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Category: cosmology – Page 52

We revise the dynamics of interacting vector-like dark energy, a theoretical framework proposed to explain the accelerated expansion of the universe. By investigating the interaction between vector-like dark energy and dark matter, we analyze its effects on the cosmic expansion history and the thermodynamics of the accelerating universe. Our results demonstrate that the presence of interaction significantly influences the evolution of vector-like dark energy, leading to distinct features in its equation of state and energy density. We compare our findings with observational data and highlight the importance of considering interactions in future cosmological studies.

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New James Webb Space Telescope observations may have done with one of the longest-standing tensions in cosmology.

For almost a decade, astronomers have been struggling with a nagging mismatch between two different ways of determining the Hubble constant — a measure of the current expansion rate of the universe. This mismatch, known as the Hubble tension, has led to claims that new physics might be needed to solve the issue. (Read about the “constant controversy” in the June 2019 issue of Sky & Telescope.)

But a detailed analysis of a new set of James Webb Space Telescope (JWST) observations now suggests that the problem may not exist. “As Carl Sagan said, extraordinary claims require extraordinary evidence,” says Wendy Freedman (University of Chicago), “and I don’t see extraordinary evidence.”

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Dark matter is the invisible force holding the universe together—or so we think. It makes up about 85% of all matter and around 27% of the universe’s contents, but since we can’t see it directly, we have to study its gravitational effects on galaxies and other cosmic structures. Despite decades of research, the true nature of dark matter remains one of science’s most elusive questions.

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Proposed experiments will search for signs that spacetime is quantum and can exist in a superposition of multiple shapes at once.

By Nick Huggett & Carlo Rovelli

There is a glaring gap in our knowledge of the physical world: none of our well-­established theories describe gravity’s quantum nature. Yet physicists expect that this quantum nature is essential for explaining extreme situations such as the very early universe and the deep interior of black holes. The need to understand it is called the problem of “quantum gravity.”

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“Both galaxies in the Question Mark Pair show active star formation in several compact regions, likely a result of gas from the two galaxies colliding,” said Dr. Vicente Estrada-Carpenter.

How did stars form 7 billion years ago, or approximately halfway between the Big Bang and now? This is what a recent study published in the Monthly Notices of the Royal Astronomical Society hopes to address as an international team of researchers used NASA’s James Webb Space Telescope (JWST) to observe two distant galaxies using the gravitational lensing method, which is a “magnifying glass” that forms around large celestial objects that warp the fabric of space-time. This study holds the potential to help astronomers better understand the conditions in the early universe and the techniques used to study those conditions.

While the gravitational lensing method enables observations of distant objects, those objects also tend to appear distorted due to the space-time warping. In this case, the distant galaxies being observed appear together as a question mark in the JWST images, though astronomers were still able to learn quite a bit about this galaxy. These findings included new insights into star formation, with several stars in the red galaxy exhibiting various stages of formation, including bursty stars, quenching stars, and stars in equilibrium.

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