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Archive for the ‘physics’ category: Page 159

Mar 2, 2020

The Rules of the Flock

Posted by in category: physics

The locusts have no king, and yet they all go forth in ranks, noted King Solomon some three thousand years ago. That a multitude of simple creatures could display coherent collective behavior without any leader caused his surprise and amazement, and it has continued to do so for much of our thinking over the following millennia. Caesar’s legions conquered Europe, Napoleon’s armies reached Moscow: We always think of a great commander telling the thoughtless multitudes what to do.

Statistical physics pioneered an opposite view. When a piece of iron is cooled down to a certain temperature (the Curie temperature), the majority of the atoms align their spins, thereby making it magnetic. No atomic general gives any commands; each atom communicates only with its neighbors, and yet there is an overall alignment. It shows us that local microscopic interactions as such can lead to dramatic global behavior, and this realization brought about a revolution in the understanding of swarm behavior.

Some hundred years ago, serious biologists still thought that the coordination of birds in a flock was reached by telepathy, and the synchronized light emission by fireflies in the Asiatic jungle was attributed to faulty observation by the observer. The introduction of physics concepts in biology has to a large extent resolved these puzzles. Flocks of birds are much more like the atoms in iron than they are like the armies of Napoleon, and the fireflies act much like a laser. Collective behavior in the world of living beings is after all not so different from that in the inanimate world.

Continue reading “The Rules of the Flock” »

Mar 1, 2020

Unraveling turbulence: New insights into how fluids transform from order to disorder

Posted by in categories: physics, transportation

Turbulence is everywhere—it rattles our planes and makes tiny whirlpools in our bathtubs—but it is one of the least understood phenomena in classical physics.

Turbulence occurs when an ordered fluid flow breaks into small vortices, which interact with each other and break into even smaller vortices, which interact with each other and so-on, becoming the chaotic maelstrom of disorder that makes white water rafting so much fun.

But the mechanics of that descent into chaos have puzzled scientists for centuries.

Mar 1, 2020

Physicists model the supernovae that result from pulsating supergiants like Betelgeuse

Posted by in categories: cosmology, physics

Betelgeuse has been the center of significant media attention lately. The red supergiant is nearing the end of its life, and when a star over 10 times the mass of the Sun dies, it goes out in spectacular fashion. With its brightness recently dipping to the lowest point in the last hundred years, many space enthusiasts are excited that Betelgeuse may soon go supernova, exploding in a dazzling display that could be visible even in daylight.

While the famous star in Orion’s shoulder will likely meet its demise within the next million years—practically couple days in cosmic time—scientists maintain that its dimming is due to the star pulsating. The phenomenon is relatively common among red supergiants, and Betelgeuse has been known for decades to be in this group.

Coincidentally, researchers at UC Santa Barbara have already made predictions about the brightness of the supernova that would result when a pulsating star like Betelgeuse explodes.

Feb 29, 2020

Black Holes Are Nothing But Holograms, New Study Finds

Posted by in categories: cosmology, holograms, physics

Black holes are one of the most mysterious objects astronomer have encountered so far. And a new study proposes that black are nothing but just a holographic projection, with a new calculation of the entropy — or also known as disorder. These calculations suggest that these giant enigmas of the Universe being nothing but an optical illusion. Holograph hypothesis was first proposed by physicist Leonard Susskind back in the 1990s, according to this theory, mathematically speaking, the Universe requires just two dimensions — not three — for the laws of physics and gravity to work as they really should.

Feb 27, 2020

Physicists may have accidentally discovered a new state of matter

Posted by in categories: climatology, computing, mobile phones, physics

Humans have been studying electric charge for thousands of years, and the results have shaped modern civilization. Our daily lives depend on electric lighting, smartphones, cars, and computers, in ways that the first individuals to take note of a static shock or a bolt of lightning could never have imagined.

Now, physicists at Northeastern have discovered a new way to manipulate . And the changes to the future of our technology could be monumental.

“When such phenomena are discovered, imagination is the limit,” says Swastik Kar, an associate professor of physics. “It could change the way we can detect and communicate signals. It could change the way we can sense things and the storage of information, and possibilities that we may not have even thought of yet.”

Feb 25, 2020

This is how ESA telescope Euclid is going to visualize dark matter

Posted by in categories: cosmology, physics

How can you see something that’s invisible? Well, with Euclid! This future ESA telescope will map the structure of the universe and teach us more about invisible dark matter and dark energy. Scientific coordinator of Euclid and Leiden astronomer Henk Hoekstra explains how this works.

Why do we assume that exists, if we have never seen it or even measured it? “We are orbiting the centre of our galaxy at 220 kilometres per second,” says Hoeksta. A bizarre speed, which fortunately we don’t notice. Still, something strange is going on. “Based on the number of stars in our Milky Way, the stars at the edge of the Milky Way should have a much lower speed, but they move as fast as the Sun. Yet these stars are not being slung into the . Something is holding them together.”

Continue reading “This is how ESA telescope Euclid is going to visualize dark matter” »

Feb 25, 2020

Design of the W7-X fusion device enables it to overcome obstacles, scientists find

Posted by in categories: nuclear energy, physics

A key hurdle facing fusion devices called stellarators—twisty facilities that seek to harness on Earth the fusion reactions that power the sun and stars—has been their limited ability to maintain the heat and performance of the plasma that fuels those reactions. Now collaborative research by scientists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and the Max Planck Institute for Plasma Physics in Greifswald, Germany, have found that the Wendelstein 7-X (W7-X) facility in Greifswald, the largest and most advanced stellarator ever built, has demonstrated a key step in overcoming this problem.

Cutting-edge facility

The cutting-edge facility, built and housed at the Max Planck Institute for Plasma Physics with PPPL as the leading U.S. collaborator, is designed to improve the performance and stability of the plasma—the hot, charged state of matter composed of free electrons and atomic nuclei, or ions, that makes up 99 percent of the visible universe. Fusion reactions fuse ions to release massive amounts of energy—the process that scientists are seeking to create and control on Earth to produce safe, clean and virtually limitless power to generate electricity for all humankind.

Feb 24, 2020

Gravitational Waves Have Revealed a Stellar Mystery

Posted by in categories: physics, space

A surprising star collision is making scientists rethink what they know about the universe.

Feb 20, 2020

Does our Universe have a twin?

Posted by in categories: cosmology, physics

Is our Universe really the only one? A new theory that hopes to solve one of the biggest problems in physics, may have rewritten our perception of time, and found a way through the Big Bang. Video by Howard Timberlake.

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Feb 19, 2020

Cosmology: Uncovering the Story of the Universe

Posted by in categories: cosmology, physics

Cosmology draws on many branches of physics to study the universe’s history. And what it’s found has forever changed how we understand our position in the cosmos.