Explore cosmic expansion and the Hubble constant, uncovering how our universe grows and the mysteries behind its accelerating pace.

The image of an extremely rare supernova could solve the mystery of the expansion rate of the universe.

Is it possible to understand the universe without understanding the largest structures that reside in it? In principle, not likely. In practical terms? Definitely not. Extremely large objects can dist...

Researchers in Munich have used the Large Binocular Telescope in Arizona to capture five images of one and the same supernova in a single picture. The gravity of two foreground galaxies has deflected the light from a supernova far in the background along different paths to Earth.

The research team inferred properties of dark energy and concluded that it might change and evolve over time.

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“Embrace cosmic expansion and radiant self-expression” ~Crystal Wind Read Time: 8 min | 

READ TIME: 12 min “Discover why assertive power drives fated awakenings this June” ~Crystal Wind

The universe is expanding. But how do we know that?

A study has challenged the common conception that the universe’s expansion is accelerating, supporting the idea that reality could one day end in a ‘big crunch’

New measurements show that the expansion rate of the universe is faster than can be explained by our current understanding of physics.

NASA’s Nancy Grace Roman Space Telescope will be a discovery machine, thanks to its wide field of view and resulting torrent of data. Scheduled to launch no later than May 2027, with the team working...

Discover what dark energy is, why it makes up 69% of the universe, and how scientists study this mysterious force driving cosmic expansion.

A new study proposes that the accelerating expansion of the universe might not require dark energy but instead emerge from quantum modifications to spacetime geometry. Physicist Savvas Koushiappas from Brown University suggests that cosmic acceleration could be a macroscopic imprint of quantum uncertainty in simultaneously knowing the universe's size and expansion rate. This theory, published in Physical Review D, challenges the standard cosmological model by linking dark energy observations to quantum gravity effects at the cosmological horizon. The research implies that the universe's expansion history might reflect irreducible quantum uncertainties rather than an unknown component like dark energy. Koushiappas also proposes a bouncing universe model that avoids the Big Bang singularity, though inconsistencies remain. Observations from projects like DESI and Euclid could test these ideas, potentially redefining our understanding of cosmic evolution. The study highlights ongoing efforts to unify general relativity with quantum mechanics, addressing one of physics' greatest unsolved problems.

The article explains how the universe's expansion allows distant galaxies to recede faster than the speed of light without violating Einstein's theory of relativity. Cosmic expansion causes space itself to stretch, enabling galaxies to move apart at velocities exceeding light speed. This phenomenon occurs because the expansion of space is not limited by the local speed of light restriction. Light from distant galaxies takes billions of years to reach us, and during this time, the universe continues to expand. The observable universe's edge, known as the particle horizon, is about 45 billion light-years away, despite the universe being only 13.77 billion years old. Dark energy accelerates this expansion, eventually pushing galaxies beyond our Local Group out of sight. In about 100 billion years, the universe will appear almost empty as light from distant galaxies becomes stretched beyond detectable wavelengths. The article emphasizes that while galaxies may recede faster than light, this does not violate relativity because the expansion of space itself is not constrained by the speed of light. The Hubble distance marks the point where galaxies begin receding faster than light, while the cosmological event horizon defines the ultimate limit of observable light. These concepts highlight the complex interplay between cosmic expansion, dark energy, and the observable universe's future evolution.

The article explains the apparent paradox of the universe's size versus its age by highlighting the role of cosmic expansion. Despite being only 13.8 billion years old, the observable universe spans 93 billion light-years due to the continuous expansion of space. Light from distant galaxies has traveled for billions of years, but the universe's expansion has stretched the space between galaxies, making the observable universe much larger than its age suggests. The explanation involves concepts like the cosmic microwave background, the Hubble sphere, and the distinction between light travel time and present-day distance. Cosmologists calculate the observable universe's size by integrating the distance light can cover while accounting for the changing scale factor of the universe. Parameters such as the expansion rate and dark energy proportions influence these calculations. The article clarifies that ancient photons have crossed a changing geometry, with their journey lasting nearly 13.8 billion years while the present distance between endpoints grew to about 46 billion light-years. This understanding underscores the dynamic nature of the universe and how its expansion affects our perception of cosmic distances.

New time-delay cosmography data from TDCOSMO deepens the Hubble tension mystery. Discover what lensed quasars reveal about cosmic expansion. Read now!

By Marcel Acunya — May 2025

This work proposes a unified theoretical framework in which time is modeled as a non-propagating scalar field τ(x^μ), defining the structural substrate of spacetime. Unlike conventional formulations, ...

This document provides a formal canonical quantization of the structural time field under the Hamiltonian constraint. It complements the primary proposal available at 10.5281/zenodo.15496759, focusing...