Archive for the ‘physics’ category: Page 6

Aug 30, 2022

Spectroscopy That Doesn’t Scratch the Surface

Posted by in categories: energy, physics

Researchers have demonstrated a way of measuring the electronic states of a material’s surface while avoiding signal contaminations from deeper layers.

The electronic states of a material’s surface might only be 2D, but they offer a depth of interesting physics. Such states, which are distinct from those of the material’s bulk, dominate many phenomena, such as electrical conduction, magnetism, and catalysis, and they are responsible for nontrivial surface effects found in topological materials and systems with strong spin-orbit interaction. Surface electronic states also control the properties of so-called 2D materials, such as graphene. To understand surface phenomena and harness them in practical devices, researchers chiefly rely on photoemission spectroscopy, which measures the energy and momentum of electrons emitted when photons hit the material. The high resolution with which electron energy and momentum can be characterized allows physicists to measure both the band structure and the density of states (DOS) in the few surface layers where escaping photoelectrons originate.

Aug 30, 2022

Physicists uncover new dynamical framework for turbulence

Posted by in categories: climatology, engineering, information science, physics

Turbulence plays a key role in our daily lives, making for bumpy plane rides, affecting weather and climate, limiting the fuel efficiency of the cars we drive, and impacting clean energy technologies. Yet, scientists and engineers have puzzled at ways to predict and alter turbulent fluid flows, and it has long remained one of the most challenging problems in science and engineering.

Now, physicists from the Georgia Institute of Technology have demonstrated—numerically and experimentally—that turbulence can be understood and quantified with the help of a relatively small set of special solutions to the governing equations of fluid dynamics that can be precomputed for a particular geometry, once and for all.

“For nearly a century, turbulence has been described statistically as a random process,” said Roman Grigoriev. “Our results provide the first experimental illustration that, on suitably short time scales, the dynamics of turbulence is deterministic—and connects it to the underlying deterministic governing equations.”

Aug 30, 2022

X-shaped radio galaxies might form more simply than expected

Posted by in categories: cosmology, physics

When astronomers use radio telescopes to gaze into the night sky, they typically see elliptical-shaped galaxies, with twin jets blasting from either side of their central supermassive black hole. But every once in a while—less than 10% of the time—astronomers might spot something special and rare: An X-shaped radio galaxy, with four jets extending far into space.

Although these mysterious X-shaped radio galaxies have confounded astrophysicists for two decades, a new Northwestern University study sheds new insight into how they form—and its surprisingly simple. The study also found that X-shaped radio galaxies might be more common than previously thought.

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Aug 29, 2022

NTT unveils what it calls the ‘first edge and private 5G’ service

Posted by in categories: internet, physics

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In today’s enterprise, even just a split second in latency can impact performance and access to data — and, thus, the ability to manage and immediately act on it.

But the physics and costs of multicloud and hybrid cloud environments make near-instantaneous response times all but impossible.

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Aug 28, 2022

How the Physics of Nothing Underlies Everything

Posted by in categories: cosmology, physics

Then a mere scientist pulled it off. Otto von Guericke invented a pump to suck the air from within a hollow copper sphere, establishing perhaps the first high-quality vacuum on Earth. In a theatrical demonstration in 1,654, he showed that not even two teams of horses straining to rip apart the watermelon-size ball could overcome the suction of nothing.

Since then, the vacuum has become a bedrock concept in physics, the foundation of any theory of something. Von Guericke’s vacuum was an absence of air. The electromagnetic vacuum is the absence of a medium that can slow down light. And a gravitational vacuum lacks any matter or energy capable of bending space. In each case the specific variety of nothing depends on what sort of something physicists intend to describe. “Sometimes, it’s the way we define a theory,” said Patrick Draper, a theoretical physicist at the University of Illinois.

As modern physicists have grappled with more sophisticated candidates for the ultimate theory of nature, they have encountered a growing multitude of types of nothing. Each has its own behavior, as if it’s a different phase of a substance. Increasingly, it seems that the key to understanding the origin and fate of the universe may be a careful accounting of these proliferating varieties of absence.

Aug 28, 2022

Did the Big Bang happen?

Posted by in categories: cosmology, mathematics, open access, physics

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Physicists have many theories for the beginning of our universe: A big bang, a big bounce, a black hole, a network, a collision of membranes, a gas of strings, and the list goes on. What does this mean? It means we don’t know how the universe began. And the reason isn’t just that we’re lacking data, the reason is that science is reaching its limits when we try to understand the initial condition of the entire universe.

Continue reading “Did the Big Bang happen?” »

Aug 28, 2022

Astronaut Spies “Intriguing Sight” Of Bright Dot On Earth From The ISS

Posted by in categories: computing, physics, space

Orbiting around 420 kilometers (261 miles) above our heads, the astronauts of the Internation Space Station (ISS) get a view of Earth like no other. Sometimes, it’s spectacular auroras, other times it’s something more… curious.

European Space Agency (ESA) astronaut Samantha Cristoforetti – no stranger to having a bit of fun in space – took to Twitter yesterday to share what she called an “intriguing sight”, a bright dot apparently shining in the Negev desert in southern Israel. Related StoriesAfter 175 Years, Two False Conjectures, And The Birth Of Computing, This Theorem Finally Has A ProofExperiment To Find Elusive “Chameleon” Fifth Force Suggests It Doesn’t Actually ExistPerseverance Samples Hold Key To Understanding Water-Rich Martian Past.

Aug 26, 2022

And you thought physicists can’t tell a joke!

Posted by in categories: humor, physics

Aug 25, 2022

Maybe the Universe Thinks. Hear Me Out

Posted by in categories: cosmology, neuroscience, physics

Finally, there’s the issue that black holes can destroy information. Once you have crossed the event horizon, it seems you’d need to move faster than light to get back out. But a non-local connection across the horizon would also get information out. Some physicists have even suggested that dark matter, a hypothetical type of matter that supposedly makes up 85% of matter in the universe, is really a misattribution. There may be only normal matter, it’s just that its gravitational attraction is multiplied and spread out because places are non-locally connected to each other.

A non-locally connected universe, hence, would make sense for many reasons. If these speculations are correct, the universe might be full with tiny portals that connect seemingly distant places. The physicists Fotini Markopoulou and Lee Smolin estimated that our universe could contain as much as 10,360 of such non-local connections. And since the connections are non-local anyway, it doesn’t matter that they expand with the universe. The human brain, for comparison, has a measly 1015connections.

Let me be clear that there is absolutely zero evidence that non-local connections exist, or that, if they existed, they’d indeed allow the universe to think. But we cannot rule this possibility out either. Crazy as it sounds, the idea that the universe is intelligent is compatible with all we know so far.

Aug 25, 2022

NASA Scientists Help Probe Dark Energy

Posted by in categories: cosmology, physics

Could one of the biggest puzzles in astrophysics be solved by reworking Albert Einstein’s theory of gravity? A new study co-authored by NASA scientists says not yet.

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