Menu

Blog

Page 8

Feb 2, 2023

Scientists report on a quasiparticle that can transfer heat under electrical control

Posted by in categories: engineering, particle physics

Scientists have found the secret behind a property of solid materials known as ferroelectrics, showing that quasiparticles moving in wave-like patterns among vibrating atoms carry enough heat to turn the material into a thermal switch when an electrical field is applied externally.

A key finding of the study is that this control of thermal conductivity is attributable to the structure of the material rather than any random collisions among atoms. Specifically, the researchers describe quasiparticles called ferrons whose polarization changes as they “wiggle” in between vibrating atoms—and it’s that ordered wiggling and polarization, receptive to the externally applied , that dictates the material’s ability to transfer the heat at a different rate.

“We figured out that this change in position of these atoms, and the change of the nature of the vibrations, must carry heat, and therefore the external field which changes this vibration must affect the thermal conductivity,” said senior author Joseph Heremans, professor of mechanical and aerospace engineering, and engineering, and physics at The Ohio State University.

Feb 2, 2023

Numerical simulations of planetesimal formation reproduce key properties of asteroids, comets

Posted by in categories: physics, space

With simulations that go into finer details than ever before, Brooke Polak of the University of Heidelberg and Hubert Klahr at the Max Planck Institute for Astronomy (MPIA) have modeled a key phase in the formation of planets in our solar system: the way that centimeter-size pebbles aggregate into so-called planetesimals tens to hundreds kilometers in size. The simulation reproduces the initial size distribution of planetesimals, which can be checked against observations of present-day asteroids. It also predicts the prevalence of close binary planetesimals in our solar system.

In a new study published on arXiv and accepted for publication in The Astrophysical Journal, astrophysicists Brooke Polak from the University of Heidelberg and Hubert Klahr from the Max Planck Institute for Astronomy used simulations to derive key properties of so-called planetesimals—the intermediate-size bodies from which planets formed in our solar system roughly 4.5 billion years ago.

Using an innovative method for simulating planetesimal formation, the two researchers were able to predict the initial size distribution of planetesimals in our solar system: how many are likely to have formed in the different “size brackets” between roughly 10 km and 200 km.

Feb 2, 2023

The bubbling universe: A previously unknown phase transition in the early universe

Posted by in categories: cosmology, particle physics

Think of bringing a pot of water to the boil: As the temperature reaches the boiling point, bubbles form in the water, burst and evaporate as the water boils. This continues until there is no more water changing phase from liquid to steam.

This is roughly the idea of what happened in the very early universe, right after the Big Bang, 13.7 billion years ago.

The idea comes from particle physicists Martin S. Sloth from the Center for Cosmology and Particle Physics Phenomenology at University of Southern Denmark and Florian Niedermann from the Nordic Institute for Theoretical Physics (NORDITA) in Stockholm. Niedermann is a previous postdoc in Sloth’s research group. In this new scientific article, they present an even stronger basis for their idea.

Feb 2, 2023

Evidence found of tidal impact on the plasmasphere

Posted by in categories: particle physics, space

An international team of space scientists reports that the moon exerts a tidal impact on the plasmasphere. For their paper published in the journal Nature Physics, the group used data from multiple spacecraft over a nearly 40-year period to measure tidal perturbations in the plasmapause. Balázs Heilig, with the Institute of Earth Physics and Space Science, in Hungary, has published a News & Views piece in the same journal issue, explaining the nature of the plasmasphere and outlining the work in this new effort.

Early scientists found a connection between the tides and the movement of the thousands of years ago. More recent evidence suggests the moon’s pull acts on the ionosphere as well. In this new study, the researchers wondered if the moon might also have an impact on the plasmasphere.

The plasmasphere is a toroidal mass of plasma that surrounds the Earth. It lies beyond the ionosphere and is made up mostly of electrons and protons. Its particles are charged by the ionosphere, and its outer boundary is known as the plasmapause.

Feb 2, 2023

Here’s how NASA could have tried to rescue the crew of Space Shuttle Columbia if they had known the spacecraft was going to disintegrate on re-entry

Posted by in category: space

On Jan. 16, 2003 space shuttle Columbia left Earth for its 28th and last flight. Even though at the time building the International Space Station was the main goal of the shuttle program, STS-107 (Columbia’s final mission) emphasized pure research, according to Space.com.

The seven-member crew — Rick Husband, commander; Michael Anderson, payload commander; David Brown, mission specialist; Kalpana Chawla, mission specialist; Laurel Clark, mission specialist; William McCool, pilot; and Ilan Ramon, payload specialist from the Israeli Space Agency — had spent 24 hours a day doing science experiments in two shifts.

The seven astronauts on board Columbia were killed on Feb. 1, 2003 when the space shuttle broke up while it was returning to Earth.

Continue reading “Here’s how NASA could have tried to rescue the crew of Space Shuttle Columbia if they had known the spacecraft was going to disintegrate on re-entry” »

Feb 2, 2023

The space between Earth and the moon is about to get a little more crowded

Posted by in category: space travel

With multiple nations and private companies now setting their sights on missions to the moon, experts say cislunar space — the area between Earth and the moon — could become strategically important, potentially opening up competition over resources and positioning, and even sparking geopolitical conflicts.

Feb 2, 2023

Human 2.0 what it means to be human past present and future

Posted by in category: futurism

Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!

Feb 2, 2023

Could a hidden variable explain the weirdness of quantum physics?

Posted by in category: quantum physics

Weirdness of quantum entanglement is explained by hidden variables? If so, we have never found them.

Feb 2, 2023

Seqenenre Tao, the pharaoh who died in battle

Posted by in category: energy

Seqenenre Tao was the pharaoh who ruled southern Egypt in the late 17th dynasty, roughly between 1,558 and 1,553 BC.

That was a troubled time. The Hyksos (whose name in ancient Egyptian was Heqau-khasut, “the rulers of foreign lands”) occupied the northern part of Egypt and took Avaris (present-day Tell el Dabaa) as their capital during a time called the “second intermediate period” (1650−1550 BC).

Although the pharaohs maintained power over the south (with capital in Thebes), the entire territory was forced to pay tribute to the invaders.

Feb 2, 2023

Is Brain Learning Weaker Than Artificial Intelligence?

Posted by in category: robotics/AI

Summary: Artificial neural networks based on human brain dynamics can outperform current deep learning models in learning capabilities.

Source: Bar-Ilan University.

Traditionally, artificial intelligence stems from human brain dynamics. However, brain learning is restricted in a number of significant aspects compared to deep learning (DL).

Page 8 of 8,551First56789101112Last