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The microscope revolution that’s sweeping through materials science

Scientists can’t study what they can’t measure — as David Muller knows only too well. An applied physicist, Muller has been grappling for years with the limitations of the best imaging tools available as he seeks to probe materials at the atomic scale.

One particularly vexing quarry has been ultra-thin layers of the material molybdenum disulfide, which show promise for building thin, flexible electronics. Muller and his colleagues at Cornell University in Ithaca, New York, have spent years peering at MoS2 samples under an electron microscope to discern their atomic structures. The problem was seeing the sulfur atoms clearly, Muller says. Raising the energy of the electron beam would sharpen the image, but knock atoms out of the MoS2 sheet in the process. Anyone hoping to say something definitive about defects in the structure would have to guess. “It would take a lot of courage, and maybe half the time, you’d be right,” he says.

This July, Muller’s team reported a breakthrough. Using an ultra-sensitive detector that the researchers had created and a special method for reconstructing the data, they resolved features in MoS2 down to 0.39 angstroms, two and a half times better than a conventional electron microscope would achieve. (1 Å is one-tenth of a nanometre, and a common measure of atomic bond lengths.) At once, formerly fuzzy sulfur atoms now showed up clearly — and so did ‘holes’ where they were absent. Ordinary electron microscopy is “like flying propeller planes”, Muller says. “Now we have a jet.”

Scientists Just Proved A Fundamental Quantum Physics Problem is Unsolvable

Scientists have proven for the very first time that one of the most fundamental problems of particle and quantum physics is mathematically unsolvable.

In short, they show that regardless of how no matter how perfectly we can mathematically describe a material on the microscopic level, we are never going to be able to predict its macroscopic behavior. Never.

The work was published in Nature.

Infinite-dimensional symmetry opens up possibility of a new physics—and new particles

The symmetries that govern the world of elementary particles at the most elementary level could be radically different from what has so far been thought. This surprising conclusion emerges from new work published by theoreticians from Warsaw and Potsdam. The scheme they posit unifies all the forces of nature in a way that is consistent with existing observations and anticipates the existence of new particles with unusual properties that may even be present in our close environs.

What is absolute zero?

The coldest place beyond Earth is artificial, too. Last summer, astronauts activated an experiment called the Cold Atom Lab aboard the International Space Station. The lab has attained temperatures 30 million times lower than empty space. “I’ve been working on this idea, off and on, for over 20 years,” says Robert Thompson of NASA’s Jet Propulsion Lab, one of the researchers who devised the experiment. “It feels incredible to witness it up and operating.”

What happens when matter gets that cold?

If Thompson sounds excited, it’s because ultra-cold atoms behave in fascinating and potentially useful ways. For one thing, they lose their individual identities, fusing to form a bizarre state of matter called a Bose-Einstein condensate.

Spacecraft Witness Explosion in Earth’s Magnetic Field

Magnetic fields around the Earth release strong bursts of energy, accelerating particles and feeding the auroras that glow in the polar skies. On July 11, 2017, four NASA spacecrafts were there to watch one of these explosions happen.

The process that produces these bursts is called magnetic reconnection, in which different plasmas and their associated magnetic fields interact, releasing energy. The Magnetospehric Multiscale Mission (MMS) satellites launched in 2015 to study the places where this reconnection process occurs. This newly released research shows for the first time that the mission encountered one of these reconnection sites in the night side of the Earth’s magnetic field, which extends behind the planet as a long “magnetotail.”