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Distance Ladder

All articles tagged with #distance ladder

Harvard’s human computer unlocked the universe’s scale
science1 month ago

Harvard’s human computer unlocked the universe’s scale

Henrietta Leavitt, a Harvard College Observatory 'human computer' paid a pittance, discovered the period-luminosity relation for Cepheid variables, enabling the cosmic distance ladder used to measure faraway galaxies. By linking a Cepheid’s pulsation period to its true brightness, Leavitt laid the groundwork for determining distances, anchoring the scale of the universe and underpinning Hubble’s finding that Andromeda is a separate galaxy. Modern analyses continue to refine and reassess her method, keeping Leavitt’s contribution central to cosmology.

via Space Daily|
#andromeda-galaxy#cepheid-variables#distance-ladder
New Local Distance Network reinforces the Hubble tension, challenging standard cosmology
space2 months ago

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
Unified Framework Tightens Hubble Constant, Keeps the Tension Alive
space-and-spaceflight2 months ago

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
"New Measurements Fail to Resolve Hubble Tension"
science2 years ago

"New Measurements Fail to Resolve Hubble Tension"

The Hubble tension, a significant discrepancy in measuring the universe's expansion rate, remains unresolved despite new measurements. The early relic method suggests an expansion rate of ~67 km/s/Mpc, while the distance ladder method indicates ~73 km/s/Mpc. Recent claims of an intermediate value (~70-71 km/s/Mpc) are dismissed due to their high uncertainty. The precision of the parallax-Cepheid-supernova distance ladder method is unmatched, and until other methods achieve similar precision, the Hubble tension will persist.

via Big Think|
#cosmology#distance-ladder#early-relic-method