is the primary cause of anthropogenic global warming. These are paradigm shifts which, unless successfully refuted, provide new, more-correct logical pathways for future discoveries. Here I reflect on some aspects of my personal science philosophy that has facilitated these fundamental paradigm shifts.

Nature of the Universe: Astrophysical Paradigm Shifts

Over my lifetime I have witnessed the decline of scientific capability and integrity in the physical sciences. When a new idea arises, it should be discussed and debated. Attempts should be made to refute the new idea; otherwise, it should be cited in subsequent literature. That is the way science progresses, not by attempting to suppress a new idea or failing that, to ignore it. But all too often, in instances of discoveries or insights that might cause major paradigm shifts, suppression or non-recognition is what happens. Here, I describe, from a first-person perspective, several paradigm shifts in astrophysics that have been systematically ignored, including the thermonuclear ignition of stars, the nature of dark matter, why vast numbers of galaxies have just a few prominent patterns of luminous stars, the origin of chemical elements, and a new speculation about the nature of the Universe.

Predictions for the hydrogen-free ejecta of pulsational pair-instability supernovae

Present and upcoming time-domain astronomy efforts, in part driven by gravitational-wave follow-up campaigns, will unveil a variety of rare explosive transients in the sky. Here, we focus on pulsational pair-instability evolution, which can result in signatures that are observable with electromagnetic and gravitational waves. We simulated grids of bare helium stars to characterize the resulting black hole (BH) masses together with the ejecta composition, velocity, and thermal state. We find that the stars do not react “elastically” to the thermonuclear ignition in the core: there is not a one-to-one correspondence between pair-instability driven ignition and mass ejections, which causes ambiguity as to what is an observable pulse. In agreement with previous studies, we find that for initial helium core masses of 37.5 M⊙ ≲ MHe, init ≲ 41 M⊙, corresponding to carbon-oxygen core masses 27.5 M⊙ ≲ MCO ≲ 30.1 M⊙, the explosions are not strong enough to affect the surface. With increasing initial helium core mass, they become progressively stronger causing first large radial expansion (41 M⊙ ≲ MHe, init ≲ 42 M⊙, corresponding to 30.1 M⊙ ≲ MCO ≲ 30.8 M⊙) and, finally, also mass ejection episodes (for MHe, init ≳ 42 M⊙, or MCO ≳ 30.8 M⊙). The lowest mass helium core to be fully disrupted in a pair-instability supernova is MHe, init ≃ 80 M⊙, corresponding to MCO ≃ 55 M⊙. Models with MHe, init ≳ 200 M⊙ (MCO ≳ 114 M⊙) reach the photodisintegration regime, resulting in BHs with masses of MBH ≳ 125 M⊙. Although this is currently considered unlikely, if BHs from these models form via (weak) explosions, the previously-ejected material might be hit by the blast wave and convert kinetic energy into observable electromagnetic radiation. We characterize the hydrogen-free circumstellar material from the pulsational pair-instability of helium cores by simply assuming that the ejecta maintain a constant velocity after ejection. We find that our models produce helium-rich ejecta with mass of 10−3 M⊙ ≲ MCSM ≲ 40 M⊙, the larger values corresponding to the more massive progenitor stars. These ejecta are typically launched at a few thousand km s−1 and reach distances of ∼1012 − 1015 cm before the core-collapse of the star. The delays between mass ejection events and the final collapse span a wide and mass-dependent range (from subhour to 104 years), and the shells ejected can also collide with each other, powering supernova impostor events before the final core-collapse. The range of properties we find suggests a possible connection with (some) type Ibn supernovae.

Source of megaampere current with the rise time ∼100 ns on the basis of explosive magnetic generator

To achieve a thermonuclear ignition threshold in the scheme of indirect irradiation of Z‑pinch by X‑radiation, it is necessary to implode the liner by the current with the amplitude 65 МА for the time 100 ns. The currents with such parameters can be achieved with the use of super-power disk explosive magnetic generators and a two-stage current pulse sharpening system based on foil electrically exploded current opening switches in a form of a serpentine. The implementation of the explosive current source with a rise time of 100 ns is advisable to be carried out in stages by increasing the magnitude of current. The results of the first-stage experiments, in which the current with the amplitude of 5 MA was produced on the basis of the helical explosive magnetic generator in the load of 10 nH for the time of 110 ns, are presented.