Photons Explain Dark Energy

 

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When it comes to the Universe, there are some things we can be confident are out there based on what we observe. 

We know that the Universe was hotter, denser, and more uniform in the distant past. We know that the stars and galaxies in the Universe have grown up and evolved as the Universe has aged. 

We know that gravitation has formed the large-scale structure in the Universe, and that structure has grown more complex over time. 

And we also know how much normal matter, altogether, is present in the Universe, and that it isn’t sufficient to explain the full suite of the gravitational effects that we see on its own.  READ MORE...

Ending Civilization

TO A PHOTON, the sun is like a crowded nightclub. It’s 27 million degrees inside and packed with excited bodies—helium atoms fusing, nuclei colliding, positrons sneaking off with neutrinos. 

When the photon heads for the exit, the journey there will take, on average, 100,000 years. (There’s no quick way to jostle past 10 septillion dancers, even if you do move at the speed of light.) 

Once at the surface, the photon might set off solo into the night. Or, if it emerges in the wrong place at the wrong time, it might find itself stuck inside a coronal mass ejection, a mob of charged particles with the power to upend civilizations.

The cause of the ruckus is the sun’s magnetic field. Generated by the churning of particles in the core, it originates as a series of orderly north-to-south lines. But different latitudes on the molten star rotate at different rates—36 days at the poles, and only 25 days at the equator. 

Very quickly, those lines stretch and tangle, forming magnetic knots that can puncture the surface and trap matter beneath them. From afar, the resulting patches appear dark. They’re known as sunspots. Typically, the trapped matter cools, condenses into plasma clouds, and falls back to the surface in a fiery coronal rain. 

Sometimes, though, the knots untangle spontaneously, violently. The sunspot turns into the muzzle of a gun: Photons flare in every direction, and a slug of magnetized plasma fires outward like a bullet.  READ MORE...

Interior of Protons Entangled

If a photon carries too little energy, it does not fit inside a proton (left). A photon with sufficiently high energy is so small that it flies into the interior of a proton, where it 'sees' part of the proton (right). Maximum entanglement then becomes visible between the 'seen' and 'unseen' areas. Credit: IFJ PAN



Fragments of the interior of a proton have been shown by scientists from Mexico and Poland to exhibit maximum quantum entanglement. The discovery, already confronted with experimental data, allows us to suppose that in some respects the physics of the inside of a proton may have much in common not only with well-known thermodynamic phenomena, but even with the physics of... black holes.

Various fragments of the inside of a proton must be maximally entangled with each other, otherwise theoretical predictions would not agree with the data collected in experiments, it was shown in European Physical Journal C. 

The theoretical model (which extends the original proposal by physicists Dimitri Kharzeev and Eugene Levin) makes it possible to suppose that, contrary to current belief, the physics operating inside protons may be related to such concepts as entropy or temperature, which in turn may relate it to such exotic objects as black holes. 

The authors of the discovery are Dr. Martin Hentschinski from the Universidad de las Americas Puebla in Mexico and Dr. Krzysztof Kutak from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow, Poland.

The Mexican-Polish theorists analyzed the situation in which electrons are fired at protons. When an incoming electron carrying a negative electric charge approaches a positively charged proton, it interacts with it electromagnetically and deflects its path. 

Electromagnetic interaction means that a photon has been exchanged between the electron and the proton. The stronger the interaction, the greater the change in momentum of the photon and therefore the shorter the associated electromagnetic wave.  READ MORE...

Colliding Photons

Collide light with light, and poof, you get matter and antimatter. It sounds like a simple idea, but it turns out to be surprisingly hard to prove.

A team of physicists is now claiming the first direct observation of the long-sought Breit-Wheeler process, in which two particles of light, or photons, crash into one another and produce an electron and its antimatter counterpart, a positron. 

But like a discussion from an introductory philosophy course, the detection’s significance hinges on the definition of the word “real.” Some physicists argue the photons don’t qualify as real, raising questions about the observation’s implications.

Predicted more than 80 years ago, the Breit-Wheeler process had never been directly observed, although scientists have seen related processes, such as light scattering off of light (SN: 8/14/17). 

New measurements from the STAR experiment at Brookhaven National Laboratory’s Relativistic Heavy Ion Collider match predictions for the elusive transformation, Brookhaven physicist Daniel Brandenburg and colleagues report in the July 30 Physical Review Letters.

“The idea that you can create matter from light smashing together is an interesting concept,” says Brandenburg. 

It’s a striking demonstration of the physics immortalized in Einstein’s equation E=mc2, which revealed that energy and mass are two sides of the same coin.  READ MORE

Math & Black Holes

A new set of equations can precisely describe the reflections of the Universe that appear in the warped light around a black hole.

The proximity of each reflection is dependent on the angle of observation with respect to the black hole, and the rate of the black hole's spin, according to a mathematical solution worked out by physics student Albert Sneppen of the Niels Bohr Institute in Denmark.

This is really cool, absolutely, but it's not just really cool. It also potentially gives us a new tool for probing the gravitational environment around these extreme objects.

"There is something fantastically beautiful in now understanding why the images repeat themselves in such an elegant way," Sneppen said. "On top of that, it provides new opportunities to test our understanding of gravity and black holes."

If there's one thing that black holes are famous for, it's their extreme gravity. Specifically that, beyond a certain radius, the fastest achievable velocity in the Universe, that of light in a vacuum, is insufficient to achieve escape velocity.

That point of no return is the event horizon – defined by what's called the Schwarszchild radius – and it's the reason why we say that not even light can escape from a black hole's gravity.  TO READ MORE