Category Archives: General
By Tushna Commissariat
Drops of water normally tend to splash when they strike a surface. But what happens if they hit something very cold? It turns out they first freeze and then crack, forming intricate fracture patterns, one of which you can see in the image above.
It was taken using a high-speed camera by Christophe Josserand, Thomas Séon and colleagues at the Jean Le Rond d’Alembert Institute in France. They watched water solidifying as it dripped onto a stainless-steel surface cooled to various temperatures between 0 and −60 °C (Phys. Rev. Lett. 117 074501). Due to the contact between the drop and the surface, the water’s ability to freeze is limited and mechanical stress makes it fracture in a few milliseconds.
By Margaret Harris
A couple of years ago, I came across what I thought was a funny (and physics-related) video about a water slide. The slide is called “Verrückt”, which my German-speaking colleagues translate as “mad” or “crazy”, and it caught my attention because it was being built at an amusement park in my home town of Kansas City. As the video shows, the slide experienced a few problems during its testing phase.
“When the rafts are loaded with more than 1000 pounds, the slide becomes unsafe,” says the video’s announcer as the test raft goes airborne. “We’re going to have to redesign the entire slide,” an unnamed official adds.
By Tushna Commissariat
After months of rumours, speculation and some 500 papers posted to the arXiv in an attempt to explain it, the ATLAS and CMS collaborations have confirmed that the small excess of diphoton events, or “bump”, at 750 GeV detected in their preliminary data is a mere statistical fluctuation that has disappeared in the light of more data. Most folks in the particle-physics community will have been unsurprised if a bit disappointed by today’s announcement at the International Conference on High Energy Physics (ICHEP) 2016, currently taking place in Chicago.
The story began around this time last year, soon after the LHC was rebooted and began its impressive 13 TeV run, when the ATLAS collaboration saw more events than expected around the 750 GeV mass window. This bump immediately caught the interest of physicists the world over, simply because there was a sniff of “new physics” around it, meaning that the Standard Model of particle physics did not predict the existence of a particle at that energy. But also, it was the first interesting data to emerge from the LHC after its momentous discovery of the Higgs boson in 2012 and if it had held, would have been one of the most exciting discoveries in modern particle physics.
By Matin Durrani
Over the past year the world’s computers, mobile phones and other devices generated some 12 zettabytes of data. And by 2020 that number is predicted to rise to 44 zettabytes – nearly as many bits as there are stars in the universe.
In the August 2016 issue of Physics World magazine – now live in the Physics World app for mobile and desktop – Harald Haas from the University of Edinburgh in the UK explains how the humble household light bulb could soon be transformed into the backbone of a revolutionary new wireless communications network based on visitible light.
Known as “LiFi”, the system could not only contribute to next-generation 5G mobile-phone systems, but also unlock the potential of the “Internet of things”, create”smart” cities, help with the introduction of driverless cars and offer new ways to monitor the health of old people. You can also read the article here.
The August issue also shows how neutrons could help in the search for new drugs, why we need to solve the ethical dilemmas surrounding space mining, and how physicists are helping to save daguerreotype photographs from decay. Don’t miss either our look at the impact of Brexit on European physics.
By Margaret Harris
As I prepared to travel to Manchester earlier this week for the 2016 European Science Open Forum (ESOF), I had an unwanted extra item on my to-do list: working out, in detail, whether it was physically possible for me to attend.
My problem was my foot: a few weeks ago, I broke it, and as ESOF approached, it became clear that my injury wouldn’t heal in time. I was wary of trying to do a conference on crutches, but the reassuring responses to my queries (yes, my hotel had accessible rooms; yes, the venue for the conference, Manchester Central, was “very accessible”) convinced me that it would be okay. So I headed off to Manchester last Sunday for two days of science talks – and got an eye-opening lesson on what it’s like to attend a scientific conference with a physical disability.
By Margaret Harris
As the editor in charge of Lateral Thoughts – Physics World’s long-running column of humorous or otherwise offbeat essays on physics – I am sometimes* asked whether I have a favourite. It’s an interesting question, and back in 2014, when I was writing a series of posts for this blog about how Lateral Thoughts had changed over the (then) 25-year history of Physics World, I promised to answer it.
This, however, proved easier said than done. In the weeks that followed my foolish pledge, the Physics World inbox (firstname.lastname@example.org) received a whole series of Lateral Thoughts essays that could have been my “favourite”. One of them, published in May 2014, was John Swanson’s discourse on the quantum nature of the 20:08 train from Bristol Parkway. Another, which appeared in June 2014, contained Chris Atkins’ gloriously straight-faced analysis of the physics of Poohsticks. A third, in July 2014, saw kung-fu expert Felix Flicker explore an unexpected connection between the mathematics of spinors and the art of escaping from an armlock. Then, in August 2014, John Evans pondered various physics-based ways of improving his running – such as refining his aerodynamic profile by developing a beer belly. (Evans, incidentally, went on to write a Lateral Thought on cycling in October 2015, and this month we published his essay on swimming. This means he’s now completed a lateral-thinking triathlon. Congratulations!)
By Matin Durrani
Members of NASA’s Juno mission are bracing themselves for the final moments of the craft’s five-year-long journey to Jupiter, which will finally reach its quarry just a few days from now (late on 4 July in North America, early morning on 5 July in Europe). There’ll be an anxious, 40-minute period of radio silence as the spinning craft fires its thrusters and slows down enough to be captured by the gas giant’s gravity.
During that time, staff at NASA’s Jet Propulsion Laboratory will be waiting, nervously, for Juno’s instruments to flicker back on and allow data-taking to begin as the craft starts a year-long orbit of the planet.
For the inside story of Juno and what it hopes to achieve, don’t miss the July 2016 special issue of Physics World magazine – now live in the Physics World app for mobile and desktop. You can also read the article here.
Devoted to planetary science, the special issue includes amazing images from NASA’s New Horizons mission to Pluto, an investigation into auroras on planets other than Earth, and an analysis of what we know about Vesta and Ceres – the two largest bodies in the main asteroid belt.
By Matin Durrani, Editor, Physics World
Amid all the noise and recrimination following the UK’s vote to leave the European Union (EU) in last week’s national referendum by a majority of 52% to 48%, I was reminded of a comment that Nicola Clase – Sweden’s ambassador to Britain – made to Times columnist David Aaronovitch before the referendum. When he sought her views on a potential British exit from the EU (Brexit), Clase replied: “It’s like when a child desperately wants to pee in his pants and does it. At first there’s a feeling of relief and for a few moments it’s nice and warm. Then he’s just cold and wet.”
It was a flippant comment for sure, but not far wide off the mark. As a new week dawns, physicists in the UK – and beyond – are coming to terms with the enormity and liable consequences of the vote. A poll by Nature in March showed that the vast majority of UK scientists were overwhelmingly in support of the EU, with 83% saying “no” to an exit. Although, legally, the outcome of the referendum does not have to be acted upon, we can expect huge and completely unnecessary uncertainty over the next few months, if not longer.
Learned societies in the UK, such as the Institute of Physics, which publishes Physics World, as well as the Royal Society and the Royal Astronomical Society, have been putting a brave face on the prospect of Britain quitting the EU. They underlined the importance of maintaining free movement of scientists to and from the UK, and ensuring British scientists continue to have access to EU research funds and EU-supported facilities. It will be great if those principles and policies remain in place – but there is no guarantee they will. In any case, why should the rest of the EU now want to bother making life easy for the UK as it negotiates a Brexit?
By James Dacey
This summer many of you will watch smoke billowing out of buildings as yet another villain wreaks havoc on the New York skyline in the latest Hollywood blockbuster. I’m willing to bet that as you eat your popcorn you won’t be thinking about the Navier–Stokes equations of fluid dynamics. (Well, perhaps you will now that I’ve mentioned it!)
In fact, part of the reason that virtual smoke in films looks so realistic is because visual effects (VFX) specialists have applied the Navier–Stokes equations to their graphics. This was one of the interesting tidbits I learned from a talk yesterday in London by Rob Pieké, head of software at Moving Picture Company (MPC).
Pieké was speaking as part of a half-day event on “physics and film” organized by the Institute of Physics, which publishes Physics World. The gist of his presentation was that basic physics principles are used in a variety of ways to create special effects that capture viewers’ attention. “The audience wants to see something fantastical but grounded in reality,” said Pieké. Another example he gave was how naturally bouncing hair in computer-generated characters is modelled on mass—spring systems. Each individual hair could be modelled on as many as 30 masses connecting by springs.
By Hamish Johnston
Things are heating up in the blogosphere after two A-list physics bloggers have speculated that a tantalizing hint of new physics seen by the CMS and ATLAS experiments at CERN is vanishing now that the latest collision data are being analysed.
The hint is a bump at 750 GeV in the spectrum of photon pairs created when protons collide in the LHC. It is not predicted by the Standard Model of particle physics and has not yet reached a statistical significance of 5σ – the threshold for a discovery. If it turns out to be real, the bump could become one of the most important discoveries in particle physics made so far this century.