Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: particle physics – Page 266

The ability to transmit and manipulate, with minimal loss, the smallest unit of light—the photon—plays a pivotal role in optical communications as well as designs for quantum computers that would use light rather than electric charges to store and carry information.

Now, researchers at the National Institute of Standards and Technology (NIST) and their colleagues have connected, on a single microchip, quantum dots—artificial atoms that generate individual photons rapidly and on-demand when illuminated by a laser—with miniature circuits that can guide the light without significant loss of intensity.

To create the ultra-low-loss circuits, the researchers fabricated silicon-nitride waveguides—the channels through which the photons traveled—and buried them in silicon dioxide. The channels were wide but shallow, a geometry that reduced the likelihood that photons would scatter out of the waveguides. Encapsulating the waveguides in silicon dioxide also helped to reduce scattering.

Read more | >

Pity the poor astronomer. Biologists can hold examples of life in their hands. Geologists can fill specimen cabinets with rocks. Even physicists get to probe subatomic particles in laboratories built here on Earth. But across its millennia-long history, astronomy has always been a science of separation. No astronomer has stood on the shores of an alien exoplanet orbiting a distant star or viewed an interstellar nebula up close. Other than a few captured light waves crossing the great void, astronomers have never had intimate access to the environments that spur their passion.

Until recently, that is. At the turn of the 21st century, astrophysicists opened a new and unexpected era for themselves: large-scale laboratory experimentation. High-powered machines, in particular some very large lasers, have provided ways to re-create the cosmos, allowing scientists like myself to explore some of the universe’s most dramatic environments in contained, controlled settings. Researchers have learned to explode mini supernovas in their labs, reproduce environments around newborn stars, and even probe the hearts of massive and potentially habitable exoplanets.

How we got here is one of the great stories of science and synergy. The emergence of this new large-scale lab-based astrophysics was an unanticipated side effect of a much broader, more fraught, and now quite in-the-news scientific journey: the quest for nuclear fusion. As humanity has worked to capture the energy of the stars, we’ve also found a way to bring the stars down to Earth.

Read more | >

Water on the Moon has been a hot topic in the research world lately. Since its first unambiguous discovery back in 2008. Since then, findings of it have ramped up, with relatively high concentration levels being discovered, especially near the polar regions, particularly in areas constantly shrouded in shadow. Chang’e 5, China’s recent sample return mission, didn’t land in one of those permanently shadowed areas. Still, it did return soil samples that were at a much higher latitude than any that had been previously collected. Now, a new study shows that those soil samples contain water and that the Sun’s solar wind directly impacted that water.

The amount of water on the lunar surface varies widely both based on the time of the lunar day and the latitude it is located at. There is so much variability that the water content of the lunar soil can be 200 ppm higher or lower at different times of the day. With that much variability, it seems clear that the Sun plays a significant role in the hydrological cycle there is on the Moon.

Part of that role is controlling the type of hydrogen embedded into the lunar soil. Since the Moon has almost no atmosphere to speak of, the charged hydrogen particles that make up the solar wind can directly interact with the top regolith layer on the lunar surface. When they do so, they leave behind a distinct sign that they do – a large amount of hydrogen atoms with very little deuterium.

Read more | >

Year 2021 face_with_colon_three

“This [study] shows us the evolution of the QGP and eventually [could] suggest how the early universe evolved in the first microsecond after the Big Bang,” said co-author You Zhou, an associate professor at the Niels Bohr Institute, University of Copenhagen in Denmark in an official statement.

“First the plasma that consisted of quarks and gluons was separated by the hot expansion of the universe. Then the pieces of quark reformed into so-called hadrons. A hadron with three quarks makes a proton, which is part of atomic cores. These cores are the building blocks that constitutes earth, ourselves and the universe that surrounds us.”

Following the chaotic Big Bang event, the universe was believed to be a violent soup of energy prior to it quickly expanding in a process known as inflation, where the infant universe cools to a point when matter is eventually formed.

Read more | >

In a new study, scientists say they can explain dark matter by positing a particle that links to a fifth dimension.

(Updated version of the previous article.)

While the “warped extra dimension” (WED) is a trademark of a popular physics model first introduced in 1999, this research, published in The European Physical Journal C, is the first to cohesively use the theory to explain the long-lasting dark matter problem within particle physics.

Read more | >

Although dark matter is a central part of the standard cosmological model, it’s not without its issues. There continue to be nagging mysteries about the stuff, not the least of which is the fact that scientists have found no direct particle evidence of it.

Despite numerous searches, we have yet to detect . So some astronomers favor an alternative, such as modified Newtonian dynamics (MoND) or modified . And a new study of galactic rotation seems to support them.

The idea of MoND was inspired by galactic rotation. Most of the visible matter in a galaxy is clustered in the middle, so you’d expect that stars closer to the center would have faster orbital speeds than stars farther away, similar to the planets of our solar system. What we observe is that stars in a galaxy all rotate at about the same speed. The rotation curve is essentially flat rather than dropping off. The dark matter solution is that galaxies are surrounded by a halo of invisible matter, but in 1983 Mordehai Milgrom argued that our gravitational model must be wrong.

Read more | >

A team of researchers from Università di Firenze, the University of South Florida, California Institute of Technology and Princeton University has found an incidence of a quasicrystal formed during an accidental electrical discharge.

In their paper published in Proceedings of the National Academy of Sciences, the group describes their study of a quasicrystal found in a in Nebraska.

Quasicrystals, as their name suggests, are crystal-like substances. They possess characteristics not found in ordinary crystals, such as a non-repeating arrangement of atoms. To date, quasicrystals have been found embedded in meteorites and in the debris from nuclear blasts. In this new effort, the researchers found one embedded in a sand dune in Sand Hills, Nebraska.

Read more | >

An aerial fireworks burst is produced by launching a fireworks shell high into the air, where an explosion occurs. This explosion propels brightly burning particles (known as “stars”) in many directions. Each streak of light in the firework is a burning “star” flying through the air.

Coal and saltpeter (potassium-nitrate) are used to create gunpowder, the fuel that allows the stars in the firework to burn. Nitratine, a highly reactive mineral, is the natural form of sodium-nitrate and serves as an oxidizer for fireworks, supporting the fuel’s combustion.

The vibrant colors in a firework don’t come directly from the burning fuel, but metallic minerals that are deliberately added in very small amounts to the mix. As the fuel burns, the metal atoms in the crystal structure absorb energy, emitting a specific wavelength of light that we perceive as a distinct color.

Read more | >