Posts by: Hamish Johnston

How the banjo got its twang, love in the time of science, award-winning astro images and more

Five string banjo showing the position of the bridge on the head. (Courtesy: Wikipedia/CC BY-SA 3.0)

Five string banjo showing the position of the bridge on the round head. (CC BY-SA 3.0 / DMacks)

By Tushna Commissariat and Hamish Johnston

Folk and country music often blends the sharp twang of a banjo with the mellow and sustained tone of a guitar.  While the two instruments appear to be very similar – at least at first glance – they have very different sounds. This has long puzzled some physicists, including Nobel laureate David Politzer, who may have just solved this acoustical mystery.

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Proton therapy is for the masses

Drawing of the proposed proton-therapy facility

Drawing of the proposed proton-therapy facility. (Courtesy: Umar Masood)

By Hamish Johnston

In the 25th anniversary issue of Physics World, I made the bold assertion that laser acceleration will bring particle therapy to the masses by removing the need for treatment centres to have large and expensive accelerators. Instead, therapeutic beams of protons and other charged particles will be made using compact and relatively inexpensive lasers.

Now, medical physicist Umar Masood and colleagues at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Dresden have published plans for a laser-driven proton-therapy facility.

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Breaking the diffraction limit

The nanophotonics panel: Jennifer Dionne (left), Satoshi Kawata (middle) and Adarsh Sandhu

The nanophotonics panel: Jennifer Dionne (left), Satoshi Kawata (middle) and Adarsh Sandhu.

By Hamish Johnston

At first glance, visible light and nanotechnology seem incompatible because of the diffraction limit, which dictates that features smaller than about half the wavelength of light cannot be resolved optically. For visible light, the diffraction limit is about 300 nm and this means that there is no point in trying to make conventional optical components that are any smaller.

But that pessimistic outlook has changed over the past decade or so thanks to the development of nanophotonics, which makes use of near-field (or evanescent) light and plasmons to manipulate light on length scales much smaller than the diffraction limit. Today, nanophotonics is being used across a range of disciplines, including biological imaging, telecommunications, solar energy and semiconductor processing.

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Comedy at CERN, physics in a Buridanian universe and separating sugar from sand

Curtain call at CERN: last year's comedy show was a great success (Courtesy: Comedy Collider)

Curtain call at CERN: last year’s comedy show was a great success. (Courtesy: Comedy Collider)

By Hamish Johnston

Bad Boy of Science” Sam Gregson and colleagues are organizing an evening of physics-related comedy at CERN in Geneva on Friday 13 June. “LHComedy: No Cause for ConCERN” will kick off in the CERN Globe at 19:30 and is billed as “a fantastic and innovative new way of presenting the work going on at CERN and engaging with the public”. The line-up from CERN includes Canadian PhD student Nazim “License to Thrill” Hussain, quantum diarist Aidan “The Mole” Randle-Conde and Cat “Schrödinger” Demetriades. You can watch last year’s comedy extravaganza from CERN here. Others involved in the project are Clara Nellis, Alex Brown, Hugo Day, Claire Lee and Rob Knoops.

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Cosmic blunders that have held back science

Big enough already: Portrait of Edward Pickering by Sarah Gooll Putnam (Courtesy: Harvard University Portrait Collection)

Big enough already: portrait of Edward Pickering by Sarah Gooll Putnam. (Courtesy: Harvard University Portrait Collection)

By Hamish Johnston

Can you name 10 blunders that have held back the progress of modern astronomy? Avi Loeb of Harvard University can, and he lists them in an essay entitled “On the benefits of promoting diversity of ideas”, which is posted on the arXiv preprint server.

Loeb argues that a common flaw of astronomers is to believe that they know the truth even when data are scarce. This, he argues, “occasionally leads to major blunders by which the scientific community makes the wrong strategic decision in its research plans, causing unnecessary delays in finding the truth”.

The first example he gives is the 1909 pronouncement by Edward Pickering, director of the Harvard College Observatory, that telescopes had reached their optimal size and that there was no point trying to make them any bigger.

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A new Longitude Prize, global cooling in the 1970s, inspirational creatures and more

A red kite and a drone swoop down on their prey (Courtesy: Vijay Kumar)

A red kite and a drone swoop down on their prey. (Courtesy: Vijay Kumar)

By Hamish Johnston

A bird of prey swoops out of the sky, grabs its victim from the ground and flies off into the distance. It’s what a bird does instinctively, but how could we get a drone aircraft to do the same thing? That’s the subject of one of the papers in a special issue of the journal Bioinspiration & Biomimetics that focuses on “Bioinspired flight control”.

The above sequence of images is from a paper entitled “Toward autonomous avian-inspired grasping for micro aerial vehicles” by Vijay Kumar and colleagues at the University of Pennsylvania. The special issue also includes work on aircraft inspired by flying snakes, flocking birds and incredibly stable moths.

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Microwave pockets, space station strife and dreaming of Mars

Russia has the toilets on the ISS (Courtesy: NASA)

Russia has the toilets on the ISS. (Courtesy: NASA)

By Hamish Johnston

The physics of how the contents of a microwaved pastry can become “hotter than the Sun” is the subject of an entertaining and informative blog entry by Ethan Siegel. He looks at the physics of heating “microwave pockets”, those roof-of-your-mouth-scalding savoury treats that appeared on shelves in the 1980s. He explains why the outer portion of a pocket can be extremely hot, while the interior remains frozen – and why pockets often explode when heated through.

Siegel’s been a bit cheeky and republished this entry from 2009, but I suppose it’s timeless and I’m sure you can still buy microwave pockets somewhere! His blog is called Starts With a Bang and the entry is entitled “Throwback Thursday: The physics of hot pockets”.

As the crisis in the Ukraine drags on, scientists are beginning to worry about the effect it could have on scientific collaborations involving Russia and the West. Several websites are reporting that Russia is threatening to ban US astronauts from the shuttles that travel to the International Space Station (ISS). Indeed, the Independent quotes Russia’s deputy prime minister Dmitry Rogozin as saying that it would be possible for Russia to independently operate its portion of the ISS, while the US would not be able to do so. Indeed both toilets on the ISS are Russian, so it could get very messy up there!

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The biophysics of Godzilla, skipping stones, Schrödinger in the morning and more

 

By Hamish Johnston

I’m a bit of a connoisseur of the art of stone skipping. That’s because I grew up a stone’s throw from the western end of Lake Ontario, which thanks to its shale shoreline has the best skipping stones in the world. As a result, I was fascinated to read a piece on the Figure One blog about entitled “Frisbee meets fluid: Skipping stones takes spin and skill”.

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Scientists face discrimination when choosing a PhD

By Hamish Johnston

One of the most important decisions any aspiring scientist must make is what they should study for their PhD. Therefore, any advice that they receive from established academic researchers is of great value – and many academics are very generous with their time when it comes to mentoring up-and-coming researchers.

But do academics tend to reach out to some groups of people while ignoring others? That’s the subject of a study by three business-school professors – Katherine Milkman, Modupe Akinola and Dolly Chugh – who wanted to know if a person’s gender or ethnic origin affects their chances of booking an appointment with an academic to discuss their future.

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Winning rock-paper-scissors, meeting a future Nobel laureate, hot new batteries and more

By Hamish Johnston

Donald Sadoway wants us to think differently about batteries

Donald Sadoway wants us to think differently about batteries. (Courtesy: MIT/M Scott Brauer)

When I was a PhD student, there was a group of retired professors that shared a tiny office in the physics department. It was whispered that one of them was extremely wealthy thanks to a successful commercial spin-out and we marvelled at the fact that he came in to work every day rather than enjoying the fruits of his labours. However, it wasn’t the wealthy professor who was destined for international fame. In 1994 his officemate Bertram Brockhouse shared the Nobel Prize for Physics, and Brockhouse’s quiet life changed dramatically. Indeed, he got his own office!

I was reminded of this little group when I read ZapperZ’s blog entry about his encounter with Ray Davis before Davis bagged the 2002 Nobel for his work on neutrinos. Sitting next to Davis on a two-hour flight, ZapperZ had an inkling that he was beside an interesting character after their brief chat about physics. But it wasn’t until the Nobel was announced several years later that he realized the opportunity he had missed.

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