Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: physics

In a breakthrough for physics and engineering, researchers from the Photonics Initiative at the Advanced Science Research Center at The Graduate Center, CUNY (CUNY ASRC) and from Georgia Tech have presented the first demonstration of topological order based on time modulations. This advancement allows the researchers to propagate sound waves along the boundaries of topological metamaterials without the risk of waves traveling backwards or being thwarted by material defects.

The new findings, which appear in the journal Science Advances, will pave the way for cheaper, lighter devices that use less battery power, and which can function in harsh or hazardous environments. Andrea Alù, founding director of the CUNY ASRC Photonics Initiative and Professor of Physics at The Graduate Center, CUNY, and postdoctoral research associate Xiang Ni were authors on the paper, together with Amir Ardabi and Michael Leamy from Georgia Tech.

The field of topology examines properties of an object that are not affected by continuous deformations. In a topological insulator, electrical currents can flow along the object’s boundaries, and this flow is resistant to being interrupted by the object’s imperfections. Recent progress in the field of metamaterials has extended these features to control the propagation of sound and light following similar principles.

Read more | >

A short gamma ray burst left the most-distant optical afterglow ever detected –incredibly faint and fast signals sometimes lasting mere hours–some 10 billion light years away, 3.8 billion years after the Big Bang. Astronomers suspect that up to one-third of all short gamma ray bursts come from merging neutron stars in globular clusters of old stars blinding whole galaxies with light and destroying millions of worlds. Known as SGRB181123B, it is the second most-distant well-established SGRB ever detected and the most distant event with an optical afterglow.

The appearance of an SGRB at such an early time, report astronomers at the Keck Observatory and Northwestern University could alter theories about their origins, particularly the length of time it takes two neutron stars to merge and produce these powerful explosions, as well as the rate of neutron star mergers in the young universe.

“This was a very exciting object to study,” said Kerry Paterson, a postdoctoral associate at Northwestern University’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and lead author of the study. “Our research now suggests neutron star mergers could occur surprisingly quickly for some systems — with neutron star binaries spiraling together in less than a billion years to create an SGRB.”

Read more | >

“There is conceivably a way to do warp drive.” Elon Musk discusses warping space within the known laws of physics, the expansion of the universe being faster than the speed of light (which allow us to see back in time when looking into space) and dark matter.

Read more | >

A ringing bell vibrates simultaneously at a low-pitched fundamental tone and at many higher-pitched overtones, producing a pleasant musical sound. A recent study, just published in the Journal of the Atmospheric Sciences by scientists at Kyoto University and the University of Hawai’i at Mānoa, shows that the Earth’s entire atmosphere vibrates in an analogous manner, in a striking confirmation of theories developed by physicists over the last two centuries.

In the case of the , the “music” comes not as a sound we could hear, but in the form of large-scale waves of spanning the globe and traveling around the equator, some moving east-to-west and others west-to-east. Each of these waves is a resonant vibration of the global atmosphere, analogous to one of the resonant pitches of a bell. The basic understanding of these atmospheric resonances began with seminal insights at the beginning of the 19th century by one of history’s greatest scientists, the French physicist and mathematician Pierre-Simon Laplace. Research by physicists over the subsequent two centuries refined the theory and led to detailed predictions of the wave frequencies that should be present in the atmosphere. However, the actual detection of such waves in the has lagged behind the theory.

Now in a new study by Takatoshi Sakazaki, an assistant professor at the Kyoto University Graduate School of Science, and Kevin Hamilton, an Emeritus Professor in the Department of Atmospheric Sciences and the International Pacific Research Center at the University of Hawai?i at Mānoa, the authors present a detailed analysis of observed atmospheric pressure over the globe every hour for 38 years. The results clearly revealed the presence of dozens of the predicted wave modes.

Read more | >

If you stack two layers of graphene one on top of the other, and rotate them at an angle of 1.1º (no more and no less) from each other—the so-called ‘magic-angle,’ experiments have proven that the material can behave like an insulator, where no electrical current can flow, and at the same can also behave like a superconductor, where electrical currents can flow without resistance.

This major finding took place in 2018. Last year, in 2019, while ICFO researchers were improving the quality of the device used to replicate such breakthroughs, they stumbled upon something even bigger and totally unexpected. They were able to observe a zoo of previously unobserved superconducting and correlated states, in addition to an entirely new set of magnetic and topological states, opening a completely new realm of richer physics.

So far, there is no theory that has been able to explain superconductivity in magic angle graphene at the microscopic level. However, this finding has triggered many studies, which are trying to understand and unveil the physics behind all these phenomena that occur in this material. In particular, scientists drew analogies to unconventional high temperature superconductors—the cuprates, which hold the record highest superconducting temperatures, only 2 times lower than . Their microscopic mechanism of the superconducting phase is still not understood, 30 years after its discovery. However, similarly to magic angle twisted bi-layer graphene (MATBG), it is believed that an insulating phase is responsible for the superconducting phase in proximity to it. Understanding the relationship between the superconducting and insulating phases is at the center of researcher’s interest, and could lead to a big breakthrough in superconductivity research.

Read more | >

On March 12th 2020 a space telescope called Swift detected a burst of radiation from halfway across the Milky Way. Within a week, the newly discovered X-ray source, named Swift J1818.0–1607, was found to be a magnetar, a rare type of slowly rotating neutron star with one of the most powerful magnetic fields in the universe.

Spinning once every 1.4 seconds, it’s the fastest spinning known, and possibly one of the youngest in the Milky Way. It also emits pulses like those seen from pulsars—another type of rotating neutron star. At the time of this detection, only four other radio-pulse-emitting magnetars were known, making Swift J1818.0–1607 an extremely rare discovery.

In a recently published study led by a team of scientists from the ARC Center of Excellence for Gravitational Wave Discovery (OzGrav), it was found that the pulses from the magnetar become significantly fainter when going from low to high : It has a steep radio spectrum. Its radio emission is not only steeper than the four other radio magnetars, but also steeper than ~90% of all pulsars. Additionally, they found the magnetar had become over 10 times brighter in only two weeks.

Read more | >

Astronomers have found a way to pinpoint our solar system’s center of mass to within a mere 330 feet (100 meters), a recent study reports.

Such precision — equivalent to the width of a human hair on the scale of a football field — could substantially aid the search for powerful gravitational waves that warp our Milky Way galaxy, study team members said.

Read more | >

Supernovae are some of the most energetic events in the universe, and the resulting nebulas are a favorite for stargazers. To better understand the physics behind them, researchers at Georgia Tech have created a “supernova machine” in the lab.

Stars are basically big volatile balls of gas, sustained for millions of years by a delicate balancing act. Intense gravity wants to pull the matter towards the center, but nuclear fusion in the core is pushing outwards at the same time. Eventually though, the core inevitably runs out of nuclear fuel, and gravity wins the battle.

The star then collapses inwards very quickly, and the resulting shock wave sends material flying outwards at extreme speeds. The event is a supernova, the swirling gas and matter is a nebula, and the dense object formed in the center is a neutron star or a black hole.

Read more | >