Universe MDPI

21/05/2026

🌐 Meet Us at the European Astronomical Society Annual Meeting 2026 (EAS 2026)
📅 Date: 29 June–3 July 2026
📌 Location: Lausanne, Switzerland
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Conference: European Astronomical Society Annual Meeting 2026 (EAS 2026) Date: 29 June–3 July 2026 Location: Lausanne, Switzerland The EAS Annual Meeting...

21/05/2026

Reanalysis of MACHO constraints using Gaia DR3: up to 20% of dark matter could be PBHs. ⚫
If PBHs follow an extended mass function, 100% remains possible. New Milky Way rotation curve changes the game.

The recent astrometric data of hundreds of millions of stars from Gaia DR3 has allowed for a precise determination of the Milky Way rotation curve up to 28 kpc. The data suggest a rapid decline in the density of dark matter beyond 19 kpc. We fit the whole rotation curve with four components (gas, di...

20/05/2026

Axion haloscopes compared: cavity, lumped circuit, and spin‑based detectors. 🧲
This unified review covers signal shapes, noise, and scanning strategies – essential reading for anyone hunting ultralight dark matter.

Axions and axion-like particles are compelling candidates for ultralight bosonic dark matter, forming coherent oscillating fields that can be probed by experiments known as haloscopes. A broad range of haloscope concepts has been developed, including resonant cavity haloscopes, lumped-element circui...

20/05/2026

Starobinsky inflation plus primordial black holes as dark matter – within 1σ of CMB data. 💫

Quantum loop corrections are tiny (

A modified gravity model of Starobinsky inflation and primordial black hole production is proposed in good (within 1σ) agreement with current measurements of the cosmic microwave background radiation. The model is an extension of the singularity-free Appleby–Battye–Starobinsky model by the R4 t...

20/05/2026

Recognising excellence in peer review 🏆

Universe is proud to present the Exceptional Reviewers List 2026. This quarterly programme honours reviewers whose dedication and sharp feedback uphold the quality of our papers. In 2025, 93% of authors rated our peer review as good or excellent. Thank you to all our reviewers! 🙏



Read the full list:

We are thrilled to share the updated Exceptional Reviewers List 2026. This program was established to recognize and honor scholars...

20/05/2026

PeV‑scale SUSY and cosmic strings from F‑term hybrid inflation. 🔬
A B−L extension of the MSSM yields metastable strings compatible with PTA gravitational wave data. SUSY mass scale lands in the PeV region.

We consider F-term hybrid inflation (FHI) and SUSY breaking in the context of a B−L extension of the MSSM that largely respects a global U(1)R symmetry. The hidden sector Kaehler manifold enjoys an enhanced SU(1,1)/U(1) symmetry, with the scalar curvature determined by the achievement of a SUSY-br...

19/05/2026

Next‑gen observatories (EHT, CTA, Rubin) are poised to transform our view of black hole jets. 🚀

This review discusses MADs, GRMHD simulations and how the coming decade will unlock jet formation physics.

Black hole jets represent one of the most extreme manifestations of astrophysical processes, linking accretion physics, relativistic magnetohydrodynamics, and large-scale feedback in galaxies and clusters. Despite decades of observational and theoretical work, the mechanisms governing jet launching,...

19/05/2026

The H₀ tension refuses to go away. This critical review weighs early vs. late universe measurements and suggests look‑back time as a key angle. 🔭

Can new physics or alternative methods finally resolve it?

A critical discussion on the H0 Hubble constant tension is presented by considering both early and late-type observations. From recent precise measurements, discrepancies emerge when comparing results for some cosmological quantities obtained at different redshifts. We highlight the most relevant me...

19/05/2026

We are pleased to announce the winners of the Universe 2024–2025 Most Popular Cover Selection. 🏆
Four outstanding papers have been chosen, including research on FRBs, compact objects, the Crab supernova, and AI in astronomy. Each winner receives CHF 800 and a certificate. Congratulations to all!

Full announcement: https://www.mdpi.com/about/announcements/15930

19/05/2026

A single‑parameter dark energy model that deviates from ΛCDM – and might ease the H₀ tension. 📈
New analysis finds η nonzero, with a future deceleration phase. Statefinder confirms late‑time departure from standard cosmology.

We propose a novel dark-energy equation-of-state parametrization, with a single parameter η that quantifies the deviation from ΛCDM cosmology. We first confront the scenario with various datasets, from the Hubble function (OHD), Pantheon, baryon acoustic oscillations (BAO), and their joint observa...