"Did you know time can slow down near black holes by up to 30%?
According to Einstein's theory of general relativity, massive objects warp spacetime, causing time dilation near event horizons. This effect is predicted to be extreme, potentially slowing down time by millions of years.
As Einstein said, "Time and space are not independent of each other."
What's the weirdest consequence of time dilation you can think of?
Weekly Update from the Open Journal of Astrophysics – 16/05/2026
It’s Saturday once again, so time for another update of activity at the Open Journal of Astrophysics. Since the last update we have published a further five papers, bringing the number in Volume 9 (2026) to 104 and the total so far published by OJAp up to 552. It took us until late July to pass 100 last year.
I will continue to include the posts made on our Mastodon account (on Fediscience) to encourage you to visit it. Mastodon is a really excellent service, and a more than adequate replacement for X/Twitter (which nobody should be using); these announcements also show the DOI for each paper.
The first paper to report this week, published on Monday 11th May in the folder High-Energy Astrophysical Phenomena is “Triaxial magnetars as sources of fast radio bursts” by Jonathan I Katz (Washington University, USA). This paper suggests that the mysterious properties of Fast Radio Bursts (FRB) could be explained by triaxial magnetars, with their activity levels influenced by precessional time scales.
The overlay for this paper is here
You can find the officially accepted version on arXiv here and the announcement on Fediverse here:
https://fediscience.org/@OJ_Astro/116554775791392800
The second paper for this week, published on Tuesday 12th May in the folder Astrophysics of Galaxies, is “The Abundance of Thin Dwarf Galaxies: a Challenge for Cosmological Simulations” by Jose Benavides & Laura V. Sales (UC Riverside, USA), Julio F. Navarro (U. Victoria, Canada), Simon D. M. White (MPA Garching, Germany), and Carlos S. Frenk, Kyle A. Oman & Shaun Cole (U. Durham, UK). Depending on mass up to 40% of galaxies are intrinsically flat, a fraction that numerical models of galaxy formation struggle to reproduce suggesting the models are incomplete.
The overlay for this one is here:
The official version of the paper can be found on arXiv here and the Fediverse announcement here:
https://fediscience.org/@OJ_Astro/116560106342500157
Next one up, the third paper of the week, also published on Tuesday 12th May but in the folder Cosmology and Nongalactic Astrophysics is “Cosmological peculiar velocities in general relativity” by Chris Clarkson (Queen Mary, University of London, UK) and Roy Maartens (U. Western Cape, South Africa). This paper refutes claims that the 1+3 covariant approach to cosmological perturbation theory predicts stronger growth of galaxy peculiar velocities, arguing that standard treatments are correct and fully relativistic.
The overlay for this one is here:
The final, accepted version can be found on arXiv here and the Mastodon announcement is here:
https://fediscience.org/@OJ_Astro/116560224426499932
The fourth paper this week, published on Wednesday May 13th “Possible evidence for a pair-instability supernova nature of ultra-early JWST sources” by Andrea Ferrara & Stefano Carniani (Scuola Normale Superiore, Pisa, Italy), Takahiro Morishita (California Institute of Technology, USA), and Massimo Stiavelli (Space Telescope Science Institute, USA). Published in the section Astrophysics of Galaxies. This paper argues that recent observations challenge early galaxy formation models, suggesting that the bright source, Capotauro, could be a supernova from a massive, metal-free star, not a luminous galaxy as initially thought.
The overlay is here:
The officially accepted version can be found on arXiv here and here is the Mastodon announcement:
https://fediscience.org/@OJ_Astro/116566147448743997
The fifth and final article of this week was also published on Wednesday 13th May but in the folder Cosmology and Nongalactic Astrophysics. The title is “Evolving and interacting dark energy: photometric and spectroscopic synergy with DES Y3 and DESI DR2” and it is by Maria Tsedrik and Benjamin Bose (University of Edinburgh, UK). The study investigates the Dark Scattering interacting dark energy scenario, using data from various sources. Results show no evidence of dark-sector interaction and a preference for the Chevallier-Polarski-Linder parametrisation.
The overlay is here:
You can find the authorized version of this paper on arXiv here and the Fediverse announcement is here:
https://fediscience.org/@OJ_Astro/116566165139100860
And that concludes this week’s update. I’ll do another next Saturday.
#arXiv251211035v3 #arXiv260104953v3 #arXiv260107374v3 #arXiv260314511v2 #AstrophysicsOfGalaxies #Capotauro #ChevallierPolarskiLinder #cosmicShear #cosmologicalSimulations #CosmologyAndNonGalacticAstrophysics #DarkEnergy #DarkEnergySpectroscopicInstrument #DarkEnergySurvey #DarkScattering #DiamondOpenAccess #DiamondOpenAccessPublishing #dwarfGalaxies #fastRadioBursts #galaxyFormation #generalRelativity #HighEnergyAstrophysicalPhenomena #JWST #Magnetars #OpenAccess #OpenAccessPublishing #peculiarVelocities #supernova
The Galilei invariance of classical dynamics does not automatically imply the third Newtonian axiom and the center of mass theorem. For the deduction of these theorems from Galilei invariance we must have, generally, a “kinematical potential” (Helmholtz) and a “potential function” (Clausius), respectively. In celestial mechanics it is possible to have conservation of the motion of the center of gravity but not of the mass center. In this case, the active and the passive masses are different quantities.
Well that takes a load of my mind - I'm glad we got to the bottom of this!
Researchers @ University of Pennsylvania have confirmed that gravity's strength weakens with distance almost exactly as predicted by the equations developed by Newton and later incorporated into Einstein's theory of general relativity. https://phys.org/news/2026-04-gravity-newton-einstein-cosmic-scales.html #Gravity #Newton #Einstein #GeneralRelativity #TheoreticalPhysics #Physics #Astrophysics #Universe #Galaxies #UniversityofPennsylvania
New preprint submitted to Classical and Quantum Gravity:
GR is time-symmetric. That symmetry is the root of singularities, information loss, and the arrow of time.
We propose the opposite: irreversibility is fundamental.
Main result: gravitational collapse halts before any trapped surface forms. C_max < 1. No quantum gravity needed.
General relativity is time-symmetric. This symmetry is the root of its three deepest puzzles: singularities, information loss, and the arrow of time. All existing approaches treat irreversibility as emergent — a statistical mirage atop a reversible microreality. We propose the opposite. Irreversibility is fundamental. It is encoded in a classical scalar field $I$ — the I-field — that couples universally to gravity and matter. Its dynamics are governed by an Euler-Lagrange-Rayleigh action, where a dissipation term $\gamma u^\mu \nabla_\mu I$ breaks time-reversal symmetry at the level of the field equation. The modified Einstein equations introduce a dimensionless stabilization index $\eta$ that quantifies I-field backreaction. The consequences are direct: - Gravitational collapse halts at a finite critical density $\rho_c$, before a trapped surface can form. The maximal compactness satisfies $\mathcal{C}_{\max} < 1$. - No event horizon ever appears — information remains causally accessible throughout the evolution. - The arrow of time emerges from the field dynamics, not from boundary conditions or statistical postulates. Three foundational problems are thus resolved within a single classical framework, from first principles, without invoking quantum gravity.
I developed a new field theory of gravitational collapse — no singularities,
no event horizons, information preserved by construction.
Submitted to EPJC: desk rejected, not read.
Submitted to GRG: rejected after review, zero reviewer comments.
I am an independent researcher. The mathematics does not change
depending on who signs the cover letter.
The paper is publicly available: https://doi.org/10.5281/zenodo.18818991
Genuine criticism welcome.
#physics #generalrelativity #openscience #independentresearch
We introduce the Entropic I-Field Theory, establishing fundamental irreversibility as a new physical principle through an Euler-Lagrange-Rayleigh action formalism. The framework extends Einstein's equations by coupling to a universal scalar field—the I-field—whose dynamics break time-reversal symmetry via an explicit dissipation term $\gamma u^\mu \nabla_\mu I$. The field couples to matter through $\mathcal{J} = \rho/m_I$, where $\rho$ is the energy density and $m_I$ the I-field mass scale, ensuring dimensional consistency. We define the dimensionless **Stabilization Index** $\eta = (g_I^2 m_I/\gamma) \cdot [\lambda I^2/(\lambda I^2 + m_I^2)]$, which quantifies I-field backreaction strength and exhibits natural saturation behavior. Through rigorous analysis of the modified Friedmann equations, we prove that the I-field generates negative pressure $p_I \propto -\rho^2$ at high densities. This pressure opposes gravitational attraction, causing collapse to halt at a critical density $\rho_c$ where the acceleration reverses. The system reaches a finite minimal radius and subsequently re-expands, with maximal compactness $C_{\text{max}} < 1$ that precludes trapped surface formation. The framework provides unified conceptual resolution of three foundational problems: (1) **Singularity avoidance**—gravitational collapse stabilizes at finite radius without horizons or curvature singularities; (2) **Information preservation**—the absence of event horizons ensures all information remains causally accessible; (3) **Arrow of time**—temporal asymmetry emerges from fundamental field dynamics encoded in the dissipation term, rather than from statistical postulates or boundary conditions. The theory satisfies the correspondence principle, smoothly recovering general relativity in the limit $\gamma \to 0$ while preserving all established tests. This work establishes irreversibility as a fundamental rather than emergent feature of gravitational dynamics, extending physics from the time-symmetric framework of "Being" to the irreversible dynamics of "Becoming.
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