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Category: physics – Page 123

Emmy Noether: the woman who developed one of the most beautiful theorems in physics

Imagine a juggler tossing balls into the air. The art of juggling is a dance between motion and pause, where the ball’s speed slows as it ascends, and then quickens on the way down. This dance reveals one of the core tenets of physics: conservation laws.

Simply put, these laws tell us that certain features of our world, like energy, don’t just vanish; they transform from one form to another. In our juggling example, the energy of motion (kinetic energy) morphs into the energy of position (potential energy) and back again.

Conservation laws aren’t just limited to juggling, or even Earth for that matter. They’re universal principles, true across various fields of physics. Yet, they aren’t always straightforward.

Chi-Nu experiment ends, bolsters nuclear security and energy reactors

The results of the Chi-Nu physics experiment at Los Alamos National Laboratory have contributed essential, never-before-observed data for enhancing nuclear security applications, understanding criticality safety and designing fast-neutron energy reactors. The Chi-Nu project, a years-long experiment measuring the energy spectrum of neutrons emitted from neutron-induced fission, recently concluded the most detailed and extensive uncertainty analysis of the three major actinide elements—uranium-238, uranium-235 and plutonium-239.

“Nuclear and related nuclear chain reactions were only discovered a little more than 80 years ago, and experimenters are still working to provide the full picture of fission processes for the major actinides,” said Keegan Kelly, a physicist at Los Alamos National Laboratory. “Throughout the course of this project, we have observed clear signatures of fission processes that in many cases were never observed in any previous experiment.”

The Los Alamos team’s final Chi-Nu study, on the isotope uranium-238, was recently published in Physical Review C. The experiment measured uranium-238’s prompt fission spectrum: the energy of the neutron inducing the fission—the neutron that crashes into a nucleus and splits it—and the potentially wide-ranging energy distribution (the spectrum) of the neutrons released as a result. Chi-Nu focuses on “fast-neutron-induced” fission, with incident neutron energies in millions of electron volts, where there have typically been very few measurements.

James Webb just Found a Supernova That Could Break the Laws of Physics

In this episode, we explore how a triple-lens supernova observed by the James Webb Space Telescope could help solve the mystery of the Hubble tension, which is the discrepancy between different measurements of the expansion rate of the Universe. We also learn about the details of the supernova and the galaxy cluster that caused the gravitational lensing effect, and how JWST and other telescopes can use this supernova to test various cosmological models and parameters.

Paper Link:
https://arxiv.org/abs/2309.

Chapters:
00:00 Introduction.
01:10 How JWST Discovered a Rare and Triple-Lens Supernova.
04:13 How H0pe Can Measure the Expansion Rate in a New Way.
09:00 How hOpe can test various cosmological models.
11:26 Outro.
12:24 Enjoy.

Best Telescopes for beginners:
Celestron 70mm Travel Scope.
https://amzn.to/3jBi3yY

Celestron 114LCM Computerized Newtonian Telescope.
https://amzn.to/3VzNUgU

Celestron – StarSense Explorer LT 80AZ

Continue reading “James Webb just Found a Supernova That Could Break the Laws of Physics” | >

Unlocking Battery Mysteries: X-Ray “Computer Vision” Reveals Unprecedented Physical and Chemical Details

It lets researchers extract pixel-by-pixel information from nanoscale.

The nanoscale refers to a length scale that is extremely small, typically on the order of nanometers (nm), which is one billionth of a meter. At this scale, materials and systems exhibit unique properties and behaviors that are different from those observed at larger length scales. The prefix “nano-” is derived from the Greek word “nanos,” which means “dwarf” or “very small.” Nanoscale phenomena are relevant to many fields, including materials science, chemistry, biology, and physics.

Theoretical study shows that Kerr black holes could amplify new physics

Black holes are regions in space characterized by extremely strong gravity, which prevents all matter and electromagnetic waves from escaping it. These fascinating cosmic bodies have been the focus of countless research studies, yet their intricate physical nuances are yet to be fully uncovered.

Researchers at University of California–Santa Barbara, University of Warsaw and University of Cambridge recently carried out a theoretical study focusing on a class of known as extremal Kerr black holes, which are uncharged stationary black holes with a coinciding inner and outer horizon. Their paper, published in Physical Review Letters, shows that these black holes’ unique characteristics could make them ideal “amplifiers” of new, unknown .

“This research has its origin in a previous project started during my visit to UC Santa Barbara,” Maciej Kolanowski, one of the researchers who carried out the study, told Phys.org. “I started discussing very cold (so called, extremal) black holes with Gary Horowitz (UCSB) and Jorge Santos (at Cambridge). Soon we realized that in fact, generic extremal black holes look very different than it was previously believed.”

World’s most powerful X-ray laser fired for the first time

With up to a million X-ray flashes a second, the laser will help study mechanisms in physics, chemistry, and biology.

The US Department of Energy’s (DOE) SLAC National Accelerator Laboratory has fired the first X-rays using the upgraded Linac Coherent Light Source (LCLS) X-ray free-electron laser (XFEL), a press release said. The upgraded version, dubbed LCLS-II, was built for $1.1 billion.

The SLAC National Accelerator Laboratory at Stanford has been building and operating powerful tools for advancing science for over six decades. The original LCLS was the world’s first XFEL, reaching its first light in April 2009.

Scientists figured out how to write in water

Human writing and drawing dates back at least 30,000 years and incorporates traditional techniques such as carving, engraving, and printing/writing with ink, as well as more novel methods such as electron lithography. Now a team of German physicists has figured out a unique method for writing in water and other fluid substrates, according to a recent paper published in the journal Small.

According to the authors, most classical writing methods involve the same basic approach, in which a line is carved out or ink deposited. On a solid substrate, strong intermolecular forces help the written figures hold their shape, but that’s not the case for surfaces submerged in fluids. Prior research has used scanning probe lithography to “write’ on self-assembled monolayers submerged in fluids, or to bring structures at the micron scale using two-photon polymerization. ” There are now even commercial scuba diver slates available for underwater writing on a substrate,” they wrote.

All of these methods still rely on a substrate, however. The German team wanted to devise a means of literally writing into a fluid. Such a method would need to be robust enough to counter the rapid dispersion of drawn lines, and they would need a very tiny pen that didn’t stir up lots of turbulence as it moved through the fluid medium. (The smaller the object moving through a fluid, the fewer vortices, or eddies, it will create.)