All articles tagged with #cosmology
NASA’s Nancy Grace Roman Space Telescope will survey vast areas of the infrared sky, acting as a wide-field scout that finds targets for Hubble and Webb, maps the distribution of galaxies to test cosmology, and demonstrates coronagraphy for direct imaging of exoplanets, all while informing future missions like Habitable Worlds Observatory.
New computer simulations show that the conversion of dark photons to ordinary photons in the early universe may not heat the cosmos as much as previously thought, reopening expanded parameter space for dark photon dark matter and potentially guiding new experimental searches.
Physicist Melvin Vopson argues that information is as fundamental as mass and energy and that gravity emerges as a data‑compression, entropy‑minimizing process; the theory, which recovers Newton’s law from information dynamics, challenges the need for dark matter and dark energy and points to a computation-like optimization at the heart of the cosmos.
Physicist Savvas Koushiappas suggests the Universe’s accelerating expansion could arise from a quantum modification to cosmic geometry at the cosmological horizon, meaning dark energy might be replaced by a macroscopic imprint of quantum gravity. By tying the uncertainty in simultaneously knowing the Universe’s size and expansion rate to altered expansion equations, the model could explain acceleration and even allow a bouncing origin instead of a Big Bang, though it leaves several questions unresolved. Future data from DESI, Euclid, and the Vera Rubin Observatory could test these ideas and refine our understanding of cosmic expansion.
A new Physical Review D paper by Savvas Koushiappas suggests the Universe’s accelerating expansion may arise from a macroscopic quantum uncertainty in simultaneously knowing the Universe’s size and expansion rate, effectively tying cosmic acceleration to quantum gravity at the cosmological horizon rather than to dark energy. The model can modify the expansion history and even allow a Big Bang replacement by a bounce in some configurations. Observations from DESI, Euclid, and the Vera C. Rubin Observatory could test these ideas, but the proposal remains speculative with open questions about consistency and interpretation.
Physicists have rebuilt fluid dynamics from the ground up with an effective field theory based on fundamental symmetries, showing the Navier–Stokes equations are emergent rather than exact and connecting fluids to cosmology, black holes, and exotic states to predict new behaviors and refine heat diffusion.
A new analysis of three radio-sky surveys finds a stronger radio dipole than predicted by the cosmic microwave background, implying the solar system’s motion could be about 828,000 km/h (515,000 mph)—roughly four times faster than standard estimates. The discrepancy could reflect either a true velocity anomaly or large-scale asymmetry in matter distribution; upcoming Square Kilometre Array observations (starting 2027) should help distinguish between these possibilities.
Southampton researchers re-analyze a 2025 Yonsei claim that the universe’s expansion isn’t accelerating and find the result was a false alarm. After correcting for galaxy-mass calibration and local stellar ages in Type Ia supernovae, the data remain consistent with an accelerating universe and dark energy remains needed. The Yonsei team still argues age effects matter in some analyses, but the broader cosmology community will gain more decisive data from upcoming surveys like the Vera Rubin Observatory to settle the issue.
Astronomers using the James Webb Space Telescope have identified MoM-BH*-1, a rare hybrid object that blends a star-like gas cloud with a black hole about 100,000 solar masses. It emits energy far exceeding typical stellar formations and is about 100 billion times brighter than the average star, even outshining its host galaxy. This “black-hole star” could explain the little red dots seen in JWST images from the dawn of the universe and may shed light on how the first cosmic structures formed; researchers will continue studying its size and atmospheric composition with JWST starting in December.
An international team released the largest 2D map of the universe, charting about 4 billion objects across three-quarters of the sky, using 13 years of data from the DESI Legacy Imaging Surveys and observations from the Dark Energy Camera (Blanco 4m), Mayall 4m, and Bok 2.3m telescopes, with data supplemented by WISE. The high‑resolution map spans visible and near‑infrared light and will guide future observatories, helping researchers find gravitational lenses, supernovae and dark‑matter/dark‑energy phenomena while informing projects like the Vera C. Rubin Observatory and the Nancy Grace Roman Space Telescope.
Astronomers using the DESI Legacy Imaging Surveys have released the largest 2D map of the universe to date — a 5.6‑trillion‑pixel panorama spanning roughly three‑quarters of the sky and detailing nearly four billion celestial objects. Built from more than 263,000 telescope exposures over a decade and covering visible to near‑infrared wavelengths, the map provides the 2D foundation for DESI’s much larger 3D cosmic map and will aid dark‑energy studies, galaxy evolution research, and training AI systems for future observatories.
British physicist Stephen Hawking, famed for Hawking radiation and popularizing cosmology and black hole physics, died in 2018 after living for decades with ALS. The article traces his career from Cambridge's Lucasian Professorship to bestselling works like A Brief History of Time, his pop culture presence, and the enduring message that life is brief but collective scientific progress can illuminate the universe.
Imagine life arising 1–2 billion years after the Big Bang: the night sky would be busier and bluer, with denser star formation and brighter, closer nebulae in smaller, gas-rich galaxies. An observer 1 Gyr after the Big Bang would see about 5,000–8,000 stars at once and 10,000–15,000 over a full night; at 2 Gyr, roughly 15,000–30,000 at once and 30,000–60,000 over a night—like using binoculars instead of the naked eye. The cosmic microwave background would be hotter (11–18 K), and the universe would be smaller and denser, shortening distances to galaxies and making extragalactic observations easier but more foreground-laden. Dark matter would dominate and dark energy would be minor; whether intelligent life would arise remains uncertain, and no alien civilizations are detected today.
A sweeping, decade-spanning tour of 20 landmark cosmic discoveries—from early parallax and Neptune’s discovery to the emergence of dark energy and gravitational-wave astronomy—showing how each breakthrough reshaped our understanding of the universe and spurred new questions.
Physicist Ginestra Bianconi proposes Gravity from Entropy (GfE), a quantum gravity framework in which gravity arises from an information-theoretic tension between two spacetime metrics. They find total entropy increases with cosmic expansion while entropy per unit volume falls, allowing local structure to form even as the universe trends toward disorder. GfE reduces to General Relativity at low energies but includes a dynamical dark-energy term that could yield observable effects, offering a potential bridge between gravity, thermodynamics, and quantum theory.