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Category: physics – Page 116

A key to the future of robots could be hiding in liquid crystals

Robots and cameras of the future could be made of liquid crystals, thanks to a new discovery that significantly expands the potential of the chemicals already common in computer displays and digital watches.

The findings, a simple and inexpensive way to manipulate the molecular properties of liquid crystals with , are now published in Advanced Materials.

“Using our method, any lab with a microscope and a set of lenses can arrange the liquid crystal alignment in any pattern they’d want,” said author Alvin Modin, a doctoral researcher studying physics at Johns Hopkins. “Industrial labs and manufacturers could probably adopt the method in a day.”

Researchers reveal anomalous heating in the sun’s upper atmosphere

In a study published in The Astrophysical Journal, researchers from the Yunnan Observatories of the Chinese Academy of Sciences depicted a complete physical image of the anomalous heating in the upper atmosphere of the sun (the solar corona and the solar chromosphere).

The enigma of the corona’s anomalous heating stands as one of the eight challenges in modern astronomy. Similarly, the anomalous heating of the chromosphere continues to baffle solar physicists.

Observations gleaned from large telescopes and satellites have revealed potential magnetic activities that could be the cause of this heating. Theoretical research has proposed various heating modes, yet none have been definitively proven to be the cause. As it stands, our understanding of how the sun’s upper atmosphere is heated remains incomplete.

New laser experiment spins light like a merry-go-round

In day-to-day life, light seems intangible. We walk through it and create and extinguish it with the flip of a switch. But, like matter, light actually carries a little punch—it has momentum. Light constantly nudges things and can even be used to push spacecraft. Light can also spin objects if it carries orbital angular momentum (OAM)—the property associated with a rotating object’s tendency to keep spinning.

Scientists have known that light can have OAM since the early 90s, and they’ve discovered that the OAM of light is associated with swirls or vortices in the light’s phase—the position of the peaks or troughs of the electromagnetic waves that make up the light. Initially, research on OAM focused on vortices that exist in the cross-section of a light beam—the phase turning like the propeller of a plane flying along the light’s path.

But in recent years, physicists at UMD, led by UMD Physics Professor Howard Milchberg, have discovered that light can carry its OAM in a vortex turned to the side—the phase spins like a wheel on a car, rolling along with the light. The researchers called these light structures spatio-temporal optical vortices (STOVs) and described the momentum they carry as transverse OAM.

Black Holes Were Such an Extreme Concept, Even Einstein Had His Doubts

Einstein’s theory of relativity paved the way for black holes’ discovery, but the concept behind their existence was so bizarre that even the scientific visionary was not convinced.

More than a century ago, Albert Einstein stunned the world when he explained the universe through his theory of general relativity. The theory not only described the relationship between space, time, gravity and matter, it opened the door to the theoretical possibility of a particularly mind-boggling phenomenon that would eventually be called black holes.

The concept that explains black holes was so radical, in fact, that Einstein, himself, had strong misgivings. He concluded in a 1939 paper in the Annals of Mathematics that the idea was “not convincing” and the phenomena did not exist “in the real world.”

The unveiling of the first-ever picture of a black hole by the Event Horizon Telescope in April 2019, however, not only confirmed Einstein’s original theory, but also provided indisputable proof that the gravitational monsters are, in fact, real.

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