Tag

Hubble Tension

All articles tagged with #hubble tension

science1 day ago•4 min saved

Cosmic Expansion Gap Grows: Dark Energy May Be Evolving

Two long-standing methods for measuring the universe’s expansion—early-universe data from Planck and local observations of supernovae—remain at odds, a discrepancy known as the Hubble tension. New DESI results, when combined with other probes, hint that dark energy might not be a constant after all, challenging the simplest ΛCDM model. Riess and Leauthaud have warned that the standard cosmology could be cracking, even as some newer analyses (e.g., Lyman-alpha forest data) either align with or complicate this evolving picture. The cosmos’ expansion history thus remains an active, debated frontier.

via All That's Interesting|

#cosmology #dark-energy #desi

science3 days ago•12 min saved

The Fossil Light That Unlocked the Universe's Dawn

An accessible guide to the cosmic microwave background: the fossil light from 380,000 years after the Big Bang that made the universe transparent, now observed as a 2.7 K microwave map by COBE, WMAP, and Planck; its tiny fluctuations seed galaxies, constrain curvature and matter content, and even highlight the current tension in the measured Hubble constant, reminding us that the cosmos still has mysteries to unveil.

via Daily Kos|

#cosmic-microwave-background #early-universe #hubble-tension

space3 days ago•45 min saved

Cosmic Glitch Suggests Gravity Fades at the Universe’s Largest Scales

Researchers from the University of Waterloo and University of British Columbia propose a minimal modification to gravity—a 'cosmic glitch'—where gravity is about 1% weaker on cosmological scales (billions of light-years) than predicted by general relativity, captured by the parameter Ωg. Analyses of Planck 2018 data yield Ωg ≈ -0.0087 ± 0.0046 and a Hubble constant near 68.6 km/s/Mpc; in some data combinations this can lessen the Hubble tension, but the improvement isn't universal across all datasets. The model preserves GR on smaller scales and could be tested by future CMB and large-scale structure surveys (DESI, Euclid). If confirmed, it would hint at physics beyond general relativity at cosmic distances.

via The Brighter Side of News|

#cosmic-glitch-in-gravity #general-relativity #gravity

space-and-astronomy25 days ago•51 min saved

Cosmic Acceleration May Be an Illusion, Cosmology Faces a Fresh Challenge

New analysis of Type Ia supernovae data, with progenitor-age corrections from the Pantheon+ catalog, suggests the universe’s expansion may be mildly anisotropic and not accelerating uniformly in all directions. If younger supernova progenitors are fainter after standardization, distant observations could mimic acceleration, meaning the apparent cosmic acceleration could be a local, directional effect tied to our motion through the cosmos. This challenges the isotropy assumed in ΛCDM and raises doubts about dark energy's role, while also intersecting with the ongoing Hubble tension between local and early-universe expansion rates.

via Yahoo|

#anisotropy #dark-energy #hubble-tension

science-cosmology28 days ago•2 min saved

Ancient stars align with the older universe age, challenging younger estimates

A study analyzing about 250,000 old Milky Way stars using Gaia and LAMOST data finds the oldest stars to be about 13.73 billion years old, aligning with the 13.8‑billion‑year age inferred from the cosmic microwave background and weakening the case for the younger 12.5–12.9 billion-year age suggested by supernova measurements; the Hubble tension persists without this stellar-age result resolving it.

via Futura, le média qui explore le monde|

#age-of-the-universe #gaia #hubble-tension

science1 month ago•3 min saved

Ancient Milky Way Stars Lock in the Universe's True Age

A team analyzed 247,103 Milky Way stars with LAMOST spectroscopy and Gaia distances, focusing on old, metal-poor stars. After stringent quality checks, 155,600 stars yielded an oldest-star age of about 13.73 billion years, implying a cosmic age of roughly 13.8 billion years that matches Planck CMB estimates and casts doubt on early-universe new-physics solutions to the Hubble tension.

via Universe Today|

#cosmology #hubble-tension #milky-way

science1 month ago•4 min saved

Neutron-Star Merger Brings Fresh Data to the Universe's Expansion Rate

An international team combined gravitational-wave data from a neutron-star collision with telescope and astrometric observations to measure the Hubble-Lemaitre Constant via the Cosmic Distance Ladder. Their result adds a late-Universe, gravitational-wave–based data point that loosely aligns with early-Universe (CMB) estimates, highlighting GW methods as a valuable but still less precise tool to help resolve the Hubble tension. More neutron-star mergers are needed to confirm the implications for cosmology.

via Universe Today|

#cosmic-distance-ladder #gravitational-waves #hubble-constant

science3 months ago•10 min saved

Cosmic Voids: The Universe’s Quiet Labs for Big Questions

Cosmic voids—vast, underdense regions in the cosmic web—are becoming powerful cosmological laboratories for gravity, dark energy, and the Hubble tension. New surveys like DESI and Euclid will map tens of thousands to over 100,000 voids with high fidelity, while advanced simulations fill in their evolution. By tracing how galaxies and other tracers move through voids, scientists test gravity theories, study neutrinos, and sharpen our understanding of dark energy. Some researchers even speculate we may live in a colossal supervoid that could help explain the slightly faster local expansion rate, the Hubble tension. The next decade should decisively test these ideas and deepen our view of the universe.

via WIRED|

#cosmic-voids #cosmology #dark-energy

science4 months ago•3 min saved

New Hubble Constant Precision Keeps Cosmology in Tension

An international team reports the most precise measurement of the Hubble constant to date (about 73.5 km/s/Mpc with ~1% accuracy). While tighter, the result reinforces the long-standing Hubble tension between local measurements and the standard cosmological model, raising the possibility of undiscovered physics or systematic issues and underscoring the need to reassess our understanding of the universe’s expansion.

via Futurism|

#astrophysics #cosmology #hubble-constant

space4 months ago•70 min saved

New Local Distance Network reinforces the Hubble tension, challenging standard cosmology

Space scientists assembled decades of local-universe distance measurements into the Local Distance Network, delivering the most precise direct measure of the Hubble constant to date (73.50 km/s/Mpc with ~1.1% uncertainty) and confirming the ongoing discrepancy between early- and late-universe expansion rates. By anchoring many distance indicators—from parallax stars and megamasers to Cepheids and thousands of galaxies—the study shows the Hubble tension persists, suggesting the standard cosmological model may be incomplete and could point to new physics, with future observatories potentially resolving the difference.

via Live Science|

#cosmology #distance-ladder #hubble-constant

science4 months ago•6 min saved

Unified Measure of Cosmic Expansion Deepens Hubble Mystery

A study in Astronomy & Astrophysics presents the most precise combined value for the Hubble constant, about 73.5 km/s/Mpc (≈45.7 miles/s/Mpc), derived from a new distance-network framework that unifies multiple distance indicators. While it clarifies the measurement, the result reinforces the Hubble tension and suggests that cosmology may require new physics or revisions to current models.

via The Daily Galaxy|

#astronomy-and-astrophysics #cosmology #distance-indicators

space-and-spaceflight4 months ago•17 min saved

Unified Framework Tightens Hubble Constant, Keeps the Tension Alive

Astronomers developed a community-built, open-source distance network that merges local-universe distance measurements to produce a precise Hubble constant of 73.50 ± 0.81 km/s/Mpc. The result confirms, rather than resolves, the existing discrepancy with early-Universe measurements, reinforcing the Hubble tension and hinting at new physics beyond the standard cosmological model. The framework is designed for future testing with next-generation telescopes.

via Gizmodo|

#cosmology #dark-energy #distance-ladder

science4 months ago•7 min saved

Precise local expansion rate deepens the Hubble tension and hints at new physics

An international effort builds a highly precise local measurement of the Hubble constant (73.50 ± 0.81 km/s/Mpc), reinforcing the discrepancy with early-Universe predictions (~67–68) and strengthening the case that the Hubble tension may point to new physics beyond the standard cosmological model.

via ScienceDaily|

#cosmology #dark-energy #distance-ladder

science5 months ago•6 min saved

Cosmic Gravitational-Wave Hum Tightens the Hubble Constant Bounds

A new method uses the faint gravitational-wave background from unresolved distant black hole mergers—the stochastic siren—to constrain the Hubble constant. By linking merger rates to the observable universe’s size, a stronger background would indicate slower expansion; non-detections thus tighten limits, and when combined with data from individually observed mergers, the approach yields a more precise H0. With future, more sensitive detectors the gravitational-wave background could be detected and used to further refine cosmological measurements, potentially helping resolve the Hubble tension.

via SciTechDaily|

#cosmology #gravitational-waves #hubble-constant

astronomy5 months ago•57 min saved

Cosmic expansion could be measured by the universe's gravitational hum

Scientists propose using the stochastic gravitational-wave background—the faint, background hum from countless distant mergers—to measure the Hubble constant, offering an independent, multi‑messenger approach that could help resolve the long‑standing Hubble tension as gravitational‑wave detectors grow more sensitive.

via Space|

#astronomy #gravitational-waves #hubble-constant