The article explains what it means for objects to be gravitationally bound in an expanding universe, discussing how structures like stars, galaxies, and clusters are held together by gravity despite the universe's overall expansion, and explores how dark energy influences the future of these structures.
Launched on December 25, 2021, the James Webb Space Telescope has significantly advanced our understanding of the universe by capturing detailed images of the early cosmos, confirming existing theories, and raising new questions about cosmic evolution, exoplanets, and black holes, despite initial delays and budget overruns.
NASA's Nancy Grace Roman Space Telescope will map thousands of cosmic voids to better understand the universe's expansion and the nature of dark energy by observing the distribution and shapes of these vast, sparsely populated regions, which can reveal key insights into the universe's composition and evolution.
Originally Published 2 months ago — by Hacker News
A recent study suggests that the universe's expansion is slowing down rather than accelerating, challenging the standard cosmological model and implying potential new physics or models like a cyclic universe. The findings focus on the impact of progenitor star age on Type Ia supernova luminosity, which could bias previous measurements of cosmic expansion. While intriguing, the results are met with cautious skepticism and require further validation with upcoming data.
New research suggests that the universe's expansion may be slowing down and dark energy might not be accelerating it anymore, potentially marking a major shift in cosmological understanding. This conclusion is based on findings that challenge the standard model of dark energy, indicating the universe has already entered a phase of decelerated expansion, with future observations from the Vera C. Rubin Observatory expected to further test these results.
A new study suggests that the universe's expansion is slowing down rather than accelerating, challenging the long-held belief that dark energy is causing an ever-increasing expansion rate. The findings indicate that dark energy may weaken over time, leading to a transition from acceleration to deceleration, which could significantly alter our understanding of the universe's past and future.
Recent cosmological research suggests that understanding the universe's ultimate fate—whether it will end in a Big Crunch, Big Freeze, or a cyclical Big Bounce—could provide insights into what preceded the Big Bang, especially with new evidence indicating that dark energy may not be constant but evolving over time, possibly involving particles called axions that influence cosmic expansion.
Recent observations suggest dark energy may be weakening, which could imply a potential, though currently unlikely, future scenario of a Big Crunch, but the evidence is not yet conclusive and further data is needed to determine the universe's ultimate fate.
A new study proposes that the universe's accelerating expansion can be explained by a modified geometry of spacetime, called Finsler geometry, without invoking dark energy, by allowing measurements to depend on direction and velocity, which could reshape our understanding of cosmic dynamics.
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.
Recent research suggests that dark energy, which drives the universe's accelerated expansion, may be evolving over time rather than remaining constant, implying the existence of a new, ultra-light particle and potentially altering our understanding of the universe's future.
Using gravitational wave detectors LIGO, Virgo, and KAGRA, scientists have identified a 'stellar graveyard' filled with mergers of black holes and neutron stars, including the heaviest black holes observed to date, which enhances understanding of stellar evolution and the universe's expansion rate. The data also tests Einstein's theory of gravity and improves measurement of the Hubble Constant.
Astronomers suggest Earth and our galaxy may reside in a giant cosmic void, which could explain discrepancies in measurements of the universe's expansion rate, potentially solving the long-standing Hubble tension, though this idea remains controversial within the scientific community.
Recent research suggests we may live in a large cosmic void with fewer galaxies, which could explain the faster-than-expected expansion rate of the universe known as the Hubble tension. The study uses baryon acoustic oscillations to support the void hypothesis, indicating that our local universe might be expanding more quickly due to residing in a low-density region, challenging the standard cosmological model.
Recent evidence suggests that dark energy, previously thought to be a constant, may actually be evolving over time, but the data is still inconclusive and interpretations vary among scientists. The debate revolves around whether dark energy is changing, which could impact our understanding of the universe's expansion, or if current measurement discrepancies are due to errors or biases. Future missions are expected to clarify whether dark energy is indeed dynamic or remains a cosmological constant.