All articles tagged with #hubble constant
Researchers at the University of Tokyo have used a new method involving gravitational lensing to measure the universe's expansion rate, providing evidence that the discrepancy known as the Hubble tension is likely due to real physics rather than measurement errors, with their findings aligning with current local measurements rather than early universe estimates.
An international team has demonstrated that pixelized strong-lensing modeling on galaxy clusters significantly improves the precision of measuring the Hubble constant, potentially resolving the existing tension in its current measurements and advancing high-precision cosmology.
Jim Baggott's book 'Discordance' explores the ongoing challenges and uncertainties in understanding the universe, focusing on the Hubble constant and the discrepancies in cosmological measurements, highlighting that modern cosmology remains an unfinished and evolving science.
The rare 'Einstein zig-zag' gravitational lens system, involving six images of a distant quasar created by two aligned galaxies, offers a unique opportunity to refine measurements of the universe's expansion rate and dark energy, potentially resolving current cosmological tensions and deepening our understanding of the universe's fundamental forces.
Using data from the James Webb Space Telescope, scientists have refined the measurement of the universe's expansion rate, finding it consistent with the standard cosmological model and potentially resolving a long-standing debate about the Hubble constant.
The Big Bang Theory, often misunderstood as an explosive event, actually describes the rapid expansion of the universe from a hot, dense state. It didn't occur at a specific point in space but happened everywhere simultaneously. The theory explains the visible universe's expansion but not the conditions before or the cause of the expansion. Cosmic inflation, a brief period of rapid expansion, is a key part of this narrative. Despite some discrepancies in the expansion rate, known as the Hubble tension, the Big Bang Theory remains a cornerstone of cosmology.
New data from the James Webb Space Telescope confirms previous Hubble Space Telescope measurements of the Universe's expansion rate, suggesting discrepancies with theoretical models may indicate new physics. The study, published in The Astrophysical Journal, supports the accuracy of Hubble's data, ruling out measurement errors and highlighting a tension between observed expansion rates and predictions from the standard LambdaCDM model. Theorists are now exploring explanations such as early dark energy or exotic particles to resolve this "Hubble tension."
Astronomers using the James Webb Space Telescope have discovered the first 'Einstein zig-zag,' a rare gravitational lensing phenomenon where a quasar appears six times in a single image. This unique alignment, involving two galaxies and a quasar, could help address major cosmological mysteries, such as the nature of dark energy and the Hubble constant discrepancy. The discovery offers a promising method to refine measurements of these parameters, potentially resolving the 'Hubble tension' in cosmology.
The James Webb Space Telescope (JWST) has confirmed the Hubble Space Telescope's (HST) measurements of the Hubble Constant, a key parameter in cosmology that defines the universe's expansion rate. A study led by Adam G. Riess used JWST to validate HST's results using the cepheid/supernova distance ladder, achieving a Hubble Constant value of 72.6 ± 2.0 km/s/Mpc, closely aligning with HST's 72.8 km/s/Mpc. This cross-verification helps refine the accuracy of the constant, crucial for understanding the universe's age, size, and fate.
Researchers have identified a unique gravitational lens system, J1721+8842, where light zigzags through two aligned galaxies, termed the 'Einstein zig-zag.' This discovery, supported by data from the Nordic Optical Telescope and the James Webb Space Telescope, could provide new insights into the universe's expansion and help resolve the Hubble tension, a discrepancy in measuring the universe's expansion rate.
The Hubble constant, which describes the rate of the Universe's expansion, is not truly constant over time. While it appears constant to us at a given moment, it changes as the Universe evolves due to the presence of different forms of energy, such as dark energy. The expansion rate drops as the Universe grows, with the Hubble constant asymptoting to a finite, positive value determined by dark energy density. Although individual objects appear to accelerate away from us, the expansion rate itself is still decreasing. This challenges the idea of a constant expansion and highlights the complex nature of the Universe's evolution.
A new 3D map of the Universe has provided a precise measurement of the Hubble constant, narrowing it down to 67.97 kilometers per second per megaparsec. This measurement, based on "bubbles" created by the expanding early Universe, deepens the ongoing crisis in cosmology due to the discrepancy between results obtained using standard candles and standard rulers. The new data from the Lawrence Berkeley National Laboratory's Dark Energy Spectroscopic Instrument suggests that the Hubble constant may be lower than previously thought, possibly indicating the need for new physics to explain the expansion of the Universe. The results also reveal subtle deviations from the current model of the Universe, providing an opportunity to test the nature of dark energy.
Astronomers are exploring new methods to measure the expansion of the Universe, aiming to resolve the Hubble tension. A recent paper introduces a technique that utilizes red giant stars at the "Tip-of-the-Red-Giant-Branch" (TRGB) phase, leveraging their brightness fluctuations to improve distance measurements. While this method enhances confidence in expansion measurements, it may not fully resolve the discrepancy in Hubble constant values. Nevertheless, refining these measurements could unveil new insights into the fundamental workings of the Universe.
Astronomers have long been fascinated by measuring cosmic distances, with the Hubble constant at the center of this quest, representing the speed at which a galaxy would move away from us if it were 1 megaparsec distant.
A study published in The Astrophysical Journal Letters by EPFL professor Richard I. Anderson and colleagues refines cosmic distance measurements using the acoustic oscillations of red giant stars, offering a more nuanced approach to measuring distances across the universe. By analyzing data from the Large Magellanic Cloud, the researchers found that the brightness fluctuations of red giants allow for distinguishing stars by age, crucial for highly accurate distance measurements required for cosmology and for obtaining the best map of the local universe. This refinement may lead to groundbreaking new insights into the basic physical processes that decide how the universe evolves.