Science

Wavy hair: a superradiant black hole A potentially explosive phenomenon called superradiance could give black holes hair – according to William East of the Perimeter Institute for Theoretical Physics in Canada and Frans Pretorius of Princeton University in the US. Their claim relies on the existence of an extremely light particle and could be confirmed by detecting gravitational waves associated with the hair. Black holes famously have “no hair”. This is the conventional idea that a black hole can only be described in terms of three quantities: mass, angular momentum and charge. All other physical properties (the hair) of the stuff that has been sucked into a black hole are lost forever. Evidence for the no-hair theorem has been seen by LIGO, which has detected the gravitational waves produced when two black holes merge. However, the idea of having no hair does not sit very well with basic principles of quantum mechanics and as a …

Saturn’s mystery: the ringed planet seems to have no tilting magnetic field Saturn’s magnetic field has no discernible tilt relative to the planet’s rotational axis, according to data from NASA’s Cassini spacecraft. This unexpected result means the exact length of a day on the planet is still unknown. Cassini is currently undergoing its Grand Finale phase – 22 weekly orbits of Saturn that take the spacecraft between the planet and its rings. This stage of the Cassini’s mission began on 26 April and it has completed 14 of the orbits. After 22, Cassini will perform its final act and plummet into the planet’s atmosphere on September 15. Aligned and challenging Among the vast swathes of data sent back by Cassini, the spacecraft’s magnetometer instrument has revealed that Saturn’s magnetic field is closely aligned to its rotational axis. The tilt is in fact much smaller than the lower limit (0.06°) the magnetometer data indicated before the …

Shovel ready: officials at the Long-Baseline Neutrino Facility break ground Construction has begun on a huge neutrino facility located at the Sanford Underground Research Facility in Lead, South Dakota. The Long-Baseline Neutrino Facility (LBNF) will study the properties of neutrinos in unprecedented detail, as well as the differences in behaviour between neutrinos and antineutrinos. Institutions in 30 countries are involved with the LBNF, which will take about a decade to build and once complete will be the world’s highest-intensity neutrino beam. The centrepiece of the LBNF is a four-storey-high neutrino detector – dubbed the Deep Underground Neutrino Experiment (DUNE) – that will be built almost 1500 m underground in South Dakota. The detector is made up of four tanks that are each filled with 17,000 tonnes of liquid argon. Underground journey DUNE will measure the neutrinos that are generated by Fermilab, which lies around 1300 km away just outside Chicago. Fermilab will accelerate protons before smashing them …

Leading the challenge: Richard Parry-Jones The UK government has launched the “Faraday Challenge”, which will invest £246m in boosting the country’s expertise in developing battery technology. Running over four years, the first phase of the programme will include a competition to develop a £45m “Battery Institute” that will provide a framework for battery research and development. The institute will be a consortium of universities that will be selected by the Engineering and Physical Sciences Research Council, which provides government funding for research in the UK. Promising research done by the Battery Institute and elsewhere in the UK will be moved towards commercialization through collaborations between academia and industry. This process will be facilitated by Innovate UK, which is a government body that provides funding to companies for the development of new products and services based on science and technology. Manufacturing development The Faraday Challenge will also fund a new National Battery Manufacturing Development Facility for …

Archimedes’ cat: dipping objects in a water tank reveals complex structures Scientists have used Archimedes’ ancient principle of water displacement to develop a new 3D scanning and reconstruction technique. The method was developed by an international team led by Kfir Aberman, Oren Katzir, Daniel Cohen-Or and colleagues at Tel-Aviv University in Israel, who have used it to successfully reconstruct complex objects including cavities. Typically, 3D scanning and reconstruction methods use optical devices that probe the visible surface of an object. While these techniques are reasonably efficient, they cannot capture features of an object that are hidden from the optics’ line of sight. Conventional methods also struggle with glossy or transparent surfaces, which can result in noisy scans. Archimedes approach To overcome these limitations, Aberman, Katzir and colleagues took a different approach. Rather than relying on optics they turned to Archimedes’ principle, which states that “the volume of fluid displaced is equal to the volume of …

Four’s company: does the tetraneutron exist? Is it possible for four neutrons to bind together to create an uncharged nucleus called a “tetraneutron”? The answer is a qualified “yes”, according to physicists in the US and France. The idea of a tetraneutron goes back several decades, but it was not until in 2002 that the first tentative experimental evidence was found – by an international team of physicists working at the GANIL nuclear physics lab in France. Near discovery Then, in 2016, physicists working at the RIKEN nuclear-physics lab in Japan found evidence for tetraneutron in a different experiment that involved firing neutron-rich helium-8 nuclei at a helium-4 target. While they did not see direct evidence for a tetraneutron, careful measurements of the two helium-four particles produced in the collision suggest that the other four neutrons involved in the collision emerge in a bound state. The statistical significance of the measurement was 4.9σ – just …

Neutron star: could superfluid helium detect gravitational waves from nearby pulsars like this one? Gravitational waves from nearby pulsars could be detected using just a few kilograms of superfluid helium-4, according to physicists in the US. Their detector, which is yet to be built, would measure sound waves in the superfluid caused by gravitational waves in the 0.1–1.5 kHz range. Gravitational waves are ripples in space–time that are created when massive objects are accelerated under certain conditions. The first gravitational-wave detection was made in 2015, when the LIGO observatory spotted a signal from a coalescing binary black hole. Two more gravitational waves have since been detected by LIGO, both associated with binary black holes. LIGO is a wideband detector that can detect signals in the 10 Hz–5 kHz range. It is particularly good at detecting transient signals (that change in frequency) associated with coalescing black holes. Low-noise measurement Swati Singh of Williams College, Laura DeLorenzo and Keith Schwab …

Attosecond science: Paul Corkum receives prestigious medal Canadian physicist Paul Corkum is among 17 scientists honoured by the Royal Society‘s annual awards. The prizes recognize researchers who have made outstanding contributions to science. Corkum has been awarded a £10,000 Royal Medal for his contributions to laser physics and the relatively new field of attosecond (10–18 s) science. Currently working at the University of Ottawa, Corkum has pioneered concepts in this branch of physics. He has demonstrated how attosecond optical and electron pulses can be created by controlling the interaction between laser light and matter. Using such short electron pulses, he has made the fastest “real-time” measurements ever recorded and combined them with sub-0.1 angstrom spatial resolution. “Truly wonderful surprise” “When I received the notification informing me that I’d won the Royal Medal I thought that it was a scam – like when you get an e-mail saying you may have won $1,000,000,” says Corkum. “This was a …

Liquid planet: Saturn-like droplets A droplet of oil can be transformed into a Saturn-like ringed structure by placing it in a strong electric field – according to Quentin Brosseau and Petia Vlahovska, who did their experiments at Brown University in the US. The fantastical effect is driven by a process called electrodynamic flow, whereby an external electric field causes the movement of electric charges at the surface of a liquid drop. In turn, this motion causes the liquid within the drop to circulate in cells – and this can distort the shape of the drop. Brosseau and Vlahovska studied droplets of silicone oil suspended in castor oil and exposed to an electric field. Exactly how the drops distort is a function of the electrical properties of the two liquids, and this was adjusted by doping the castor oil with organic electrolytes. Concentric rings In one experiment, the researchers were able to flatten a millimetre-sized drop …

Unique identifier: IOP Publishing and APS back ORCID IOP Publishing, which produces Physics World, and the American Physical Society (APS) have signed an “open letter” committing them to collecting ORCID IDs for all authors submitting papers to their journals. ORCID – Open Researcher and Contributor ID – is a not-for-profit organization that provides a unique identifier (iD) for every researcher, which means they can clearly distinguish researchers with the same name. Avoiding confusion “It is extremely important that researchers are correctly recognized for their work, whether as an author, reviewer or editor, and that the community is able to cite work without confusion,” says Jamie Hutchins, publishing director at IOP Publishing. “ORCID identifiers make this easier, by removing the confusion that can be caused by similarities between researchers’ names, name changes, inconsistencies in abbreviations and cultural differences in how names are presented.” Matthew Salter, publisher at APS, adds: “With several major funders now requiring ORCID …

1 2 3 38