Archive for the ‘physics’ category

Nov 29, 2023

Dark matter could help solve the final parsec problem of black holes

Posted by in categories: computing, cosmology, information science, physics

When galaxies collide, their supermassive black holes enter into a gravitational dance, gradually orbiting each other ever closer until eventually merging. We know they merge because we see the gravitational beasts that result, and we have detected the gravitational waves they emit as they inspiral. But the details of their final consummation remain a mystery. Now a new paper published on the pre-print server arXiv suggests part of that mystery can be solved with a bit of dark matter.

Just as the famous three-body problem has no general analytical solution for Newtonian gravity, the two-body problem has no general solution in . So, we have to resort to to model how black holes orbit each other and eventually merge.

For that are relatively widely separated, our simulations work really well, but when black holes are close to each other things get complicated. Einstein’s equations are very nonlinear, and modeling the dynamics of strongly interacting black holes is difficult.

Nov 29, 2023

A gamma-ray pulsar milestone inspires innovative astrophysics and applications

Posted by in categories: energy, physics, space

The U.S. Naval Research Laboratory (NRL), in conjunction with the international Fermi Large Area Telescope Collaboration, announce the discovery of nearly 300 gamma ray pulsars in the publication of their Third Catalog of Gamma Ray Pulsars. This milestone comes 15 years after the launch of Fermi in 2008 when there were fewer than ten known gamma-ray pulsars.

“Work on this important catalog has been going on in our group for years,” said Paul Ray, Ph.D., head of the High Energy Astrophysics and Applications Section at NRL. “Our scientists and postdocs have been able to both discover and analyze the timing behavior and spectra of many of these newfound pulsars as part of our quest to further our understanding of these exotic stars that we are able to use as cosmic clocks.”

Pulsars are formed when have burned through their fuel supply and become unable to resist the inward pull of their own gravity. This results in the star collapsing into a dense, spinning, magnetized neutron star. Their spinning magnetic fields send out beams of gamma rays, the most energetic form of light. As these beams sweep across the Earth, the highly sensitive Fermi gamma-ray telescope can observe their periodic energy pulses. With more than 15 years of data, Fermi has transformed the field of research.

Nov 29, 2023

From The Big Bang To The Present: The Evolution Of The Universe

Posted by in categories: cosmology, evolution, physics

Author: Sharika Dhakappa The Big Bang is the most widely accepted theory of how the universe originated. Most physicists believe that the tremendously large universe we observe today began as a tiny, dense point. If the evolution of the universe till today were to be depicted as a movie, the Big Bang would be the beginning of it. We do not yet know what came before the Big Bang or whether that is even a meaningful question to ask. The cosmic movie would run for 13.8 billion years which is the current age of the universe as estimated by the WMAP satellite.

Nov 26, 2023

Earth’s Center Is 2 Years Younger Than Its Surface Because Of Time Dilation

Posted by in categories: physics, space

Here’s an unusual fact that takes a bit of explaining. The center of the Earth is around two and a half years younger than the surface.

About 4.6 billion years ago, a hot cloud of dust orbiting the Sun coalesced and cooled. As it did so, the heavier elements formed the center of the Earth, while lighter elements formed the mantle, and the thin layer of crust formed on the surface. This all took place at the same time, with the minor caveat that Earth has accumulated more matter in the intervening years, including potentially from planet Theia, which may have formed the Moon and left mysterious structures deep within the Earth. And yet now the center is younger than the outer bits. How?

A team of physicists calculated this strange fact in 2016. The team was aware that in the 1960s theoretical physicist Richard Feynman gave a lecture in which he stated, according to the possibly erroneous transcription, that the center of the Earth is “one or two days” younger than the surface because of the time-dilating effects of gravity. The team write that they had seen this claim repeated without being checked, likely due to “proof by ethos”, where a scientist’s status is so high that their results and calculations aren’t questioned.

Nov 25, 2023

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES): “Astronomers find the key for detecting the largest structures in the early universe”

Posted by in categories: physics, space

From IAC-The Institute of Astrophysics of the Canary Islands [Instituto de Astrofísica de Canarias] (ES)

11.21.23 Helmut Dannerbauer [email protected].

Artist’s impression of a protocluster of galaxies in the early Universe showing galaxies forming new stars and interacting with each other. Credit: M. Kornmesser/ESO.

Nov 25, 2023

This AI Paper Introduces Φ-SO: A Physical Symbolic Optimization Framework that Uses Deep Reinforcement Learning to Discover Physical Laws from Data

Posted by in categories: information science, physics, robotics/AI

Artificial Intelligence and Deep learning have brought about some great advancements in the field of technology. They are enabling robots to perform activities that were previously thought to be limited to human intelligence. AI is changing the way humans approach problems and bringing revolutionary transformations and solutions to almost every industry. Teaching machines to learn from massive amounts of data and make decisions or predictions based on that learning is the basic idea behind AI. Its application in scientific endeavors has given rise to some amazing tools that are gaining massive popularity in the AI community.

In Artificial Intelligence, Symbolic Regression has been playing an important role in the subtleties of scientific research. It basically focuses on algorithms that allow machines to interpret complicated patterns and correlations found in datasets by automating the search for analytic expressions. Scientists and researchers have been putting in efforts to explore the possible uses of Symbolic Regression.

Diving into the field of Symbolic Regression, a team of researchers has recently introduced Φ-SO, a Physical Symbolic Optimization framework. This method navigates the complexities of physics, where the presence of units is crucial. It automates the process of finding analytic expressions fitting complex datasets.

Nov 24, 2023

Simulating the Cosmos: Is a Miniature Universe Possible?

Posted by in categories: computing, education, physics, space

Wouldn’t it be nice to have a computer answer all of the biggest questions in the universe?

In his first year of graduate school, in 2013, Michael Wagman walked into his advisor’s office and asked, “Can you help me simulate the universe?”

Wagman, a theoretical physicist and associate scientist at the US Department of Energy’s Fermi National Accelerator Laboratory, thought it seemed like a reasonable question to ask. “We have all of these beautiful theoretical descriptions of how we think the world works, so I wanted to try and connect those formal laws of physics to my everyday experience of reality,” he says.

Nov 23, 2023

NASA’s New Power Play: Plutonium-238 for Distant Space Journeys

Posted by in categories: energy, government, physics, space

The DOE’s shipment of 0.5 kilograms of plutonium-238 to Los Alamos National Laboratory marks a milestone in producing fuel for NASA

Established in 1958, the National Aeronautics and Space Administration (NASA) is an independent agency of the United States Federal Government that succeeded the National Advisory Committee for Aeronautics (NACA). It is responsible for the civilian space program, as well as aeronautics and aerospace research. Its vision is “To discover and expand knowledge for the benefit of humanity.” Its core values are “safety, integrity, teamwork, excellence, and inclusion.” NASA conducts research, develops technology and launches missions to explore and study Earth, the solar system, and the universe beyond. It also works to advance the state of knowledge in a wide range of scientific fields, including Earth and space science, planetary science, astrophysics, and heliophysics, and it collaborates with private companies and international partners to achieve its goals.

Nov 23, 2023

Tri-Star Revolution: “Triple Star” Discovery Shakes Up Stellar Evolution Theories

Posted by in categories: cosmology, physics

A groundbreaking study by University of Leeds scientists proposes that Be stars are part of triple star systems, not binary systems as previously thought. This finding, derived from Gaia satellite data, challenges conventional star formation theories and could impact our knowledge of black holes, neutron stars, and gravitational waves.

Gravitational waves are distortions or ripples in the fabric of space and time. They were first detected in 2015 by the Advanced LIGO detectors and are produced by catastrophic events such as colliding black holes, supernovae, or merging neutron stars.

Nov 20, 2023

Sean Carroll on Causality and the Arrow of Time

Posted by in categories: cosmology, physics

Sean Carroll speaking at the 6th International FQXi Conference, “Mind Matters: Intelligence and Agency in the Physical World.”

The Foundational Questions Institute (FQXi) catalyzes, supports, and disseminates research on questions at the foundations of physics and cosmology, particularly new frontiers and innovative ideas integral to a deep understanding of reality but unlikely to be supported by conventional funding sources.

Continue reading “Sean Carroll on Causality and the Arrow of Time” »

Page 1 of 26012345678Last