Results 131 to 140 of about 4,402,515 (251)

Is Dark Energy Changing? Probing the Universe’s Expansion with Present and Future Astronomical Probes

The Astrophysical Journal
This study explores the possibility of a time-varying dark energy (DE) equation of state (EoS) deviating from −1. We employ a comprehensive data set of the usual astronomical probes (Type Ia supernovae, baryon acoustic oscillations, Big Bang ...
Mehdi Rezaei, Supriya Pan, Weiqiang Yang, David F. Mota   +3 more
doaj   +1 more source

Modeling Kinetic Reconnection Onset in Global Magnetospheric Simulations

Journal of Geophysical Research: Space Physics, Volume 131, Issue 9, September 2026.
Abstract We investigate the onset of magnetic reconnection in Earth's magnetotail using a coupled magnetohydrodynamic with embedded particle‐in‐cell (MHD‐EPIC) model, which self‐consistently links global magnetospheric dynamics to electron‐scale kinetic processes. Unlike standalone kinetic simulations with idealized boundary conditions, reconnection in
Talha Arshad, Yuxi Chen, Gabor Toth
wiley   +1 more source

Spacetime Foam and the Cosmological Constant

, 2007
In the saddle point approximation, the Euclidean path integral for quantum gravity closely resembles a thermodynamic partition function, with the cosmological constant playing the role of temperature and the "density of topologies" acting as an
The Cosmological Constant, S. Carlip, Carlip Department   +2 more
core  

Beyond Two Parameters: Revisiting Dark Energy with the Latest Cosmic Probes

The Astrophysical Journal
Dark energy (DE) models with many free parameters are often considered excessive, as constraining all parameters poses a significant challenge. While such models offer greater flexibility to probe the DE sector in more detail.
Hanyu Cheng, Supriya Pan, Eleonora Di Valentino   +2 more
doaj   +1 more source

A Magnetospheric Source for Near‐Planet Whistler‐Mode Waves at Venus

Journal of Geophysical Research: Space Physics, Volume 131, Issue 9, September 2026.
Abstract The presence or absence of lightning in the atmosphere of Venus has important implications for atmospheric chemistry, potential chemical signatures of life, identifying volcanic activity, and quantifying potential hazards to future exploration missions.
David M. Malaspina, Keirra D. Kernan, Katherine A. Goodrich, Yingjuan Ma, Shannon M. Curry   +4 more
wiley   +1 more source

Mapping the Λ_sCDM Scenario to f(T) Modified Gravity: Effects on Structure Growth Rate

Universe
The concept of a rapidly sign-switching cosmological constant, interpreted as a mirror AdS-dS transition in the late universe and known as the ΛsCDM, has significantly improved the fit to observational data, offering a promising framework for alleviating
Mateus S. Souza, Ana M. Barcelos, Rafael C. Nunes, Özgür Akarsu, Suresh Kumar   +4 more
doaj   +1 more source

Present‐Day Kinematics of Continental Greece and Balkans Revealed by Sentinel‐1 InSAR Data

Journal of Geophysical Research: Solid Earth, Volume 131, Issue 9, September 2026.
Abstract The Balkan Peninsula hosts the highest seismic activity in Europe, marked by numerous Mw6+ earthquakes in diverse tectonic settings. Assessing tectonic surface deformation is crucial to understand the forces controlling kinematics and, ultimately, constraining geodynamic models. However, because measuring slow velocity rates (a few mm/yr) with
A. Meridi, M. Métois, C. Lasserre, M.‐P. Doin, P. Durand   +4 more
wiley   +1 more source

Probing for cosmological parameters with LAMOST measurement

, 2008
In this paper we study the sensitivity of the Large Sky Area MultiObject Fiber Spectroscopic Telescope (LAMOST) project for the determination of cosmological parameters, employing the Monte Carlo Markov chains method. For comparison, we first analyze the
Li, Hong, Fan, Zuhui, Xia, Jun-Qing, Zhang, Xinmin   +3 more
core   +1 more source

Variation of Venusian Gravity Wave Absolute Momentum Fluxes and Drag as Retrieved From the Akatsuki Mission

Journal of Geophysical Research: Planets, Volume 131, Issue 9, September 2026.
Abstract Using temperature retrievals from Akatsuki radio occultation measurements, we characterize gravity wave activity as a function of vertical wavenumber and altitude. For the first time, we estimate the absolute horizontal momentum fluxes and the magnitude of the gravity wave drag (i.e., wave acceleration), assuming a horizontal wavelength of 300 
Erdal Yiğit, Emilia Sloan
wiley   +1 more source

Hints of New Physics for the Hubble Tension: Violation of Cosmological Principle

The Astrophysical Journal Letters
Discrepancy between the measurements of Hubble constant H _0 from the cosmic microwave background and the local distance ladder is the most serious challenge to the standard ΛCDM model.
J. P. Hu, X. D. Jia, J. Hu, F. Y. Wang
doaj   +1 more source