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Archive for the ‘particle physics’ category: Page 325

Aug 23, 2019

What’s the Total Energy In the Universe?

Posted by in category: particle physics

Circa 2011


Considering the amount of energy packed in the nucleus of a single uranium atom, or the energy that has been continuously radiating from the sun for billions of years, or the fact that there are 1080 particles in the observable universe, it seems that the total energy in the universe must be an inconceivably vast quantity. But it’s not; it’s probably zero.

Light, matter and antimatter are what physicists call “positive energy.” And yes, there’s a lot of it (though no one is sure quite how much). Most physicists think, however, that there is an equal amount of “negative energy” stored in the gravitational attraction that exists between all the positive-energy particles. The positive exactly balances the negative, so, ultimately, there is no energy in the universe at all.

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Aug 23, 2019

DARPA’s Handheld Nuclear Fusion Reactor

Posted by in categories: computing, military, nuclear energy, particle physics

fusionsunLast year, Pentagon mad science arm DARPA was working on one of its wildest projects yet: a microchip-sized nuclear reactor. The program is now officially done, the agency says. But these sorts of far-out projects have a habit of being reemerging under new managers and new names.

The project, known as the “Chip-Scale High Energy Atomic Beams” program, is an effort aimed at working on the core technologies behind a tiny particle accelerator, capable of firing subatomic particles at incredible speeds. It’s part of a larger DARPA plan to reduce all sorts of devices to microchip-scale – including cryogenic coolers, video cameras and multi-purpose sensors. All of the projects are ambitious (this is DARPA, after all). But this had to be the most ambitious of the lot. Here’s how DARPA’s plans for fiscal year 2009 described it:

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Aug 22, 2019

Scientists Just Used The Cosmos to Measure The Mass of a Ghost Particle

Posted by in categories: particle physics, space

How do you weigh a ghost? If you’re a cosmologist, you could use… the Universe. Combine vast cosmological data with info from particle accelerators, and, it turns out, you have a pretty good scale for measuring the mass of a neutrino — also known as the ‘ghost particle’.

This is how a team of scientists, for the first time, have set an upper limit on the mass of the lightest of the three different types of neutrino.

Neutrinos are peculiar little things. They are among the most abundant subatomic particles in the Universe, similar to electrons, but without a charge and almost massless. This means they interact very rarely with normal matter; in fact, billions are passing through your body right now.

Aug 22, 2019

Forget About Electrons And Protons; The Unstable Muon Could Be The Future Of Particle Physics

Posted by in categories: futurism, particle physics

The particle tracks emanating from a high energy collision at the LHC in 2014 show the creation of many new particles. It’s only because of the high-energy nature of this collision that new masses can be created.

Aug 22, 2019

‘Electron pairing’ found well above superconductor’s critical temperature

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

Physicists have found “electron pairing,” a hallmark feature of superconductivity, at temperatures and energies well above the critical threshold where superconductivity happens.

Rice University’s Doug Natelson, co-corresponding author of a paper about the work in this week’s Nature, said the discovery of Cooper pairs of electrons “a bit above the critical temperature won’t be ‘crazy surprising’ to some people. The thing that’s more weird is that it looks like there are two different energy scales. There’s a higher energy scale where the pairs form, and there’s a lower energy scale where they all decide to join hands and act collectively and coherently, the behavior that actually brings about superconductivity.”

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Aug 21, 2019

Astrophysical shock phenomena reproduced in the laboratory

Posted by in categories: cosmology, particle physics, space travel

Vast interstellar events where clouds of charged matter hurtle into each other and spew out high-energy particles have now been reproduced in the lab with high fidelity. The work, by MIT researchers and an international team of colleagues, should help resolve longstanding disputes over exactly what takes place in these gigantic shocks.

Many of the largest-scale events, such as the expanding bubble of matter hurtling outward from a supernova, involve a phenomenon called collisionless . In these interactions, the clouds of gas or plasma are so rarefied that most of the particles involved actually miss each other, but they nevertheless interact electromagnetically or in other ways to produces visible shock waves and filaments. These high-energy events have so far been difficult to reproduce under laboratory conditions that mirror those in an astrophysical setting, leading to disagreements among physicists as to the mechanisms at work in these astrophysical phenomena.

Now, the researchers have succeeded in reproducing critical conditions of these collisionless shocks in the laboratory, allowing for detailed study of the processes taking place within these giant cosmic smashups. The new findings are described in the journal Physical Review Letters, in a paper by MIT Plasma Science and Fusion Center Senior Research Scientist Chikang Li, five others at MIT, and 14 others around the world.

Aug 21, 2019

Colour-changing artificial ‘chameleon skin’ powered by nanomachines

Posted by in categories: nanotechnology, particle physics

Researchers have developed artificial ‘chameleon skin’ that changes color when exposed to light and could be used in applications such as active camouflage and large-scale dynamic displays.

The material, developed by researchers from the University of Cambridge, is made of tiny particles of gold coated in a polymer shell, and then squeezed into microdroplets of water in oil. When exposed to heat or , the particles stick together, changing the color of the material. The results are reported in the journal Advanced Optical Materials.

In nature, animals such as chameleons and cuttlefish are able to change color thanks to chromatophores: skin cells with contractile fibers that move pigments around. The pigments are spread out to show their color, or squeezed together to make the cell clear.

Aug 21, 2019

For The First Time Ever, Scientists Have Made a Stable Ring of Pure Carbon

Posted by in category: particle physics

Carbon can be arranged in a number of configurations. When each of its atoms is bonded to three other carbon atoms, it’s relatively soft graphite. Add just one more bond and it becomes one of the hardest minerals known, diamond. Chuck 60 carbon atoms together in a soccerball shape and boom, buckyballs.

But a ring of carbon atoms, where each atom is bonded to just two others, and nothing else? That’s eluded scientists for 50 years. Their best attempts have resulted in a gaseous carbon ring that quickly dissipated.

So it’s a pretty big deal that a team of researchers, from Oxford University and IBM Research, has now created a stable carbon ring.

Aug 20, 2019

A New Experiment Narrows Potential Properties of Dark Energy Particle

Posted by in categories: cosmology, particle physics

An experiment in the United Kingdom has failed to find evidence of a particle meant to explain most of the universe’s mass. But the search isn’t over.

When cosmologists observe the way the universe expands, they find that present-day theories of matter can’t explain most of the universe’s energy. They call the unknown energy “dark energy,” and theorists have tried to explain it by proposing undiscovered particles and corresponding fields. Experiments have failed to find evidence of such particles, but in physics, that’s not necessarily a bad thing.

Aug 20, 2019

Team develops robust molecular propeller for unidirectional rotations

Posted by in categories: biological, particle physics

A team of scientists from Ohio University, Argonne National Laboratory, Universitié de Toulouse in France and Nara Institute of Science and Technology in Japan led by Ohio Professor of Physics Saw-Wai Hla and Prof. Gwenael Rapenne from Toulouse developed a molecular propeller that enables unidirectional rotations on a material surface when energized.

In nature, molecule propellers are vital in many biological applications ranging from the swimming bacteria to intracellular transport, but synthetic molecular propellers, like what has been developed, are able to operate in harsher environments and under a precise control. This new development is a multiple component molecular specially designed to operate on solid surfaces. This tiny propeller is composed of three components; a ratchet shape molecular gear as a base, a tri-blade propeller, and a ruthenium atom acting as an atomic ball bearing that connects the two. The size of the propeller is only about 2 nanometers (nm) wide and 1 nm tall.

“What is special about our propeller is its multi-component design that becomes chiral on the gold crystal surface, i.e. it forms right- or left-tilted gears,” said Hla. “This chirality dictates the rotational direction when energized.”