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Category: cosmology – Page 55

Cosmic rays’ vast energy traced to magnetic turbulence

Ultra-high energy cosmic rays, which emerge in extreme astrophysical environments—like the roiling environments near black holes and neutron stars—have far more energy than the energetic particles that emerge from our sun. In fact, the particles that make up these streams of energy have around 10 million times the energy of particles accelerated in the most extreme particle environment on earth, the human-made Large Hadron Collider.

Where does all that energy come from? For many years, scientists believed it came from shocks that occur in extreme astrophysical environments—when, for example, a star explodes before forming a black hole, causing a huge explosion that kicks up particles.

That theory was plausible, but, according to new research published in The Astrophysical Journal Letters, the observations are better explained by a different mechanism. The source of the cosmic rays’ energy, the researchers found, is more likely magnetic turbulence. The paper’s authors found that magnetic fields in these environments tangle and turn, rapidly accelerating particles and sharply increasing their energy up to an abrupt cutoff.

Neutrinos, Dark Energy, and Einstein: DESI Maps the Universe’s Secrets

New analysis supports Einstein’s relativity and narrows neutrino mass ranges, hinting at evolving dark energy.

Gravity, the fundamental force sculpting the universe, has shaped tiny variations in matter from the early cosmos into the vast networks of galaxies we see today. Using data from the Dark Energy Spectroscopic Instrument (DESI), scientists have traced the evolution of these cosmic structures over the past 11 billion years. This research represents the most precise large-scale test of gravity ever conducted, offering unprecedented insights into the universe’s formation and behavior.

Introduction to DESI and its global impact.

Advanced Simulations Clarify Neutron Star Dynamics and Supernova Physics

Researchers have developed a new computational method to explore the neutron matter inside neutron stars at densities higher than previously studied.

This method provides insights into the behavior of neutrinos during supernova explosions, enhancing the accuracy of simulations and potentially improving our understanding of such cosmic events.

Advances in Neutron Matter Simulation.

The first observed black hole is 50% larger than previous thought, and spins faster than any others

Distance, Mass, and Advanced Observations

To refine the measurements of Cygnus X-1, astronomers used parallax—a technique that calculates stellar distances based on their apparent motion against the backdrop of distant stars as Earth orbits the Sun. Using the Very Long Baseline Array (VLBA), a network of 10 radio telescopes across the United States, researchers tracked the system’s full orbit over six days. They determined that the black hole lies about 7,200 light-years from Earth, significantly farther than the previous estimate of 6,000 light-years.

This updated distance means its blue supergiant companion star is also more massive and brighter than expected, with a mass 40 times that of the Sun. Combined with the black hole’s orbital period, these findings provided the recalculated mass of Cygnus X-1’s black hole.

Google’s new quantum chip cuts key error rate

Currently, dark matter detection requires specialized laboratories with costly equipment. ODIN has the potential to overcome this limitation.

“ODIN’s sensitivity is primarily dependent on phonon density rather than target volume, in contrast to existing systems. This feature may enable compact, low-cost detectors, with the ability to perform lock-in dark matter detection by periodically depopulating the phonon mode,” the study authors explain.

Moreover, the proposed device design features only one optomechanical cavity. Instruments with multiple cavities could result in more exciting results.

The Most Powerful Cosmic Rays Detected Come from Several Points Near Our Solar System

The universe is a stage filled with extreme phenomena, where temperatures and energies reach unimaginable levels. In this context, there are objects such as supernova remnants, pulsars, and active galactic nuclei that generate charged particles and gamma rays with energies far exceeding those involved in nuclear processes like fusion within stars. These particles, as direct witnesses of extreme cosmic processes, offer key insights into the workings of the universe.

Gamma rays, for instance, have the ability to traverse space without being altered, providing direct information about their sources of origin. However, charged particles, known as cosmic rays, face a more complex journey. When interacting with the omnipresent magnetic fields of the cosmos, these particles are deflected and lose part of their energy, especially high-energy electrons and positrons, referred to as cosmic-ray electrons (CRe). With energies surpassing one teraelectronvolt (TeV)—a thousand times more than visible light— these particles gradually fade away, complicating the identification of their point of origin.

Detecting high-energy particles such as CRe is a monumental task. Space instruments, with their limited detection areas, fail to capture sufficient particles at these extreme energies. On the other hand, ground-based observatories face an additional challenge: distinguishing particle cascades triggered by cosmic-ray electrons from the far more frequent ones generated by protons and heavier cosmic-ray nuclei.

Webb telescope’s largest study of universe expansion confirms challenge to cosmic theory

New observations from the James Webb Space Telescope suggest that a new feature in the universe—not a flaw in telescope measurements—may be behind the decade-long mystery of why the universe is expanding faster today than it did in its infancy billions of years ago.

The new data confirms Hubble Space Telescope measurements of distances between and galaxies, offering a crucial cross-check to address the mismatch in measurements of the universe’s mysterious expansion. Known as the Hubble tension, the discrepancy remains unexplained even by the best cosmology models.

“The discrepancy between the observed expansion rate of the universe and the predictions of the standard model suggests that our understanding of the universe may be incomplete. With two NASA flagship telescopes now confirming each other’s findings, we must take this [Hubble tension] problem very seriously—it’s a challenge but also an incredible opportunity to learn more about our universe,” said Nobel laureate and lead author Adam Riess, a Bloomberg Distinguished Professor and Thomas J. Barber Professor of Physics and Astronomy at Johns Hopkins University.