Daily Archives: November 25, 2022

Physicists solve 50-year lightning mystery – why does it zigzag and what does it have to do with thunder

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[…]

For the past 50 years, scientists around the world have debated why lightning zig-zags and how it is connected to the thunder cloud above.

There hasn’t been a definitive explanation until now, with a University of South Australia plasma physicist publishing a landmark paper that solves both mysteries.

[…]

The answer? Singlet-delta metastable oxygen molecules.

Basically, lightning happens when electrons hit oxygen molecules with enough energy to create high energy singlet delta oxygen molecules. After colliding with the molecules, the “detached” electrons form a highly conducting step—initially luminous—that redistributes the , causing successive steps.

The conducting column connecting the step to the cloud remains dark when electrons attach to neutral , followed by immediate detachment of the electrons by singlet delta molecules.

[…]

he paper, “Toward a theory of stepped leaders in ” is published in the Journal of Physics D: Applied Physics. It is authored by Dr. John Lowke and Dr. Endre Szili from the Future Industries Institute at the University of South Australia.

More information: John J Lowke et al, Toward a theory of “stepped-leaders” of lightning, Journal of Physics D: Applied Physics (2022). DOI: 10.1088/1361-6463/aca103

Source: Physicists strike gold, solving 50-year lightning mystery

Bright light from black holes caused by particle shock waves

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Beams of electrons smash into slower-moving particles causing a shock wave which results in electromagnetic radiation across frequency bands from X-rays to visible light, according to a research paper published in Nature this week.

Astronomers first observed quasi-stellar radio sources or quasars in the early 1960s. This new class of astronomical objects was a puzzle. They looked like stars, but they also radiated very brightly at radio frequencies, and their optical spectra contained strange emission lines not associated with “normal” stars. In fact, these strange objects are gigantic black holes at the center of distant galaxies.

Particle acceleration in the jet emitted by a supermassive black hole. Liodakis et al/Nature

Particle acceleration in the jet emitted by a supermassive black hole. Illustration credit: Liodakis et al/Nature

Advances in radio-astronomy and X-ray-observing satellites have helped scientists understand that the anomalous radiation is caused by a stream of charged particles accelerated close to the speed of light. If it points at Earth, the generating quasar can be called a blazar. Electromagnetic radiation from them can be observed from radio waves through the visible spectrum to very high-frequency gamma rays.

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By comparing polarized X-rays data with data about optical polarized visible light, the scientists reached the conclusion that the electromagnetic radiation resulted from a shock wave in the stream of charged particles emitting from the blackhole (see figure).

In an accompanying article, Lea Marcotulli, NASA Einstein Postdoctoral Fellow at Yale University, said: “Such shock waves occur naturally when particles travelling close to the speed of light encounter slower-moving material along their path. Particles traveling through this shock wave lose radiation rapidly and efficiently – and, in doing so, they produce polarized X-rays. As the particles move away from the shock, the light they emit radiates with progressively lower frequencies, and becomes less polarized.”

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In December last year, a SpaceX Falcon 9 rocket launched NASA’s IXPE mission into orbit from Florida’s Kennedy Space Center. It is designed to observe the remnants of supernovae, supermassive black holes, and other high-energy objects.

[…]

Source: Bright light from black holes caused by particle shock waves • The Register

Omega Recreated the James Bond Opening on $7,600 Seamaster watch

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[…] The standard version of the Omega Seamaster Diver 300M 60 Years Of James Bond watch features a design that aBlogtoWatch describes as, “a blend between the original Omega Seamaster Diver 300M that appeared in GoldenEye and the latest edition from No Time To Die.” In other words, it’s a not an exact recreation of the piece that Brosnan wore in GoldenEye, but incorporates elements from several watches featured in various Bond films. On the front, the only hint that this watch is in any way Bond themed is the number 60 appearing at top of the dial, where there is normally a triangle.

A close-up of the sapphire crystal window on the Omega Seamaster Diver 300M 60 Years Of James Bond watch's caseback.
Image: Omega

It’s only when you flip the watch over that its Bond theming is far more apparent. The caseback features a sapphire glass window revealing an animation recreating the iconic opening of Bond films where the silhouetted character walks on screen as seen through the barrel of a gun. But there’s no LCD or OLED screens here. The Seamaster Diver 300M is a purely mechanical timepiece, so to create the animation, Omega leveraged the moiré effect where interference patterns from spiral patterns on spinning discs reveal the sequence of a simple four-frame animation of Bond walking in. And because the animation mechanism is tied to the watch’s moving second-hand, it perpetually plays in a loop as long as the watch has power and is keeping time.

OMEGA Seamaster Diver 300M 60 Years Of James Bond – Stainless Steel

It’s a fun design element not only because of how subtly it’s executed, but also how it leverages what makes traditional timepieces appealing to many collectors: the complicated mechanics inside that make them work. Unfortunately, with a $7,600 price tag, the Seamaster Diver 300M 60 Years Of James Bond is not really affordable for most Bond fans.

Source: Omega Recreated the James Bond Opening on This $7,600 Watch