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Category: cosmology – Page 152

Riding the Cosmic Wave: How Plasma Instability Is Changing Our View of the Universe

Scientists from the Leibniz Institute for Astrophysics Potsdam (AIP) have discovered a new plasma instability that promises to revolutionize our understanding of the origin of cosmic rays and their dynamic impact on galaxies.

At the beginning of the last century, Victor Hess discovered a new phenomenon called cosmic rays that later on earned him the Nobel prize. He conducted high-altitude balloon flights to find that the Earth’s atmosphere is not ionized by the radioactivity of the ground. Instead, he confirmed that the origin of ionization was extra-terrestrial. Subsequently, it was determined that cosmic “rays” consist of charged particles from outer space flying close to the speed of light rather than radiation. However, the name “cosmic rays” outlasted these findings.

Recent advances in cosmic ray research.

Revolutionizing the Cosmos: Deep Learning Supercharges Galactic Calculations

Supernovae, which are exploding stars, play a pivotal role in galaxy formation and evolution. However, simulating these phenomena accurately and efficiently has been a significant challenge. For the first time, a team including researchers from the University of Tokyo has utilized deep learning to enhance supernova simulations. This advancement accelerates simulations, crucial for understanding galaxy formation and evolution, as well as the evolution of chemistry that led to life.

When you hear about deep learning, you might think of the latest app that sprung up this week to do something clever with images or generate humanlike text. Deep learning might be responsible for some behind-the-scenes aspects of such things, but it’s also used extensively in different fields of research. Recently, a team at a tech event called a hackathon applied deep learning to weather forecasting. It proved quite effective, and this got doctoral student Keiya Hirashima from the University of Tokyo’s Department of Astronomy thinking.

Webb’s Wonders: A New Holiday Image of Supernova Remnant Cassiopeia A

Just in time for the holidays, NASA’s James Webb Space Telescope (JWST) recently used its Near-Infrared (NIRCam) instrument to capture stunning images of the massive supernova remnant, Cassiopeia A (Cas A), comes after JWST used its Mid-Infrared Instrument (MIRI) to capture its own images of Cas A earlier this year. Along with being comprised of different colors, each image provides different details of Cas A, with some features being visible in one image that aren’t visible in the other image. In either case, this most recent NIRCam image continues to offer stunning insights into one of the most well-known supernova remnants that spans 10 light-years in diameter and located approximately 11,000 light-years from Earth.

Recent image of the supernova remnant, Cassiopeia A (Cas A), taken by NASA’s James Webb Space Telescope, revealing details like never before. (Credit: NASA, ESA, CSA, STScI, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent))

“With NIRCam’s resolution, we can now see how the dying star absolutely shattered when it exploded, leaving filaments akin to tiny shards of glass behind,” said Dr. Danny Milisavljevic, who is an Associate Professor of Physics and Astronomy ay Purdue University and is the research team lead. “It’s really unbelievable after all these years studying Cas A to now resolve those details, which are providing us with transformational insight into how this star exploded.”

Webb stuns with new high-definition look at exploded star

Objects in space reveal different aspects of their composition and behavior at different wavelengths of light. Supernova remnant Cassiopeia A (Cas A) is one of the most well-studied objects in the Milky Way across the wavelength spectrum. However, there are still secrets hidden within the star’s tattered remains.

The latest are being unlocked by one of the newest tools in the researchers’ toolbox, the James Webb Space Telescope—and Webb’s recent look in the near-infrared has blown researchers away.

Like a shiny, round ornament ready to be placed in the perfect spot on a holiday tree, supernova remnant Cassiopeia A (Cas A) gleams in a new image from NASA’s James Webb Space Telescope.

Inconsistency Turns Up Again for Cosmological Observations

A new analysis of the distribution of matter in the Universe continues to find a discrepancy in the clumpiness of dark matter in the late and early Universe, suggesting a fundamental error in the standard cosmological model.

Cosmologists study the Universe by making a vast range of observations using a variety of modern techniques. Each observation can reveal different details about the Universe’s composition over a certain period of its history. An astronomical survey—a map of a region of the sky—is a powerful way to scan a large swath of the Universe and the objects it contains. For example, a weak-lensing survey does that by obtaining sharp images of galaxies, which can then be used to map the distribution of the Universe’s matter throughout history. The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is one such weak-lensing survey, and it has the highest resolution and the deepest depth of all current weak-lensing surveys. Over the past six years, the HSC-SSP survey team has spent 330 nights scanning 3% of the entire spherical sky, capturing the light emitted by galaxies up to 10 billion years ago.

Crisis in Cosmology: New Study Exacerbates Expansion Rate Disagreement

The current measurements of the expansion rate of the universe are in disagreement, leading to a crisis in cosmology and the need for renewed research efforts into new physics and a new model of the universe.

Questions to inspire discussion.

What is the crisis in cosmology?
—The crisis in cosmology refers to the disagreement between measurements of the expansion rate of the universe, leading to the need for renewed research efforts into new physics and a new model of the universe.

Beyond Einstein: A Solution to One of the Great Mysteries of Cosmology

Study by the Universities of Bonn and St. Andrews proposes a new possible explanation for the Hubble tension.

The universe is expanding. How fast it does so is described by the so-called Hubble-Lemaitre constant. But there is a dispute about how big this constant actually is: Different measurement methods provide contradictory values. This so-called “Hubble tension” poses a puzzle for cosmologists. Researchers from the Universities of Bonn and St. Andrews are now proposing a new solution: Using an alternative theory of gravity, the discrepancy in the measured values can be easily explained — the Hubble tension disappears. The study has now been published in the Monthly Notices of the Royal Astronomical Society (MNRAS).

Understanding the Universe’s Expansion.