Astronomy

If our Universe were born a little differently, there wouldn’t have been any planets, stars, galaxies, or chemically interesting reactions. — 13.8 billion years ago, what we know today as our Universe began with the hot Big Bang. Filled with matter, antimatter and radiation in an almost uniform fashion, it expanded and gravitated in nearly perfect balance. As the Universe cooled, the matter and antimatter annihilated away, leaving a tiny, minuscule…

Suppose NASA astronauts had images of technological objects hovering above Earth that are not identified as human made. Should they share the data with the public or worry that such an act would generate turmoil in society? As a scientist, it is obvious to me that we must be aware…

The small moon, Enceladus, may not look like much, but hidden under its icy surface is a 6-mile deep ocean. Enceladus is less than a third the size of the moon (300 miles / 480 kilometres) but scientists believe this could be a hot spot for microbial or simple organism…

White dwarf cooling in f(R,T) gravity(arXiv) Author : Snehasish Bhattacharjee Abstract : In recent times, astounding observations of both over- and under-luminous type Ia supernovae have emerged. These peculiar observations hint not only at surpassing the Chandrasekhar limit but may also suggest potential modifications in the physical attributes of their…

Convergence of SCF sequences for the Hartree-Fock equation(arXiv) Author : Sohei Ashida Abstract : The Hartree-Fock equation is a fundamental equation in many-electron problems. It is of practical importance in quantum chemistry to find solutions to the Hartree-Fock equation. The self-consistent field (SCF) method is a standard numerical calculation method…

MHDnet: Multi-modes multiscale physics informed neural networks for solving magnetohydrodynamics problems(arXiv) Author : Xiaofei Guan, Boya Hu, Shipeng Mao, Xintong Wang Abstract : Modeling and control of the magnetohydrodynamics (MHD) system remain a challenging problem, which involves the coupling between fluid dynamics and electromagnetism with the nonlinear, multiscale spatiotemporal features…

Phase diagrams of binary ionic mixtures and white dwarf cooling(arXiv) Author : D. A. Baiko Abstract : Phase diagrams of fully ionized binary ionic mixtures are considered within the framework of the linear mixing formalism taking into account recent advances in understanding quantum one-component plasma thermodynamics. We have followed a…

Active galactic nuclei, gravitational redshifts, and cosmological tensions(arXiv) Author : S. Carneiro, N. D. Padilla, J. Chaves-Montero, C. J. Donzelli, C. Pigozzo, P. Colazo, J. S. Alcaniz Abstract : Gravitational redshift is a classical effect of Einstein’s General Relativity, already measured in stars, quasars and clusters of galaxies. We here…

Weak-field limit and regular solutions in polynomial higher-derivative gravities(arXiv) Author : Breno L. Giacchini, Tibério de Paula Netto Abstract : In the present work we show that, in the linear regime, gravity theories with more than four derivatives can have remarkable regularity properties if compared to their fourth-order counterparts. To…